X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/3c8030a4977536e9d3a1954adc68082ae1c6d5a2..15fe8e62d37bc87114c59d385bed7ceefb72886b:/apt-pkg/acquire-item.h

diff --git a/apt-pkg/acquire-item.h b/apt-pkg/acquire-item.h
index 6b4f73708..e6e5ea12b 100644
--- a/apt-pkg/acquire-item.h
+++ b/apt-pkg/acquire-item.h
@@ -1,36 +1,38 @@
 // -*- mode: cpp; mode: fold -*-
 // Description								/*{{{*/
-// $Id: acquire-item.h,v 1.26.2.3 2004/01/02 18:51:00 mdz Exp $
 /* ######################################################################
 
    Acquire Item - Item to acquire
 
    When an item is instantiated it will add it self to the local list in
-   the Owner Acquire class. Derived classes will then call QueueURI to 
-   register all the URI's they wish to fetch at the initial moment.   
-   
+   the Owner Acquire class. Derived classes will then call QueueURI to
+   register all the URI's they wish to fetch at the initial moment.
+
    Three item classes are provided to provide functionality for
    downloading of Index, Translation and Packages files.
-   
+
    A Archive class is provided for downloading .deb files. It does Hash
    checking and source location as well as a retry algorithm.
-   
+
    ##################################################################### */
 									/*}}}*/
 #ifndef PKGLIB_ACQUIRE_ITEM_H
 #define PKGLIB_ACQUIRE_ITEM_H
 
 #include <apt-pkg/acquire.h>
+#include <apt-pkg/indexfile.h>
 #include <apt-pkg/hashes.h>
 #include <apt-pkg/weakptr.h>
 #include <apt-pkg/pkgcache.h>
+#include <apt-pkg/cacheiterators.h>
+
+#include <string>
+#include <vector>
+#include <map>
 
 #ifndef APT_8_CLEANER_HEADERS
-#include <apt-pkg/indexfile.h>
-#include <apt-pkg/vendor.h>
 #include <apt-pkg/sourcelist.h>
 #include <apt-pkg/pkgrecords.h>
-#include <apt-pkg/indexrecords.h>
 #endif
 
 /** \addtogroup acquire
@@ -39,11 +41,14 @@
  *  \file acquire-item.h
  */
 
-class indexRecords;
 class pkgRecords;
 class pkgSourceList;
+class pkgAcqMetaClearSig;
+class pkgAcqIndexMergeDiffs;
+class metaIndex;
 
-/** \brief Represents the process by which a pkgAcquire object should	{{{
+class pkgAcquire::Item : public WeakPointable				/*{{{*/
+/** \brief Represents the process by which a pkgAcquire object should
  *  retrieve a file or a collection of files.
  *
  *  By convention, Item subclasses should insert themselves into the
@@ -55,35 +60,7 @@ class pkgSourceList;
  *
  *  \see pkgAcquire
  */
-class pkgAcquire::Item : public WeakPointable
-{  
-   protected:
-   
-   /** \brief The acquire object with which this item is associated. */
-   pkgAcquire *Owner;
-
-   /** \brief Insert this item into its owner's queue.
-    *
-    *  \param ItemDesc Metadata about this item (its URI and
-    *  description).
-    */
-   inline void QueueURI(ItemDesc &Item)
-                 {Owner->Enqueue(Item);};
-
-   /** \brief Remove this item from its owner's queue. */
-   inline void Dequeue() {Owner->Dequeue(this);};
-   
-   /** \brief Rename a file without modifying its timestamp.
-    *
-    *  Many item methods call this as their final action.
-    *
-    *  \param From The file to be renamed.
-    *
-    *  \param To The new name of #From.  If #To exists it will be
-    *  overwritten.
-    */
-   void Rename(std::string From,std::string To);
-
+{
    public:
 
    /** \brief The current status of this item. */
@@ -108,14 +85,14 @@ class pkgAcquire::Item : public WeakPointable
 	*/
        StatAuthError,
 
-       /** \brief The item was could not be downloaded because of 
+       /** \brief The item was could not be downloaded because of
 	*  a transient network error (e.g. network down)
 	*/
-       StatTransientNetworkError
+       StatTransientNetworkError,
      } Status;
 
    /** \brief Contains a textual description of the error encountered
-    *  if #Status is #StatError or #StatAuthError.
+    *  if #ItemState is #StatError or #StatAuthError.
     */
    std::string ErrorText;
 
@@ -128,14 +105,19 @@ class pkgAcquire::Item : public WeakPointable
    /** \brief If not \b NULL, contains the name of a subprocess that
     *  is operating on this object (for instance, "gzip" or "gpgv").
     */
-   const char *Mode;
+   APT_DEPRECATED_MSG("Use the std::string member ActiveSubprocess instead") const char *Mode;
+
+   /** \brief contains the name of the subprocess that is operating on this object
+    * (for instance, "gzip", "rred" or "gpgv"). This is obsoleting #Mode from above
+    * as it can manage the lifetime of included string properly. */
+   std::string ActiveSubprocess;
 
    /** \brief A client-supplied unique identifier.
-    * 
+    *
     *  This field is initalized to 0; it is meant to be filled in by
     *  clients that wish to use it to uniquely identify items.
     *
-    *  \todo it's unused in apt itself
+    *  APT progress reporting will store an ID there as shown in "Get:42 …"
     */
    unsigned long ID;
 
@@ -151,6 +133,7 @@ class pkgAcquire::Item : public WeakPointable
     *  download progress indicator's overall statistics.
     */
    bool Local;
+
    std::string UsedMirror;
 
    /** \brief The number of fetch queues into which this item has been
@@ -162,7 +145,17 @@ class pkgAcquire::Item : public WeakPointable
     *  \sa pkgAcquire
     */
    unsigned int QueueCounter;
-   
+
+   /** \brief The number of additional fetch items that are expected
+    *  once this item is done.
+    *
+    *  Some items like pkgAcqMeta{Index,Sig} will queue additional
+    *  items. This variable can be set by the methods if it knows
+    *  in advance how many items to expect to get a more accurate
+    *  progress.
+    */
+   unsigned int ExpectedAdditionalItems;
+
    /** \brief The name of the file into which the retrieved object
     *  will be written.
     */
@@ -181,7 +174,29 @@ class pkgAcquire::Item : public WeakPointable
     *
     *  \sa pkgAcqMethod
     */
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf);
+
+   /** \brief Invoked by the acquire worker to check if the successfully
+    * fetched object is also the objected we wanted to have.
+    *
+    *  Note that the object might \e not have been written to
+    *  DestFile; check for the presence of an Alt-Filename entry in
+    *  Message to find the file to which it was really written.
+    *
+    *  This is called before Done is called and can prevent it by returning
+    *  \b false which will result in Failed being called instead.
+    *
+    *  You should prefer to use this method over calling Failed() from Done()
+    *  as this has e.g. the wrong progress reporting.
+    *
+    *  \param Message Data from the acquire method.  Use LookupTag()
+    *  to parse it.
+    *  \param Cnf The method via which the object was fetched.
+    *
+    *  \sa pkgAcqMethod
+    */
+   virtual bool VerifyDone(std::string const &Message,
+	 pkgAcquire::MethodConfig const * const Cnf);
 
    /** \brief Invoked by the acquire worker when the object was
     *  fetched successfully.
@@ -196,25 +211,24 @@ class pkgAcquire::Item : public WeakPointable
     *
     *  \param Message Data from the acquire method.  Use LookupTag()
     *  to parse it.
-    *  \param Size The size of the object that was fetched.
-    *  \param Hash The HashSum of the object that was fetched.
+    *  \param Hashes The HashSums of the object that was fetched.
     *  \param Cnf The method via which the object was fetched.
     *
     *  \sa pkgAcqMethod
     */
-   virtual void Done(std::string Message,unsigned long long Size,std::string Hash,
-		     pkgAcquire::MethodConfig *Cnf);
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf);
 
    /** \brief Invoked when the worker starts to fetch this object.
     *
     *  \param Message RFC822-formatted data from the worker process.
     *  Use LookupTag() to parse it.
     *
-    *  \param Size The size of the object being fetched.
+    *  \param Hashes The expected hashes of the object being fetched.
     *
     *  \sa pkgAcqMethod
     */
-   virtual void Start(std::string Message,unsigned long long Size);
+   virtual void Start(std::string const &Message, unsigned long long const Size);
 
    /** \brief Custom headers to be sent to the fetch process.
     *
@@ -224,45 +238,56 @@ class pkgAcquire::Item : public WeakPointable
     *  line, so they should (if nonempty) have a leading newline and
     *  no trailing newline.
     */
-   virtual std::string Custom600Headers() {return std::string();};
+   virtual std::string Custom600Headers() const;
 
    /** \brief A "descriptive" URI-like string.
     *
     *  \return a URI that should be used to describe what is being fetched.
     */
-   virtual std::string DescURI() = 0;
+   virtual std::string DescURI() const = 0;
    /** \brief Short item description.
     *
     *  \return a brief description of the object being fetched.
     */
-   virtual std::string ShortDesc() {return DescURI();}
+   virtual std::string ShortDesc() const;
 
    /** \brief Invoked by the worker when the download is completely done. */
-   virtual void Finished() {};
-   
-   /** \brief HashSum 
+   virtual void Finished();
+
+   /** \return HashSums the DestFile is supposed to have in this stage */
+   virtual HashStringList GetExpectedHashes() const = 0;
+   /** \return the 'best' hash for display proposes like --print-uris */
+   std::string HashSum() const;
+
+   /** \return if having no hashes is a hard failure or not
     *
-    *  \return the HashSum of this object, if applicable; otherwise, an
-    *  empty string.
+    * Idealy this is always \b true for every subclass, but thanks to
+    * historical grow we don't have hashes for all files in all cases
+    * in all steps, so it is slightly more complicated than it should be.
     */
-   virtual std::string HashSum() {return std::string();};
+   virtual bool HashesRequired() const { return true; }
 
    /** \return the acquire process with which this item is associated. */
-   pkgAcquire *GetOwner() {return Owner;};
+   pkgAcquire *GetOwner() const;
+   pkgAcquire::ItemDesc &GetItemDesc();
 
    /** \return \b true if this object is being fetched from a trusted source. */
-   virtual bool IsTrusted() {return false;};
-   
-   // report mirror problems
+   virtual bool IsTrusted() const;
+
    /** \brief Report mirror problem
-    * 
+    *
     *  This allows reporting mirror failures back to a centralized
     *  server. The apt-report-mirror-failure script is called for this
-    * 
+    *
     *  \param FailCode A short failure string that is send
     */
-   void ReportMirrorFailure(std::string FailCode);
+   APT_DEPRECATED_MSG("Item::Failed does this for you") void ReportMirrorFailure(std::string const &FailCode);
 
+   /** \brief Set the name of the current active subprocess
+    *
+    *  See also #ActiveSubprocess
+    */
+   void SetActiveSubprocess(std::string const &subprocess);
 
    /** \brief Initialize an item.
     *
@@ -270,88 +295,320 @@ class pkgAcquire::Item : public WeakPointable
     *  process, but does not place it into any fetch queues (you must
     *  manually invoke QueueURI() to do so).
     *
-    *  Initializes all fields of the item other than Owner to 0,
-    *  false, or the empty string.
-    *
     *  \param Owner The new owner of this item.
     */
-   Item(pkgAcquire *Owner);
+   explicit Item(pkgAcquire * const Owner);
 
    /** \brief Remove this item from its owner's queue by invoking
     *  pkgAcquire::Remove.
     */
    virtual ~Item();
 
+   bool APT_HIDDEN IsRedirectionLoop(std::string const &NewURI);
+
    protected:
+   /** \brief The acquire object with which this item is associated. */
+   pkgAcquire * const Owner;
+
+   /** \brief The item that is currently being downloaded. */
+   pkgAcquire::ItemDesc Desc;
 
    enum RenameOnErrorState {
       HashSumMismatch,
       SizeMismatch,
-      InvalidFormat
+      InvalidFormat,
+      SignatureError,
+      NotClearsigned,
+      MaximumSizeExceeded,
+      PDiffError,
    };
 
    /** \brief Rename failed file and set error
     *
     * \param state respresenting the error we encountered
-    * \param errorMsg a message describing the error
     */
    bool RenameOnError(RenameOnErrorState const state);
+
+   /** \brief Insert this item into its owner's queue.
+    *
+    *  The method is designed to check if the request would end
+    *  in an IMSHit and if it determines that it would, it isn't
+    *  queueing the Item and instead sets it to completion instantly.
+    *
+    *  \param Item Metadata about this item (its URI and
+    *  description).
+    *  \return true if the item was inserted, false if IMSHit was detected
+    */
+   virtual bool QueueURI(ItemDesc &Item);
+
+   /** \brief Remove this item from its owner's queue. */
+   void Dequeue();
+
+   /** \brief Rename a file without modifying its timestamp.
+    *
+    *  Many item methods call this as their final action.
+    *
+    *  \param From The file to be renamed.
+    *
+    *  \param To The new name of \a From.  If \a To exists it will be
+    *  overwritten. If \a From and \a To are equal nothing happens.
+    */
+   bool Rename(std::string const &From, std::string const &To);
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const;
+
+   private:
+   class Private;
+   Private * const d;
+
+   friend class pkgAcqMetaBase;
+   friend class pkgAcqMetaClearSig;
 };
 									/*}}}*/
-/** \brief Information about an index patch (aka diff). */		/*{{{*/
-struct DiffInfo {
-   /** The filename of the diff. */
-   std::string file;
+class APT_HIDDEN pkgAcqTransactionItem: public pkgAcquire::Item		/*{{{*/
+/** \brief baseclass for the indexes files to manage them all together */
+{
+   void * const d;
+   protected:
+   HashStringList GetExpectedHashesFor(std::string const &MetaKey) const;
+
+   bool QueueURI(pkgAcquire::ItemDesc &Item) APT_OVERRIDE;
+
+   public:
+   IndexTarget const Target;
+
+   /** \brief storge name until a transaction is finished */
+   std::string PartialFile;
 
-   /** The sha1 hash of the diff. */
-   std::string sha1;
+   /** \brief TransactionManager */
+   pkgAcqMetaClearSig * const TransactionManager;
 
-   /** The size of the diff. */
-   unsigned long size;
+   enum TransactionStates {
+      TransactionStarted,
+      TransactionCommit,
+      TransactionAbort,
+   };
+   virtual bool TransactionState(TransactionStates const state);
+
+   virtual std::string DescURI() const APT_OVERRIDE { return Target.URI; }
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual std::string GetMetaKey() const;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
+
+   pkgAcqTransactionItem(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager, IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqTransactionItem();
+
+   friend class pkgAcqMetaBase;
+   friend class pkgAcqMetaClearSig;
 };
 									/*}}}*/
-/** \brief An item that is responsible for fetching a SubIndex		{{{
- *
- *  The MetaIndex file includes only records for important indexes
- *  and records for these SubIndex files so these can carry records
- *  for addition files like PDiffs and Translations
- */
-class pkgAcqSubIndex : public pkgAcquire::Item
+class APT_HIDDEN pkgAcqMetaBase : public pkgAcqTransactionItem		/*{{{*/
+/** \brief the manager of a transaction */
 {
+   void * const d;
  protected:
-   /** \brief If \b true, debugging information will be written to std::clog. */
-   bool Debug;
+   std::vector<pkgAcqTransactionItem*> Transaction;
 
-   /** \brief The item that is currently being downloaded. */
-   pkgAcquire::ItemDesc Desc;
+   /** \brief If \b true, the index's signature is currently being verified.
+    */
+   bool AuthPass;
 
-   /** \brief The Hash that this file should have after download
+   /** \brief Called when a file is finished being retrieved.
+    *
+    *  If the file was not downloaded to DestFile, a copy process is
+    *  set up to copy it to DestFile; otherwise, Complete is set to \b
+    *  true and the file is moved to its final location.
+    *
+    *  \param Message The message block received from the fetch
+    *  subprocess.
     */
-   HashString ExpectedHash;
+   bool CheckDownloadDone(pkgAcqTransactionItem * const I, const std::string &Message, HashStringList const &Hashes) const;
 
- public:
-   // Specialized action members
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size,std::string Md5Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string DescURI() {return Desc.URI;};
-   virtual std::string Custom600Headers();
-   virtual bool ParseIndex(std::string const &IndexFile);
+   /** \brief Queue the downloaded Signature for verification */
+   void QueueForSignatureVerify(pkgAcqTransactionItem * const I, std::string const &File, std::string const &Signature);
 
-   /** \brief Create a new pkgAcqSubIndex.
-    *
-    *  \param Owner The Acquire object that owns this item.
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+
+   /** \brief Called when authentication succeeded.
     *
-    *  \param URI The URI of the list file to download.
+    *  Sanity-checks the authenticated file, queues up the individual
+    *  index files for download, and saves the signature in the lists
+    *  directory next to the authenticated list file.
     *
-    *  \param URIDesc A long description of the list file to download.
+    *  \param Message The message block received from the fetch
+    *  subprocess.
+    */
+   bool CheckAuthDone(std::string const &Message);
+
+   /** Check if the current item should fail at this point */
+   bool CheckStopAuthentication(pkgAcquire::Item * const I, const std::string &Message);
+
+   /** \brief Check that the release file is a release file for the
+    *  correct distribution.
     *
-    *  \param ShortDesc A short description of the list file to download.
+    *  \return \b true if no fatal errors were encountered.
+    */
+   bool VerifyVendor(std::string const &Message);
+
+   virtual bool TransactionState(TransactionStates const state) APT_OVERRIDE;
+
+ public:
+   // This refers more to the Transaction-Manager than the actual file
+   bool IMSHit;
+   TransactionStates State;
+   std::string BaseURI;
+
+   virtual bool QueueURI(pkgAcquire::ItemDesc &Item) APT_OVERRIDE;
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
+   // transaction code
+   void Add(pkgAcqTransactionItem * const I);
+   void AbortTransaction();
+   bool TransactionHasError() const;
+   void CommitTransaction();
+
+   /** \brief Stage (queue) a copy action when the transaction is committed
+    */
+   void TransactionStageCopy(pkgAcqTransactionItem * const I,
+                             const std::string &From,
+                             const std::string &To);
+   /** \brief Stage (queue) a removal action when the transaction is committed
+    */
+   void TransactionStageRemoval(pkgAcqTransactionItem * const I, const std::string &FinalFile);
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   pkgAcqMetaBase(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+		  IndexTarget const &DataTarget) APT_NONNULL(2, 3);
+   virtual ~pkgAcqMetaBase();
+};
+									/*}}}*/
+/** \brief An item that is responsible for downloading the meta-index	{{{
+ *  file (i.e., Release) itself and verifying its signature.
+ *
+ *  Once the download and verification are complete, the downloads of
+ *  the individual index files are queued up using pkgAcqDiffIndex.
+ *  If the meta-index file had a valid signature, the expected hashsums
+ *  of the index files will be the md5sums listed in the meta-index;
+ *  otherwise, the expected hashsums will be "" (causing the
+ *  authentication of the index files to be bypassed).
+ */
+class APT_HIDDEN pkgAcqMetaIndex : public pkgAcqMetaBase
+{
+   void * const d;
+   protected:
+   IndexTarget const DetachedSigTarget;
+
+   /** \brief delayed constructor */
+   void Init(std::string const &URIDesc, std::string const &ShortDesc);
+
+   public:
+   virtual std::string DescURI() const APT_OVERRIDE;
+
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+
+   /** \brief Create a new pkgAcqMetaIndex. */
+   pkgAcqMetaIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+		   IndexTarget const &DataTarget, IndexTarget const &DetachedSigTarget) APT_NONNULL(2, 3);
+   virtual ~pkgAcqMetaIndex();
+
+   friend class pkgAcqMetaSig;
+};
+									/*}}}*/
+/** \brief An acquire item that downloads the detached signature	{{{
+ *  of a meta-index (Release) file, then queues up the release
+ *  file itself.
+ *
+ *  \todo Why protected members?
+ *
+ *  \sa pkgAcqMetaIndex
+ */
+class APT_HIDDEN pkgAcqMetaSig : public pkgAcqTransactionItem
+{
+   void * const d;
+
+   pkgAcqMetaIndex * const MetaIndex;
+
+   /** \brief The file we use to verify the MetaIndexFile with (not always set!) */
+   std::string MetaIndexFileSignature;
+
+   protected:
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   public:
+   virtual bool HashesRequired() const APT_OVERRIDE { return false; }
+
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+
+   /** \brief Create a new pkgAcqMetaSig. */
+   pkgAcqMetaSig(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+	 IndexTarget const &Target, pkgAcqMetaIndex * const MetaIndex) APT_NONNULL(2, 3, 5);
+   virtual ~pkgAcqMetaSig();
+};
+									/*}}}*/
+/** \brief An item repsonsible for downloading clearsigned metaindexes	{{{*/
+class APT_HIDDEN pkgAcqMetaClearSig : public pkgAcqMetaIndex
+{
+   void * const d;
+   IndexTarget const DetachedDataTarget;
+
+ public:
+   /** \brief A package-system-specific parser for the meta-index file. */
+   metaIndex *MetaIndexParser;
+   metaIndex *LastMetaIndexParser;
+
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual bool VerifyDone(std::string const &Message, pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Finished() APT_OVERRIDE;
+
+   /** \brief Starts downloading the individual index files.
     *
-    *  \param ExpectedHash The list file's MD5 signature.
+    *  \param verify If \b true, only indices whose expected hashsum
+    *  can be determined from the meta-index will be downloaded, and
+    *  the hashsums of indices will be checked (reporting
+    *  #StatAuthError if there is a mismatch).  If verify is \b false,
+    *  no hashsum checking will be performed.
     */
-   pkgAcqSubIndex(pkgAcquire *Owner, std::string const &URI,std::string const &URIDesc,
-		   std::string const &ShortDesc, HashString const &ExpectedHash);
+   void QueueIndexes(bool const verify);
+
+   /** \brief Create a new pkgAcqMetaClearSig. */
+   pkgAcqMetaClearSig(pkgAcquire * const Owner,
+		IndexTarget const &ClearsignedTarget,
+		IndexTarget const &DetachedDataTarget,
+		IndexTarget const &DetachedSigTarget,
+		metaIndex * const MetaIndexParser);
+   virtual ~pkgAcqMetaClearSig();
+};
+									/*}}}*/
+/** \brief Common base class for all classes that deal with fetching indexes	{{{*/
+class APT_HIDDEN pkgAcqBaseIndex : public pkgAcqTransactionItem
+{
+   void * const d;
+
+ public:
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+
+   pkgAcqBaseIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+                   IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqBaseIndex();
 };
 									/*}}}*/
 /** \brief An item that is responsible for fetching an index file of	{{{
@@ -363,42 +620,34 @@ class pkgAcqSubIndex : public pkgAcquire::Item
  *
  *  \sa pkgAcqIndexDiffs, pkgAcqIndex
  */
-class pkgAcqDiffIndex : public pkgAcquire::Item
+class APT_HIDDEN pkgAcqDiffIndex : public pkgAcqBaseIndex
 {
+   void * const d;
+   std::vector<pkgAcqIndexMergeDiffs*> * diffs;
+
  protected:
    /** \brief If \b true, debugging information will be written to std::clog. */
    bool Debug;
 
-   /** \brief The item that is currently being downloaded. */
-   pkgAcquire::ItemDesc Desc;
-
-   /** \brief The URI of the index file to recreate at our end (either
-    *  by downloading it or by applying partial patches).
-    */
-   std::string RealURI;
-
-   /** \brief The Hash that the real index file should have after
-    *  all patches have been applied.
-    */
-   HashString ExpectedHash;
-
-   /** \brief The index file which will be patched to generate the new
-    *  file.
-    */
-   std::string CurrentPackagesFile;
-
    /** \brief A description of the Packages file (stored in
     *  pkgAcquire::ItemDesc::Description).
     */
    std::string Description;
 
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
+   virtual bool QueueURI(pkgAcquire::ItemDesc &Item) APT_OVERRIDE;
+
+   virtual bool TransactionState(TransactionStates const state) APT_OVERRIDE;
  public:
    // Specialized action members
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size,std::string Md5Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string DescURI() {return RealURI + "Index";};
-   virtual std::string Custom600Headers();
+   virtual void Failed(std::string const &Message, pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI + "Index";};
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string GetMetaKey() const APT_OVERRIDE;
 
    /** \brief Parse the Index file for a set of Packages diffs.
     *
@@ -410,8 +659,7 @@ class pkgAcqDiffIndex : public pkgAcquire::Item
     *  \return \b true if the Index file was successfully parsed, \b
     *  false otherwise.
     */
-   bool ParseDiffIndex(std::string IndexDiffFile);
-   
+   bool ParseDiffIndex(std::string const &IndexDiffFile);
 
    /** \brief Create a new pkgAcqDiffIndex.
     *
@@ -422,14 +670,113 @@ class pkgAcqDiffIndex : public pkgAcquire::Item
     *  \param URIDesc A long description of the list file to download.
     *
     *  \param ShortDesc A short description of the list file to download.
+    */
+   pkgAcqDiffIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+                   IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqDiffIndex();
+ private:
+   APT_HIDDEN void QueueOnIMSHit() const;
+};
+									/*}}}*/
+struct APT_HIDDEN DiffInfo {						/*{{{*/
+   /** The filename of the diff. */
+   std::string file;
+
+   /** The hashes of the file after the diff is applied */
+   HashStringList result_hashes;
+
+   /** The hashes of the diff */
+   HashStringList patch_hashes;
+
+   /** The hashes of the compressed diff */
+   HashStringList download_hashes;
+};
+									/*}}}*/
+/** \brief An item that is responsible for fetching client-merge patches {{{
+ *  that need to be applied to a given package index file.
+ *
+ *  Instead of downloading and applying each patch one by one like its
+ *  sister #pkgAcqIndexDiffs this class will download all patches at once
+ *  and call rred with all the patches downloaded once. Rred will then
+ *  merge and apply them in one go, which should be a lot faster – but is
+ *  incompatible with server-based merges of patches like reprepro can do.
+ *
+ *  \sa pkgAcqDiffIndex, pkgAcqIndex
+ */
+class APT_HIDDEN pkgAcqIndexMergeDiffs : public pkgAcqBaseIndex
+{
+   void * const d;
+
+   protected:
+
+   /** \brief If \b true, debugging output will be written to
+    *  std::clog.
+    */
+   bool Debug;
+
+   /** \brief description of the file being downloaded. */
+   std::string Description;
+
+   /** \brief information about the current patch */
+   struct DiffInfo const patch;
+
+   /** \brief list of all download items for the patches */
+   std::vector<pkgAcqIndexMergeDiffs*> const * const allPatches;
+
+   /** The current status of this patch. */
+   enum DiffState
+   {
+      /** \brief The diff is currently being fetched. */
+      StateFetchDiff,
+
+      /** \brief The diff is currently being applied. */
+      StateApplyDiff,
+
+      /** \brief the work with this diff is done */
+      StateDoneDiff,
+
+      /** \brief something bad happened and fallback was triggered */
+      StateErrorDiff
+   } State;
+
+   public:
+   /** \brief Called when the patch file failed to be downloaded.
+    *
+    *  This method will fall back to downloading the whole index file
+    *  outright; its arguments are ignored.
+    */
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+	 pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI + "Index";};
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
+   /** \brief Create an index merge-diff item.
+    *
+    *  \param Owner The pkgAcquire object that owns this item.
+    *
+    *  \param URI The URI of the package index file being
+    *  reconstructed.
+    *
+    *  \param URIDesc A long description of this item.
+    *
+    *  \param ShortDesc A brief description of this item.
+    *
+    *  \param patch contains infos about the patch this item is supposed
+    *  to download which were read from the index
     *
-    *  \param ExpectedHash The list file's MD5 signature.
+    *  \param allPatches contains all related items so that each item can
+    *  check if it was the last one to complete the download step
     */
-   pkgAcqDiffIndex(pkgAcquire *Owner,std::string URI,std::string URIDesc,
-		   std::string ShortDesc, HashString ExpectedHash);
+   pkgAcqIndexMergeDiffs(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+                         IndexTarget const &Target, DiffInfo const &patch,
+                         std::vector<pkgAcqIndexMergeDiffs*> const * const allPatches) APT_NONNULL(2, 3, 6);
+   virtual ~pkgAcqIndexMergeDiffs();
 };
 									/*}}}*/
-/** \brief An item that is responsible for fetching all the patches	{{{
+/** \brief An item that is responsible for fetching server-merge patches {{{
  *  that need to be applied to a given package index file.
  *
  *  After downloading and applying a single patch, this item will
@@ -440,8 +787,10 @@ class pkgAcqDiffIndex : public pkgAcquire::Item
  *
  *  \sa pkgAcqDiffIndex, pkgAcqIndex
  */
-class pkgAcqIndexDiffs : public pkgAcquire::Item
+class APT_HIDDEN pkgAcqIndexDiffs : public pkgAcqBaseIndex
 {
+   void * const d;
+
    private:
 
    /** \brief Queue up the next diff download.
@@ -453,20 +802,20 @@ class pkgAcqIndexDiffs : public pkgAcquire::Item
     *  \return \b true if an applicable diff was found, \b false
     *  otherwise.
     */
-   bool QueueNextDiff();
+   APT_HIDDEN bool QueueNextDiff();
 
    /** \brief Handle tasks that must be performed after the item
     *  finishes downloading.
     *
-    *  Dequeues the item and checks the resulting file's md5sum
-    *  against ExpectedHash after the last patch was applied.
+    *  Dequeues the item and checks the resulting file's hashsums
+    *  against ExpectedHashes after the last patch was applied.
     *  There is no need to check the md5/sha1 after a "normal" 
     *  patch because QueueNextDiff() will check the sha1 later.
     *
     *  \param allDone If \b true, the file was entirely reconstructed,
     *  and its md5sum is verified. 
     */
-   void Finish(bool allDone=false);
+   APT_HIDDEN void Finish(bool const allDone=false);
 
    protected:
 
@@ -475,21 +824,6 @@ class pkgAcqIndexDiffs : public pkgAcquire::Item
     */
    bool Debug;
 
-   /** \brief A description of the item that is currently being
-    *  downloaded.
-    */
-   pkgAcquire::ItemDesc Desc;
-
-   /** \brief The URI of the package index file that is being
-    *  reconstructed.
-    */
-   std::string RealURI;
-
-   /** \brief The HashSum of the package index file that is being
-    *  reconstructed.
-    */
-   HashString ExpectedHash;
-
    /** A description of the file being downloaded. */
    std::string Description;
 
@@ -503,42 +837,36 @@ class pkgAcqIndexDiffs : public pkgAcquire::Item
     */
    std::vector<DiffInfo> available_patches;
 
-   /** Stop applying patches when reaching that sha1 */
-   std::string ServerSha1;
-
    /** The current status of this patch. */
    enum DiffState
-     {
-	/** \brief The diff is in an unknown state. */
-	 StateFetchUnkown,
-
+   {
 	 /** \brief The diff is currently being fetched. */
 	 StateFetchDiff,
-	 
-	 /** \brief The diff is currently being uncompressed. */
-	 StateUnzipDiff, // FIXME: No longer used
 
 	 /** \brief The diff is currently being applied. */
 	 StateApplyDiff
    } State;
 
    public:
-   
+
    /** \brief Called when the patch file failed to be downloaded.
     *
     *  This method will fall back to downloading the whole index file
     *  outright; its arguments are ignored.
     */
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
 
-   virtual void Done(std::string Message,unsigned long long Size,std::string Md5Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string DescURI() {return RealURI + "Index";};
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Target.URI + "IndexDiffs";};
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
 
    /** \brief Create an index diff item.
     *
     *  After filling in its basic fields, this invokes Finish(true) if
-    *  #diffs is empty, or QueueNextDiff() otherwise.
+    *  \a diffs is empty, or QueueNextDiff() otherwise.
     *
     *  \param Owner The pkgAcquire object that owns this item.
     *
@@ -549,18 +877,14 @@ class pkgAcqIndexDiffs : public pkgAcquire::Item
     *
     *  \param ShortDesc A brief description of this item.
     *
-    *  \param ExpectedHash The expected md5sum of the completely
-    *  reconstructed package index file; the index file will be tested
-    *  against this value when it is entirely reconstructed.
-    *
     *  \param diffs The remaining diffs from the index of diffs.  They
     *  should be ordered so that each diff appears before any diff
     *  that depends on it.
     */
-   pkgAcqIndexDiffs(pkgAcquire *Owner,std::string URI,std::string URIDesc,
-		    std::string ShortDesc, HashString ExpectedHash,
-		    std::string ServerSha1,
-		    std::vector<DiffInfo> diffs=std::vector<DiffInfo>());
+   pkgAcqIndexDiffs(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+                    IndexTarget const &Target,
+		    std::vector<DiffInfo> const &diffs=std::vector<DiffInfo>()) APT_NONNULL(2, 3);
+   virtual ~pkgAcqIndexDiffs();
 };
 									/*}}}*/
 /** \brief An acquire item that is responsible for fetching an index	{{{
@@ -570,357 +894,68 @@ class pkgAcqIndexDiffs : public pkgAcquire::Item
  *
  *  \todo Why does pkgAcqIndex have protected members?
  */
-class pkgAcqIndex : public pkgAcquire::Item
+class APT_HIDDEN pkgAcqIndex : public pkgAcqBaseIndex
 {
-   protected:
+   void * const d;
 
-   /** \brief If \b true, the index file has been decompressed. */
-   bool Decompression;
+   protected:
 
-   /** \brief If \b true, the partially downloaded file will be
-    *  removed when the download completes.
+   /** \brief The stages the method goes through
+    *
+    *  The method first downloads the indexfile, then its decompressed (or
+    *  copied) and verified
     */
-   bool Erase;
+   enum AllStages {
+      STAGE_DOWNLOAD,
+      STAGE_DECOMPRESS_AND_VERIFY,
+   };
+   AllStages Stage;
 
-   /** \brief Verify for correctness by checking if a "Package"
-    *         tag is found in the index. This can be set to
-    *         false for optional index targets
-    *       
-    */
-   // FIXME: instead of a bool it should use a verify string that will
-   //        then be used in the pkgAcqIndex::Done method to ensure that
-   //        the downloaded file contains the expected tag
-   bool Verify;
+   /** \brief Handle what needs to be done when the download is done */
+   void StageDownloadDone(std::string const &Message);
 
-   /** \brief The download request that is currently being
-    *   processed.
+   /** \brief Handle what needs to be done when the decompression/copy is
+    *         done 
     */
-   pkgAcquire::ItemDesc Desc;
+   void StageDecompressDone();
 
-   /** \brief The object that is actually being fetched (minus any
-    *  compression-related extensions).
+   /** \brief If \b set, this partially downloaded file will be
+    *  removed when the download completes.
     */
-   std::string RealURI;
-
-   /** \brief The expected hashsum of the decompressed index file. */
-   HashString ExpectedHash;
+   std::string EraseFileName;
 
    /** \brief The compression-related file extensions that are being
     *  added to the downloaded file one by one if first fails (e.g., "gz bz2").
     */
-   std::string CompressionExtension;
-
-   public:
-   
-   // Specialized action members
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size,std::string Md5Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string Custom600Headers();
-   virtual std::string DescURI() {return Desc.URI;};
-   virtual std::string HashSum() {return ExpectedHash.toStr(); };
-
-   /** \brief Create a pkgAcqIndex.
-    *
-    *  \param Owner The pkgAcquire object with which this item is
-    *  associated.
-    *
-    *  \param URI The URI of the index file that is to be downloaded.
-    *
-    *  \param URIDesc A "URI-style" description of this index file.
-    *
-    *  \param ShortDesc A brief description of this index file.
-    *
-    *  \param ExpectedHash The expected hashsum of this index file.
-    *
-    *  \param compressExt The compression-related extension with which
-    *  this index file should be downloaded, or "" to autodetect
-    *  Compression types can be set with config Acquire::CompressionTypes,
-    *  default is ".lzma" or ".bz2" (if the needed binaries are present)
-    *  fallback is ".gz" or none.
-    */
-   pkgAcqIndex(pkgAcquire *Owner,std::string URI,std::string URIDesc,
-	       std::string ShortDesc, HashString ExpectedHash, 
-	       std::string compressExt="");
-   pkgAcqIndex(pkgAcquire *Owner, struct IndexTarget const * const Target,
-			 HashString const &ExpectedHash, indexRecords const *MetaIndexParser);
-   void Init(std::string const &URI, std::string const &URIDesc, std::string const &ShortDesc);
-};
-									/*}}}*/
-/** \brief An acquire item that is responsible for fetching a		{{{
- *  translated index file.
- *
- *  The only difference from pkgAcqIndex is that transient failures
- *  are suppressed: no error occurs if the translated index file is
- *  missing.
- */
-class pkgAcqIndexTrans : public pkgAcqIndex
-{
-   public:
-  
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual std::string Custom600Headers();
-
-   /** \brief Create a pkgAcqIndexTrans.
-    *
-    *  \param Owner The pkgAcquire object with which this item is
-    *  associated.
-    *
-    *  \param URI The URI of the index file that is to be downloaded.
-    *
-    *  \param URIDesc A "URI-style" description of this index file.
-    *
-    *  \param ShortDesc A brief description of this index file.
-    */
-   pkgAcqIndexTrans(pkgAcquire *Owner,std::string URI,std::string URIDesc,
-		    std::string ShortDesc);
-   pkgAcqIndexTrans(pkgAcquire *Owner, struct IndexTarget const * const Target,
-		    HashString const &ExpectedHash, indexRecords const *MetaIndexParser);
-};
-									/*}}}*/
-/** \brief Information about an index file. */				/*{{{*/
-class IndexTarget
-{
- public:
-   /** \brief A URI from which the index file can be downloaded. */
-   std::string URI;
+   std::string CompressionExtensions;
 
-   /** \brief A description of the index file. */
-   std::string Description;
+   /** \brief The actual compression extension currently used */
+   std::string CurrentCompressionExtension;
 
-   /** \brief A shorter description of the index file. */
-   std::string ShortDesc;
+   /** \brief Do the changes needed to fetch via AptByHash (if needed) */
+   void InitByHashIfNeeded();
 
-   /** \brief The key by which this index file should be
-    *  looked up within the meta signature file.
-    */
-   std::string MetaKey;
-
-   virtual bool IsOptional() const {
-      return false;
-   }
-   virtual bool IsSubIndex() const {
-      return false;
-   }
-};
-									/*}}}*/
-/** \brief Information about an optional index file. */			/*{{{*/
-class OptionalIndexTarget : public IndexTarget
-{
-   virtual bool IsOptional() const {
-      return true;
-   }
-};
-									/*}}}*/
-/** \brief Information about an subindex index file. */			/*{{{*/
-class SubIndexTarget : public IndexTarget
-{
-   virtual bool IsSubIndex() const {
-      return true;
-   }
-};
-									/*}}}*/
-/** \brief Information about an subindex index file. */			/*{{{*/
-class OptionalSubIndexTarget : public OptionalIndexTarget
-{
-   virtual bool IsSubIndex() const {
-      return true;
-   }
-};
-									/*}}}*/
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
 
-/** \brief An acquire item that downloads the detached signature	{{{
- *  of a meta-index (Release) file, then queues up the release
- *  file itself.
- *
- *  \todo Why protected members?
- *
- *  \sa pkgAcqMetaIndex
- */
-class pkgAcqMetaSig : public pkgAcquire::Item
-{
-   protected:
-   /** \brief The last good signature file */
-   std::string LastGoodSig;
-
-   /** \brief The fetch request that is currently being processed. */
-   pkgAcquire::ItemDesc Desc;
-
-   /** \brief The URI of the signature file.  Unlike Desc.URI, this is
-    *  never modified; it is used to determine the file that is being
-    *  downloaded.
-    */
-   std::string RealURI;
-
-   /** \brief The URI of the meta-index file to be fetched after the signature. */
-   std::string MetaIndexURI;
-
-   /** \brief A "URI-style" description of the meta-index file to be
-    *  fetched after the signature.
-    */
-   std::string MetaIndexURIDesc;
-
-   /** \brief A brief description of the meta-index file to be fetched
-    *  after the signature.
-    */
-   std::string MetaIndexShortDesc;
-
-   /** \brief A package-system-specific parser for the meta-index file. */
-   indexRecords* MetaIndexParser;
-
-   /** \brief The index files which should be looked up in the meta-index
-    *  and then downloaded.
-    *
-    *  \todo Why a list of pointers instead of a list of structs?
-    */
-   const std::vector<struct IndexTarget*>* IndexTargets;
+   virtual bool TransactionState(TransactionStates const state) APT_OVERRIDE;
 
    public:
-   
    // Specialized action members
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size,std::string Md5Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string Custom600Headers();
-   virtual std::string DescURI() {return RealURI; };
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Desc.URI;};
+   virtual std::string GetMetaKey() const APT_OVERRIDE;
 
-   /** \brief Create a new pkgAcqMetaSig. */
-   pkgAcqMetaSig(pkgAcquire *Owner,std::string URI,std::string URIDesc, std::string ShortDesc,
-		 std::string MetaIndexURI, std::string MetaIndexURIDesc, std::string MetaIndexShortDesc,
-		 const std::vector<struct IndexTarget*>* IndexTargets,
-		 indexRecords* MetaIndexParser);
-   virtual ~pkgAcqMetaSig();
-};
-									/*}}}*/
-/** \brief An item that is responsible for downloading the meta-index	{{{
- *  file (i.e., Release) itself and verifying its signature.
- *
- *  Once the download and verification are complete, the downloads of
- *  the individual index files are queued up using pkgAcqDiffIndex.
- *  If the meta-index file had a valid signature, the expected hashsums
- *  of the index files will be the md5sums listed in the meta-index;
- *  otherwise, the expected hashsums will be "" (causing the
- *  authentication of the index files to be bypassed).
- */
-class pkgAcqMetaIndex : public pkgAcquire::Item
-{
-   protected:
-   /** \brief The fetch command that is currently being processed. */
-   pkgAcquire::ItemDesc Desc;
-
-   /** \brief The URI that is actually being downloaded; never
-    *  modified by pkgAcqMetaIndex.
-    */
-   std::string RealURI;
-
-   /** \brief The file in which the signature for this index was stored.
-    *
-    *  If empty, the signature and the md5sums of the individual
-    *  indices will not be checked.
-    */
-   std::string SigFile;
-
-   /** \brief The index files to download. */
-   const std::vector<struct IndexTarget*>* IndexTargets;
-
-   /** \brief The parser for the meta-index file. */
-   indexRecords* MetaIndexParser;
-
-   /** \brief If \b true, the index's signature is currently being verified.
-    */
-   bool AuthPass;
-   // required to deal gracefully with problems caused by incorrect ims hits
-   bool IMSHit; 
-
-   /** \brief Check that the release file is a release file for the
-    *  correct distribution.
-    *
-    *  \return \b true if no fatal errors were encountered.
-    */
-   bool VerifyVendor(std::string Message);
-
-   /** \brief Called when a file is finished being retrieved.
-    *
-    *  If the file was not downloaded to DestFile, a copy process is
-    *  set up to copy it to DestFile; otherwise, Complete is set to \b
-    *  true and the file is moved to its final location.
-    *
-    *  \param Message The message block received from the fetch
-    *  subprocess.
-    */
-   void RetrievalDone(std::string Message);
-
-   /** \brief Called when authentication succeeded.
-    *
-    *  Sanity-checks the authenticated file, queues up the individual
-    *  index files for download, and saves the signature in the lists
-    *  directory next to the authenticated list file.
-    *
-    *  \param Message The message block received from the fetch
-    *  subprocess.
-    */
-   void AuthDone(std::string Message);
-
-   /** \brief Starts downloading the individual index files.
-    *
-    *  \param verify If \b true, only indices whose expected hashsum
-    *  can be determined from the meta-index will be downloaded, and
-    *  the hashsums of indices will be checked (reporting
-    *  #StatAuthError if there is a mismatch).  If verify is \b false,
-    *  no hashsum checking will be performed.
-    */
-   void QueueIndexes(bool verify);
-   
-   public:
-   
-   // Specialized action members
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size, std::string Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string Custom600Headers();
-   virtual std::string DescURI() {return RealURI; };
-
-   /** \brief Create a new pkgAcqMetaIndex. */
-   pkgAcqMetaIndex(pkgAcquire *Owner,
-		   std::string URI,std::string URIDesc, std::string ShortDesc,
-		   std::string SigFile,
-		   const std::vector<struct IndexTarget*>* IndexTargets,
-		   indexRecords* MetaIndexParser);
-};
-									/*}}}*/
-/** \brief An item repsonsible for downloading clearsigned metaindexes	{{{*/
-class pkgAcqMetaClearSig : public pkgAcqMetaIndex
-{
-   /** \brief The URI of the meta-index file for the detached signature */
-   std::string MetaIndexURI;
-
-   /** \brief A "URI-style" description of the meta-index file */
-   std::string MetaIndexURIDesc;
-
-   /** \brief A brief description of the meta-index file */
-   std::string MetaIndexShortDesc;
+   pkgAcqIndex(pkgAcquire * const Owner, pkgAcqMetaClearSig * const TransactionManager,
+               IndexTarget const &Target) APT_NONNULL(2, 3);
+   virtual ~pkgAcqIndex();
 
-   /** \brief The URI of the detached meta-signature file if the clearsigned one failed. */
-   std::string MetaSigURI;
-
-   /** \brief A "URI-style" description of the meta-signature file */
-   std::string MetaSigURIDesc;
-
-   /** \brief A brief description of the meta-signature file */
-   std::string MetaSigShortDesc;
-
-public:
-   void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual std::string Custom600Headers();
-
-   /** \brief Create a new pkgAcqMetaClearSig. */
-   pkgAcqMetaClearSig(pkgAcquire *Owner,
-		std::string const &URI, std::string const &URIDesc, std::string const &ShortDesc,
-		std::string const &MetaIndexURI, std::string const &MetaIndexURIDesc, std::string const &MetaIndexShortDesc,
-		std::string const &MetaSigURI, std::string const &MetaSigURIDesc, std::string const &MetaSigShortDesc,
-		const std::vector<struct IndexTarget*>* IndexTargets,
-		indexRecords* MetaIndexParser);
-   virtual ~pkgAcqMetaClearSig();
+   private:
+   APT_HIDDEN void Init(std::string const &URI, std::string const &URIDesc,
+             std::string const &ShortDesc);
 };
 									/*}}}*/
 /** \brief An item that is responsible for fetching a package file.	{{{
@@ -930,13 +965,15 @@ public:
  */
 class pkgAcqArchive : public pkgAcquire::Item
 {
+   void * const d;
+
+   bool LocalSource;
+   HashStringList ExpectedHashes;
+
    protected:
    /** \brief The package version being fetched. */
    pkgCache::VerIterator Version;
 
-   /** \brief The fetch command that is currently being processed. */
-   pkgAcquire::ItemDesc Desc;
-
    /** \brief The list of sources from which to pick archives to
     *  download this package from.
     */
@@ -947,9 +984,6 @@ class pkgAcqArchive : public pkgAcquire::Item
     */
    pkgRecords *Recs;
 
-   /** \brief The hashsum of this package. */
-   HashString ExpectedHash;
-
    /** \brief A location in which the actual filename of the package
     *  should be stored.
     */
@@ -968,22 +1002,26 @@ class pkgAcqArchive : public pkgAcquire::Item
    /** \brief \b true if this version file is being downloaded from a
     *  trusted source.
     */
-   bool Trusted; 
+   bool Trusted;
 
    /** \brief Queue up the next available file for this version. */
    bool QueueNext();
-   
+
+   /** \brief Get the full pathname of the final file for the current URI */
+   virtual std::string GetFinalFilename() const APT_OVERRIDE;
+
    public:
-   
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size,std::string Hash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string DescURI() {return Desc.URI;};
-   virtual std::string ShortDesc() {return Desc.ShortDesc;};
-   virtual void Finished();
-   virtual std::string HashSum() {return ExpectedHash.toStr(); };
-   virtual bool IsTrusted();
-   
+
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &Hashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE;
+   virtual std::string ShortDesc() const APT_OVERRIDE;
+   virtual void Finished() APT_OVERRIDE;
+   virtual bool IsTrusted() const APT_OVERRIDE;
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
    /** \brief Create a new pkgAcqArchive.
     *
     *  \param Owner The pkgAcquire object with which this item is
@@ -1002,9 +1040,125 @@ class pkgAcqArchive : public pkgAcquire::Item
     *  basename in the constructor, and filled in with a fully
     *  qualified filename once the download finishes.
     */
-   pkgAcqArchive(pkgAcquire *Owner,pkgSourceList *Sources,
-		 pkgRecords *Recs,pkgCache::VerIterator const &Version,
+   pkgAcqArchive(pkgAcquire * const Owner,pkgSourceList * const Sources,
+		 pkgRecords * const Recs,pkgCache::VerIterator const &Version,
 		 std::string &StoreFilename);
+   virtual ~pkgAcqArchive();
+};
+									/*}}}*/
+/** \brief Retrieve the changelog for the given version			{{{
+ *
+ *  Downloads the changelog to a temporary file it will also remove again
+ *  while it is deconstructed or downloads it to a named location.
+ */
+class pkgAcqChangelog : public pkgAcquire::Item
+{
+   class Private;
+   Private * const d;
+   std::string TemporaryDirectory;
+   std::string const SrcName;
+   std::string const SrcVersion;
+
+   public:
+   // we will never have hashes for changelogs.
+   // If you need verified ones, download the deb and extract the changelog.
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE { return HashStringList(); }
+   virtual bool HashesRequired() const APT_OVERRIDE { return false; }
+
+   // Specialized action members
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &CalcHashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Desc.URI;};
+
+   /** returns the URI to the changelog of this version
+    *
+    * @param Ver is the version to get the changelog for
+    * @return the URI which will be used to acquire the changelog
+    */
+   static std::string URI(pkgCache::VerIterator const &Ver);
+
+   /** returns the URI to the changelog of this version
+    *
+    *  \param Rls is the Release file the package comes from
+    *  \param Component in which the package resides, can be empty
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    * @return the URI which will be used to acquire the changelog
+    */
+   static std::string URI(pkgCache::RlsFileIterator const &Rls,
+	 char const * const Component, char const * const SrcName,
+	 char const * const SrcVersion);
+
+   /** returns the URI to the changelog of this version
+    *
+    *  \param Template URI where @CHANGEPATH@ has to be filled in
+    *  \param Component in which the package resides, can be empty
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    * @return the URI which will be used to acquire the changelog
+    */
+   static std::string URI(std::string const &Template,
+	 char const * const Component, char const * const SrcName,
+	 char const * const SrcVersion);
+
+   /** returns the URI template for this release file
+    *
+    *  \param Rls is a Release file
+    * @return the URI template to use for this release file
+    */
+   static std::string URITemplate(pkgCache::RlsFileIterator const &Rls);
+
+   /** \brief Create a new pkgAcqChangelog object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *  \param Ver is the version to get the changelog for
+    *  \param DestDir The directory the file should be downloaded into.
+    *  Will be an autocreated (and cleaned up) temporary directory if not set.
+    *  \param DestFilename The filename the file should have in #DestDir
+    *  Defaults to sourcepackagename.changelog if not set.
+    */
+   pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::VerIterator const &Ver,
+	 std::string const &DestDir="", std::string const &DestFilename="");
+
+   /** \brief Create a new pkgAcqChangelog object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *  \param Rls is the Release file the package comes from
+    *  \param Component in which the package resides, can be empty
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    *  \param DestDir The directory the file should be downloaded into.
+    *  Will be an autocreated (and cleaned up) temporary directory if not set.
+    *  \param DestFilename The filename the file should have in #DestDir
+    *  Defaults to sourcepackagename.changelog if not set.
+    */
+   pkgAcqChangelog(pkgAcquire * const Owner, pkgCache::RlsFileIterator const &Rls,
+	 char const * const Component, char const * const SrcName, char const * const SrcVersion,
+	 std::string const &DestDir="", std::string const &DestFilename="");
+
+   /** \brief Create a new pkgAcqChangelog object.
+    *
+    *  \param Owner The pkgAcquire object with which this object is
+    *  associated.
+    *  \param URI is to be used to get the changelog
+    *  \param SrcName is the source package name
+    *  \param SrcVersion is the source package version
+    *  \param DestDir The directory the file should be downloaded into.
+    *  Will be an autocreated (and cleaned up) temporary directory if not set.
+    *  \param DestFilename The filename the file should have in #DestDir
+    *  Defaults to sourcepackagename.changelog if not set.
+    */
+   pkgAcqChangelog(pkgAcquire * const Owner, std::string const &URI,
+	 char const * const SrcName, char const * const SrcVersion,
+	 std::string const &DestDir="", std::string const &DestFilename="");
+
+   virtual ~pkgAcqChangelog();
+
+private:
+   APT_HIDDEN void Init(std::string const &DestDir, std::string const &DestFilename);
 };
 									/*}}}*/
 /** \brief Retrieve an arbitrary file to the current directory.		{{{
@@ -1015,29 +1169,27 @@ class pkgAcqArchive : public pkgAcquire::Item
  */
 class pkgAcqFile : public pkgAcquire::Item
 {
-   /** \brief The currently active download process. */
-   pkgAcquire::ItemDesc Desc;
-
-   /** \brief The hashsum of the file to download, if it is known. */
-   HashString ExpectedHash;
+   void * const d;
 
    /** \brief How many times to retry the download, set from
     *  Acquire::Retries.
     */
    unsigned int Retries;
-   
+
    /** \brief Should this file be considered a index file */
    bool IsIndexFile;
 
+   HashStringList const ExpectedHashes;
    public:
-   
+   virtual HashStringList GetExpectedHashes() const APT_OVERRIDE;
+   virtual bool HashesRequired() const APT_OVERRIDE;
+
    // Specialized action members
-   virtual void Failed(std::string Message,pkgAcquire::MethodConfig *Cnf);
-   virtual void Done(std::string Message,unsigned long long Size,std::string CalcHash,
-		     pkgAcquire::MethodConfig *Cnf);
-   virtual std::string DescURI() {return Desc.URI;};
-   virtual std::string HashSum() {return ExpectedHash.toStr(); };
-   virtual std::string Custom600Headers();
+   virtual void Failed(std::string const &Message,pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual void Done(std::string const &Message, HashStringList const &CalcHashes,
+		     pkgAcquire::MethodConfig const * const Cnf) APT_OVERRIDE;
+   virtual std::string DescURI() const APT_OVERRIDE {return Desc.URI;};
+   virtual std::string Custom600Headers() const APT_OVERRIDE;
 
    /** \brief Create a new pkgAcqFile object.
     *
@@ -1046,8 +1198,8 @@ class pkgAcqFile : public pkgAcquire::Item
     *
     *  \param URI The URI to download.
     *
-    *  \param Hash The hashsum of the file to download, if it is known;
-    *  otherwise "".
+    *  \param Hashes The hashsums of the file to download, if they are known;
+    *  otherwise empty list.
     *
     *  \param Size The size of the file to download, if it is known;
     *  otherwise 0.
@@ -1064,16 +1216,17 @@ class pkgAcqFile : public pkgAcquire::Item
     *  \param IsIndexFile The file is considered a IndexFile and cache-control
     *                     headers like "cache-control: max-age=0" are send
     *
-    * If DestFilename is empty, download to DestDir/<basename> if
-    * DestDir is non-empty, $CWD/<basename> otherwise.  If
+    * If DestFilename is empty, download to DestDir/\<basename\> if
+    * DestDir is non-empty, $CWD/\<basename\> otherwise.  If
     * DestFilename is NOT empty, DestDir is ignored and DestFilename
     * is the absolute name to which the file should be downloaded.
     */
 
-   pkgAcqFile(pkgAcquire *Owner, std::string URI, std::string Hash, unsigned long long Size,
-	      std::string Desc, std::string ShortDesc,
-	      const std::string &DestDir="", const std::string &DestFilename="",
-	      bool IsIndexFile=false);
+   pkgAcqFile(pkgAcquire * const Owner, std::string const &URI, HashStringList const &Hashes, unsigned long long const Size,
+	      std::string const &Desc, std::string const &ShortDesc,
+	      std::string const &DestDir="", std::string const &DestFilename="",
+	      bool const IsIndexFile=false);
+   virtual ~pkgAcqFile();
 };
 									/*}}}*/
 /** @} */