OSX/libsecurity_transform/lib/StreamSource.cpp

   1 #include "StreamSource.h"
   2 #include <string>
   3 #include "misc.h"
   4 #include "SecCFRelease.h"
   5
   6 using namespace std;
   7
   8 CFStringRef gStreamSourceName = CFSTR("StreamSource");
   9
  10 const CFIndex kMaximumSize = 2048;
  11
  12 StreamSource::StreamSource(CFReadStreamRef input, Transform* transform, CFStringRef name)
  13         : Source(gStreamSourceName, transform, name),
  14         mReadStream(input),
  15         mReading(dispatch_group_create())
  16 {
  17         dispatch_group_enter(mReading);
  18         CFRetainSafe(mReadStream);
  19 }
  20
  21 void StreamSource::BackgroundActivate()
  22 {
  23         CFIndex result = 0;
  24
  25         do
  26         {
  27                 // make a buffer big enough to handle the object
  28                 // NOTE: allocating this on the stack and letting CFDataCreate copy it is _faster_ then malloc and CFDataCreateWithBytes(..., kCFAllactorMalloc) by a fair margin.   At least for 2K chunks.   Retest if changing the size.
  29                 UInt8 buffer[kMaximumSize];
  30
  31                 result = CFReadStreamRead(mReadStream, buffer, kMaximumSize);
  32
  33                 if (result > 0) // was data returned?
  34                 {
  35                         // make the data and send it to the transform
  36                         CFDataRef data = CFDataCreate(NULL, buffer, result);
  37
  38                         CFErrorRef error = mDestination->SetAttribute(mDestinationName, data);
  39
  40                         CFReleaseNull(data);
  41
  42                         if (error != NULL) // we have a problem, there was probably an abort on the chain
  43                         {
  44                                 return; // quiesce the source
  45                         }
  46                 }
  47         } while (result > 0);
  48
  49         if (result < 0)
  50         {
  51                 // we got an error!
  52                 CFErrorRef error = CFReadStreamCopyError(mReadStream);
  53                 mDestination->SetAttribute(mDestinationName, error);
  54                 if (error)
  55                 {
  56                         // NOTE: CF doesn't always tell us about this error.   Arguably it could be better to
  57                         // "invent" a generic error, but it is a hard argument that we want to crash in CFReleaseNull(NULL)...
  58                         CFReleaseNull(error);
  59                 }
  60         }
  61         else
  62         {
  63                 // send an EOS
  64                 mDestination->SetAttribute(mDestinationName, NULL); // end of stream
  65         }
  66 }
  67
  68 void StreamSource::DoActivate()
  69 {
  70         CFRetainSafe(mDestination->GetCFObject());
  71         dispatch_group_async(mReading, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
  72                 this->BackgroundActivate();
  73                 CFReleaseSafe(mDestination->GetCFObject());
  74         });
  75         dispatch_group_leave(mReading);
  76 }
  77
  78 void StreamSource::Finalize()
  79 {
  80         dispatch_group_notify(mReading, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
  81                 delete this;
  82         });
  83 }
  84
  85 StreamSource::~StreamSource()
  86 {
  87         CFReleaseNull(mReadStream);
  88         mReadStream = NULL;
  89         dispatch_release(mReading);
  90         mReading = NULL;
  91 }
  92
  93
  94 Boolean StreamSource::Equal(const CoreFoundationObject* object)
  95 {
  96         // not equal if we are not the same object
  97         if (Source::Equal(object))
  98         {
  99                 const StreamSource* ss = (StreamSource*) object;
 100                 return CFEqual(ss->mReadStream, mReadStream);
 101         }
 102
 103         return false;
 104 }
 105
 106
 107
 108 CFTypeRef StreamSource::Make(CFReadStreamRef input, Transform* transform, CFStringRef name)
 109 {
 110         return CoreFoundationHolder::MakeHolder(gInternalCFObjectName, new StreamSource(input, transform, name));
 111 }
 112
 113
 114
 115 string StreamSource::DebugDescription()
 116 {
 117         string result = Source::DebugDescription() + ": Stream ";
 118
 119         char buffer[256];
 120         snprintf(buffer, sizeof(buffer), "(mReadStream = %p)", mReadStream);
 121
 122         result += buffer;
 123
 124         return result;
 125 }