ensure valid or remove destination file in file method

[apt.git] / methods / file.cc

diff --git a/methods/file.cc b/methods/file.cc
index 353e54bd5fe5ea6c6eb10f30124fc11a39d98cdf..5d5fffa67b289399165b53207a2575b98e263a37 100644 (file)
--- a/methods/file.cc
+++ b/methods/file.cc
@@ -48,8 +48,24 @@ bool FileMethod::Fetch(FetchItem *Itm)
    if (Get.Host.empty() == false)
       return _error->Error(_("Invalid URI, local URIS must not start with //"));
 
-   // See if the file exists
    struct stat Buf;
+   // deal with destination files which might linger around
+   if (lstat(Itm->DestFile.c_str(), &Buf) == 0)
+   {
+      if ((Buf.st_mode & S_IFREG) != 0)
+      {
+        if (Itm->LastModified == Buf.st_mtime && Itm->LastModified != 0)
+        {
+           HashStringList const hsl = Itm->ExpectedHashes;
+           if (Itm->ExpectedHashes.VerifyFile(File))
+              Res.IMSHit = true;
+        }
+      }
+   }
+   if (Res.IMSHit != true)
+      unlink(Itm->DestFile.c_str());
+
+   // See if the file exists
    if (stat(File.c_str(),&Buf) == 0)
    {
       Res.Size = Buf.st_size;
@@ -65,6 +81,8 @@ bool FileMethod::Fetch(FetchItem *Itm)
    }
 
    // See if the uncompressed file exists and reuse it
+   FetchResult AltRes;
+   AltRes.Filename.clear();
    std::vector<std::string> extensions = APT::Configuration::getCompressorExtensions();
    for (std::vector<std::string>::const_iterator ext = extensions.begin(); ext != extensions.end(); ++ext)
    {
@@ -73,29 +91,33 @@ bool FileMethod::Fetch(FetchItem *Itm)
         std::string const unfile = File.substr(0, File.length() - ext->length() - 1);
         if (stat(unfile.c_str(),&Buf) == 0)
         {
-           FetchResult AltRes;
            AltRes.Size = Buf.st_size;
            AltRes.Filename = unfile;
            AltRes.LastModified = Buf.st_mtime;
            AltRes.IMSHit = false;
            if (Itm->LastModified == Buf.st_mtime && Itm->LastModified != 0)
               AltRes.IMSHit = true;
-
-           URIDone(Res,&AltRes);
-           return true;
+           break;
         }
         // no break here as we could have situations similar to '.gz' vs '.tar.gz' here
       }
    }
 
-   if (Res.Filename.empty() == true)
+   if (Res.Filename.empty() == false)
+   {
+      Hashes Hash(Itm->ExpectedHashes);
+      FileFd Fd(Res.Filename, FileFd::ReadOnly);
+      Hash.AddFD(Fd);
+      Res.TakeHashes(Hash);
+   }
+
+   if (AltRes.Filename.empty() == false)
+      URIDone(Res,&AltRes);
+   else if (Res.Filename.empty() == false)
+      URIDone(Res);
+   else
       return _error->Error(_("File not found"));
 
-   Hashes Hash(Itm->ExpectedHashes);
-   FileFd Fd(Res.Filename, FileFd::ReadOnly);
-   Hash.AddFD(Fd);
-   Res.TakeHashes(Hash);
-   URIDone(Res);
    return true;
 }
                                                                        /*}}}*/