enable FileFd to guess the compressor based on the filename if requested or

to search for compressed silbings of the given filename and use this guessing
instead of hardcoding Gzip compression

2 files changed, 123 insertions, 20 deletions

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index d5e7192e3..1cb3fab1e 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -24,6 +24,7 @@
 #include <apt-pkg/strutl.h>
 #include <apt-pkg/error.h>
 #include <apt-pkg/sptr.h>
+#include <apt-pkg/aptconfiguration.h>
 #include <apt-pkg/configuration.h>
 
 #include <cstdlib>
@@ -725,6 +726,11 @@ bool FileFd::Open(string FileName,OpenMode Mode,CompressMode Compress, unsigned
    Close();
    Flags = AutoClose;
 
+   if (Compress == Auto && (Mode & WriteOnly) == WriteOnly)
+      return _error->Error("Autodetection on %s only works in ReadOnly openmode!", FileName.c_str());
+   if ((Mode & WriteOnly) != WriteOnly && (Mode & (Atomic | Create | Empty | Exclusive)) != 0)
+      return _error->Error("ReadOnly mode for %s doesn't accept additional flags!", FileName.c_str());
+
    int fileflags = 0;
 #define if_FLAGGED_SET(FLAG, MODE) if ((Mode & FLAG) == FLAG) fileflags |= MODE
    if_FLAGGED_SET(ReadWrite, O_RDWR);
@@ -738,6 +744,70 @@ bool FileFd::Open(string FileName,OpenMode Mode,CompressMode Compress, unsigned
    if_FLAGGED_SET(Empty, O_TRUNC);
 #undef if_FLAGGED_SET
 
+   // FIXME: Denote inbuilt compressors somehow - as we don't need to have the binaries for them
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   if (Compress == Auto)
+   {
+      Compress = None;
+      for (; compressor != compressors.end(); ++compressor)
+      {
+	 std::string file = std::string(FileName).append(compressor->Extension);
+	 if (FileExists(file) == false)
+	    continue;
+	 FileName = file;
+	 if (compressor->Binary == ".")
+	    Compress = None;
+	 else
+	    Compress = Extension;
+	 break;
+      }
+   }
+   else if (Compress == Extension)
+   {
+      Compress = None;
+      std::string ext = flExtension(FileName);
+      if (ext != FileName)
+      {
+	 ext = "." + ext;
+	 for (; compressor != compressors.end(); ++compressor)
+	    if (ext == compressor->Extension)
+	       break;
+      }
+   }
+   else if (Compress != None)
+   {
+      std::string name;
+      switch (Compress)
+      {
+      case Gzip: name = "gzip"; break;
+      case Bzip2: name = "bzip2"; break;
+      case Lzma: name = "lzma"; break;
+      case Xz: name = "xz"; break;
+      default: return _error->Error("Can't find a match for specified compressor mode for file %s", FileName.c_str());
+      }
+      for (; compressor != compressors.end(); ++compressor)
+	 if (compressor->Name == name)
+	    break;
+      if (compressor == compressors.end() && name != "gzip")
+	 return _error->Error("Can't find a configured compressor %s for file %s", name.c_str(), FileName.c_str());
+   }
+
+   // if we have them, use inbuilt compressors instead of forking
+   if (compressor != compressors.end())
+   {
+      if (compressor->Name == "gzip")
+      {
+	 Compress = Gzip;
+	 compressor = compressors.end();
+      }
+      else if (compressor->Name == "." || Compress == None)
+      {
+	 Compress = None;
+	 compressor = compressors.end();
+      }
+   }
+
    if ((Mode & Atomic) == Atomic)
    {
       Flags |= Replace;
@@ -757,18 +827,27 @@ bool FileFd::Open(string FileName,OpenMode Mode,CompressMode Compress, unsigned
 	 unlink(FileName.c_str());
    }
 
-   if (TemporaryFileName.empty() == false)
-      iFd = open(TemporaryFileName.c_str(), fileflags, Perms);
-   else
-      iFd = open(FileName.c_str(), fileflags, Perms);
+   if (compressor != compressors.end())
+   {
+      if ((Mode & ReadWrite) == ReadWrite)
+	 _error->Error("External compressors like %s do not support readwrite mode for file %s", compressor->Name.c_str(), FileName.c_str());
 
-   if (iFd != -1 && Compress == Gzip)
+      _error->Error("Forking external compressor %s is not implemented for %s", compressor->Name.c_str(), FileName.c_str());
+   }
+   else
    {
-      gz = gzdopen (iFd, "r");
-      if (gz == NULL)
+      if (TemporaryFileName.empty() == false)
+	 iFd = open(TemporaryFileName.c_str(), fileflags, Perms);
+      else
+	 iFd = open(FileName.c_str(), fileflags, Perms);
+
+      if (iFd != -1)
       {
-	 close (iFd);
-	 iFd = -1;
+	 if (OpenInternDescriptor(Mode, Compress) == false)
+	 {
+	    close (iFd);
+	    iFd = -1;
+	 }
       }
    }
 
@@ -788,18 +867,34 @@ bool FileFd::OpenDescriptor(int Fd, OpenMode Mode, CompressMode Compress, bool A
    Close();
    Flags = (AutoClose) ? FileFd::AutoClose : 0;
    iFd = Fd;
-   if (Mode == ReadOnlyGzip) {
-      gz = gzdopen (iFd, "r");
-      if (gz == NULL) {
-	 if (AutoClose)
-	    close (iFd);
-	 return _error->Errno("gzdopen",_("Could not open file descriptor %d"),
-			      Fd);
-      }
+   if (OpenInternDescriptor(Mode, Compress) == false)
+   {
+      if (AutoClose)
+	 close (iFd);
+      return _error->Errno("gzdopen",_("Could not open file descriptor %d"), Fd);
    }
    this->FileName = "";
    return true;
 }
+bool FileFd::OpenInternDescriptor(OpenMode Mode, CompressMode Compress)
+{
+   if (Compress == None)
+      return true;
+   else if (Compress == Gzip)
+   {
+      if ((Mode & ReadWrite) == ReadWrite)
+	 gz = gzdopen(iFd, "r+");
+      else if ((Mode & WriteOnly) == WriteOnly)
+	 gz = gzdopen(iFd, "w");
+      else
+	 gz = gzdopen (iFd, "r");
+      if (gz == NULL)
+	 return false;
+   }
+   else
+      return false;
+   return true;
+}
 									/*}}}*/
 // FileFd::~File - Closes the file					/*{{{*/
 // ---------------------------------------------------------------------
diff --git a/apt-pkg/contrib/fileutl.h b/apt-pkg/contrib/fileutl.h
index fa8f92272..59a9d97e3 100644
--- a/apt-pkg/contrib/fileutl.h
+++ b/apt-pkg/contrib/fileutl.h
@@ -61,7 +61,7 @@ class FileFd
 	ReadOnlyGzip,
 	WriteAtomic = ReadWrite | Create | Atomic
    };
-   enum CompressMode { Auto, None, Gzip, Bzip2, Lzma, Xz };
+   enum CompressMode { Auto = 'A', None = 'N', Extension = 'E', Gzip = 'G', Bzip2 = 'B', Lzma = 'L', Xz = 'X' };
    
    inline bool Read(void *To,unsigned long long Size,bool AllowEof)
    {
@@ -94,7 +94,7 @@ class FileFd
    }
 
    bool Open(std::string FileName,OpenMode Mode,CompressMode Compress,unsigned long Perms = 0666);
-   inline bool Open(std::string const &FileName,OpenMode Mode,unsigned long Perms = 0666) {
+   inline bool Open(std::string const &FileName,OpenMode Mode, unsigned long Perms = 0666) {
       return Open(FileName, Mode, None, Perms);
    };
    bool OpenDescriptor(int Fd, OpenMode Mode, CompressMode Compress, bool AutoClose=false);
@@ -118,11 +118,19 @@ class FileFd
    FileFd(std::string FileName,OpenMode Mode,unsigned long Perms = 0666) : iFd(-1), 
             Flags(0), gz(NULL)
    {
-      Open(FileName,Mode,Perms);
+      Open(FileName,Mode, None, Perms);
+   };
+   FileFd(std::string FileName,OpenMode Mode, CompressMode Compress, unsigned long Perms = 0666) :
+	    iFd(-1), Flags(0), gz(NULL)
+   {
+      Open(FileName,Mode, Compress, Perms);
    };
    FileFd(int Fd = -1) : iFd(Fd), Flags(AutoClose), gz(NULL) {};
    FileFd(int Fd,bool) : iFd(Fd), Flags(0), gz(NULL) {};
    virtual ~FileFd();
+
+   private:
+   bool OpenInternDescriptor(OpenMode Mode, CompressMode Compress);
 };
 
 bool RunScripts(const char *Cnf);