* apt-pkg/contrib/fileutl.{h,cc}:

  - Add support for transparent reading of gzipped files.
  - Link against zlib (in apt-pkg/makefile) and add zlib build dependency.

2 files changed, 47 insertions, 9 deletions

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index da32983f1..11a9e7f7b 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -11,6 +11,7 @@
    Most of this source is placed in the Public Domain, do with it what 
    you will
    It was originally written by Jason Gunthorpe <jgg@debian.org>.
+   FileFd gzip support added by Martin Pitt <martin.pitt@canonical.com>
    
    The exception is RunScripts() it is under the GPLv2
 
@@ -603,6 +604,13 @@ bool FileFd::Open(string FileName,OpenMode Mode, unsigned long Perms)
    {
       case ReadOnly:
       iFd = open(FileName.c_str(),O_RDONLY);
+      if (iFd > 0 && FileName.compare(FileName.size()-3, 3, ".gz") == 0) {
+	  gz = gzdopen (iFd, "r");
+	  if (gz == NULL) {
+	      close (iFd);
+	      iFd = -1;
+	  }
+      }
       break;
       
       case WriteEmpty:
@@ -658,7 +666,10 @@ bool FileFd::Read(void *To,unsigned long Size,unsigned long *Actual)
    
    do
    {
-      Res = read(iFd,To,Size);
+      if (gz != NULL)
+         Res = gzread(gz,To,Size);
+      else
+         Res = read(iFd,To,Size);
       if (Res < 0 && errno == EINTR)
 	 continue;
       if (Res < 0)
@@ -697,7 +708,10 @@ bool FileFd::Write(const void *From,unsigned long Size)
    errno = 0;
    do
    {
-      Res = write(iFd,From,Size);
+      if (gz != NULL)
+         Res = gzwrite(gz,From,Size);
+      else
+         Res = write(iFd,From,Size);
       if (Res < 0 && errno == EINTR)
 	 continue;
       if (Res < 0)
@@ -723,7 +737,12 @@ bool FileFd::Write(const void *From,unsigned long Size)
 /* */
 bool FileFd::Seek(unsigned long To)
 {
-   if (lseek(iFd,To,SEEK_SET) != (signed)To)
+   int res;
+   if (gz)
+      res = gzseek(gz,To,SEEK_SET);
+   else
+      res = lseek(iFd,To,SEEK_SET);
+   if (res != (signed)To)
    {
       Flags |= Fail;
       return _error->Error("Unable to seek to %lu",To);
@@ -737,7 +756,12 @@ bool FileFd::Seek(unsigned long To)
 /* */
 bool FileFd::Skip(unsigned long Over)
 {
-   if (lseek(iFd,Over,SEEK_CUR) < 0)
+   int res;
+   if (gz)
+      res = gzseek(gz,Over,SEEK_CUR);
+   else
+      res = lseek(iFd,Over,SEEK_CUR);
+   if (res < 0)
    {
       Flags |= Fail;
       return _error->Error("Unable to seek ahead %lu",Over);
@@ -751,6 +775,11 @@ bool FileFd::Skip(unsigned long Over)
 /* */
 bool FileFd::Truncate(unsigned long To)
 {
+   if (gz)
+   {
+      Flags |= Fail;
+      return _error->Error("Truncating gzipped files is not implemented (%s)", FileName.c_str());
+   }
    if (ftruncate(iFd,To) != 0)
    {
       Flags |= Fail;
@@ -765,7 +794,11 @@ bool FileFd::Truncate(unsigned long To)
 /* */
 unsigned long FileFd::Tell()
 {
-   off_t Res = lseek(iFd,0,SEEK_CUR);
+   off_t Res;
+   if (gz)
+     Res = gztell(gz);
+   else
+     Res = lseek(iFd,0,SEEK_CUR);
    if (Res == (off_t)-1)
       _error->Errno("lseek","Failed to determine the current file position");
    return Res;
@@ -776,6 +809,7 @@ unsigned long FileFd::Tell()
 /* */
 unsigned long FileFd::Size()
 {
+   //TODO: For gz, do we need the actual file size here or the uncompressed length?
    struct stat Buf;
    if (fstat(iFd,&Buf) != 0)
       return _error->Errno("fstat","Unable to determine the file size");
@@ -789,9 +823,10 @@ bool FileFd::Close()
 {
    bool Res = true;
    if ((Flags & AutoClose) == AutoClose)
-      if (iFd >= 0 && close(iFd) != 0)
+      if ((gz != NULL && gzclose(gz) != 0) || (gz == NULL && iFd > 0 && close(iFd) != 0))
 	 Res &= _error->Errno("close",_("Problem closing the file"));
    iFd = -1;
+   gz = NULL;
    
    if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail &&
        FileName.empty() == false)
diff --git a/apt-pkg/contrib/fileutl.h b/apt-pkg/contrib/fileutl.h
index 85a94898c..9925bbed4 100644
--- a/apt-pkg/contrib/fileutl.h
+++ b/apt-pkg/contrib/fileutl.h
@@ -25,6 +25,8 @@
 #include <string>
 #include <vector>
 
+#include <zlib.h>
+
 using std::string;
 
 class FileFd
@@ -36,6 +38,7 @@ class FileFd
                     HitEof = (1<<3)};
    unsigned long Flags;
    string FileName;
+   gzFile gz;
    
    public:
    enum OpenMode {ReadOnly,WriteEmpty,WriteExists,WriteAny,WriteTemp};
@@ -69,12 +72,12 @@ class FileFd
    inline string &Name() {return FileName;};
    
    FileFd(string FileName,OpenMode Mode,unsigned long Perms = 0666) : iFd(-1), 
-            Flags(0) 
+            Flags(0), gz(NULL)
    {
       Open(FileName,Mode,Perms);
    };
-   FileFd(int Fd = -1) : iFd(Fd), Flags(AutoClose) {};
-   FileFd(int Fd,bool) : iFd(Fd), Flags(0) {};
+   FileFd(int Fd = -1) : iFd(Fd), Flags(AutoClose), gz(NULL) {};
+   FileFd(int Fd,bool) : iFd(Fd), Flags(0), gz(NULL) {};
    virtual ~FileFd();
 };