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authorDavid Kalnischkies <kalnischkies@gmail.com>2011-12-17 17:31:47 +0100
committerDavid Kalnischkies <kalnischkies@gmail.com>2011-12-17 17:31:47 +0100
commit1abbc47c045770476f5f9a57c58989d13290d51b (patch)
tree536a79082b979ef540456876e71d1bbd6c27a102 /apt-pkg/contrib
parent6fd947bd48449652edf783cfb1362391e63f9be1 (diff)
keep track of where we are in a filedescriptor so we can use it as Tell()
information if we are working on a pipe which can't seek
Diffstat (limited to 'apt-pkg/contrib')
-rw-r--r--apt-pkg/contrib/fileutl.cc39
1 files changed, 30 insertions, 9 deletions
diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index a98c2cb85..bb836e93b 100644
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -75,7 +75,9 @@ class FileFdPrivate {
bool pipe;
APT::Configuration::Compressor compressor;
unsigned int openmode;
- FileFdPrivate() : gz(NULL), compressed_fd(-1), compressor_pid(-1), pipe(false) {};
+ unsigned long long seekpos;
+ FileFdPrivate() : gz(NULL), compressed_fd(-1), compressor_pid(-1), pipe(false),
+ openmode(0), seekpos(0) {};
};
// RunScripts - Run a set of scripts from a configuration subtree /*{{{*/
@@ -1065,6 +1067,7 @@ bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual)
To = (char *)To + Res;
Size -= Res;
+ d->seekpos += Res;
if (Actual != 0)
*Actual += Res;
}
@@ -1134,6 +1137,7 @@ bool FileFd::Write(const void *From,unsigned long long Size)
From = (char *)From + Res;
Size -= Res;
+ d->seekpos += Res;
}
while (Res > 0 && Size > 0);
@@ -1151,6 +1155,13 @@ bool FileFd::Seek(unsigned long long To)
{
if (d->pipe == true)
{
+ // Our poor man seeking in pipes is costly, so try to avoid it
+ unsigned long long seekpos = Tell();
+ if (seekpos == To)
+ return true;
+ else if (seekpos < To)
+ return Skip(To - seekpos);
+
if ((d->openmode & ReadOnly) != ReadOnly)
return _error->Error("Reopen is only implemented for read-only files!");
close(iFd);
@@ -1173,6 +1184,8 @@ bool FileFd::Seek(unsigned long long To)
if (To != 0)
return Skip(To);
+
+ d->seekpos = To;
return true;
}
int res;
@@ -1187,7 +1200,8 @@ bool FileFd::Seek(unsigned long long To)
Flags |= Fail;
return _error->Error("Unable to seek to %llu", To);
}
-
+
+ d->seekpos = To;
return true;
}
/*}}}*/
@@ -1208,7 +1222,8 @@ bool FileFd::Skip(unsigned long long Over)
Flags |= Fail;
return _error->Error("Unable to seek ahead %llu",Over);
}
-
+ d->seekpos = res;
+
return true;
}
/*}}}*/
@@ -1236,6 +1251,13 @@ bool FileFd::Truncate(unsigned long long To)
/* */
unsigned long long FileFd::Tell()
{
+ // In theory, we could just return seekpos here always instead of
+ // seeking around, but not all users of FileFd use always Seek() and co
+ // so d->seekpos isn't always true and we can just use it as a hint if
+ // we have nothing else, but not always as an authority…
+ if (d->pipe == true)
+ return d->seekpos;
+
off_t Res;
#if APT_USE_ZLIB
if (d->gz != NULL)
@@ -1245,6 +1267,7 @@ unsigned long long FileFd::Tell()
Res = lseek(iFd,0,SEEK_CUR);
if (Res == (off_t)-1)
_error->Errno("lseek","Failed to determine the current file position");
+ d->seekpos = Res;
return Res;
}
/*}}}*/
@@ -1281,15 +1304,14 @@ unsigned long long FileFd::Size()
// so we 'read' the content and 'seek' back - see there
if (d->pipe == true)
{
- // FIXME: If we have read first and then FileSize() the report is wrong
- size = 0;
+ unsigned long long const oldSeek = Tell();
char ignore[1000];
unsigned long long read = 0;
do {
Read(ignore, sizeof(ignore), &read);
- size += read;
} while(read != 0);
- Seek(0);
+ size = Tell();
+ Seek(oldSeek);
}
#if APT_USE_ZLIB
// only check gzsize if we are actually a gzip file, just checking for
@@ -1301,7 +1323,6 @@ unsigned long long FileFd::Size()
* this ourselves; the original (uncompressed) file size is the last 32
* bits of the file */
// FIXME: Size for gz-files is limited by 32bit… no largefile support
- off_t orig_pos = lseek(iFd, 0, SEEK_CUR);
if (lseek(iFd, -4, SEEK_END) < 0)
return _error->Errno("lseek","Unable to seek to end of gzipped file");
size = 0L;
@@ -1315,7 +1336,7 @@ unsigned long long FileFd::Size()
size = tmp_size;
#endif
- if (lseek(iFd, orig_pos, SEEK_SET) < 0)
+ if (lseek(iFd, d->seekpos, SEEK_SET) < 0)
return _error->Errno("lseek","Unable to seek in gzipped file");
return size;
}