Joshua Clayton <stillcompiling@xxxxxxxxx> writes:
> Read and write each 1024 byte buffer, rather than trying to buffer
> the entire content of the file.
> Previous code would crash on all files > 2 Gib, when the offset variable
> became negative (perhaps below the level of perl), resulting in a crash.
> On a 32 bit system, or a system with low memory it might crash before
> reaching 2 GiB due to memory exhaustion.
>
> Signed-off-by: Joshua Clayton <stillcompiling@xxxxxxxxx>
> Reviewed-by: Jeff King <peff@xxxxxxxx>
> ---
Thanks.
>> Subject: Re: [PATCH] Fix in Git.pm cat_blob crashes on large files (resubmit with reviewed-by)
Please drop the () part. A rule of thumb is to make "git show"
output understandable by people who read it 6 months from now. They
do not care if the commit is a re-submission.
It seems that this issue was with us since the very beginning of
this sub since it was introduced at 7182530d8cad (Git.pm: Add
hash_and_insert_object and cat_blob, 2008-05-23).
> perl/Git.pm | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/perl/Git.pm b/perl/Git.pm
> index 931047c..cc91288 100644
> --- a/perl/Git.pm
> +++ b/perl/Git.pm
> @@ -949,13 +949,16 @@ sub cat_blob {
> last unless $bytesLeft;
>
> my $bytesToRead = $bytesLeft < 1024 ? $bytesLeft : 1024;
> - my $read = read($in, $blob, $bytesToRead, $bytesRead);
> + my $read = read($in, $blob, $bytesToRead);
> unless (defined($read)) {
> $self->_close_cat_blob();
> throw Error::Simple("in pipe went bad");
> }
> -
> $bytesRead += $read;
> + unless (print $fh $blob) {
> + $self->_close_cat_blob();
> + throw Error::Simple("couldn't write to passed
> in filehandle");
> + }
Corrupt patch, line-wrapped by your MUA.
I wonder if we still need $bytesRead variable. You have $size that
is the size of the whole blob, so
my $bytesLeft = $size;
while (1) {
my $bytesToRead = $bytesLeft < 1024 ? $bytesLeft : 1024;
my $bytesRead = read($in, $blob, $bytesToRead);
... check errors and use the $blob ...
$bytesLeft -= $bytesRead;
}
may be simpler and easier to read, no?
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