annotate: Convert all -| calls to use a helper open_pipe().

When we settle on a solution for ActiveState's forking issues, all
compatibility checks can be handled inside this one function.

Also, fixed an abuse of global variables in the process of cleaning this up.

Signed-off-by: Ryan Anderson <ryan@michonline.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/git-annotate.perl b/git-annotate.perl
index 91da6d5..ee8ff15 100755 (executable)
--- a/git-annotate.perl
+++ b/git-annotate.perl
@@ -98,15 +98,15 @@ while (my $bound = pop @stack) {
 push @revqueue, $head;
 init_claim( defined $starting_rev ? $starting_rev : 'dirty');
 unless (defined $starting_rev) {
-       open(DIFF,"-|","git","diff","-R", "HEAD", "--",$filename)
+       my $diff = open_pipe("git","diff","-R", "HEAD", "--",$filename)
                or die "Failed to call git diff to check for dirty state: $!";
 
-       _git_diff_parse(*DIFF, $head, "dirty", (
+       _git_diff_parse($diff, $head, "dirty", (
                                'author' => gitvar_name("GIT_AUTHOR_IDENT"),
                                'author_date' => sprintf("%s +0000",time()),
                                )
                        );
-       close(DIFF);
+       close($diff);
 }
 handle_rev();
 
@@ -172,20 +172,21 @@ sub handle_rev {
 sub git_rev_list {
        my ($rev, $file) = @_;
 
+       my $revlist;
        if ($rev_file) {
-               open(P, '<' . $rev_file);
+               open($revlist, '<' . $rev_file);
        } else {
-               open(P,"-|","git-rev-list","--parents","--remove-empty",$rev,"--",$file)
+               $revlist = open_pipe("git-rev-list","--parents","--remove-empty",$rev,"--",$file)
                        or die "Failed to exec git-rev-list: $!";
        }
 
        my @revs;
-       while(my $line = <P>) {
+       while(my $line = <$revlist>) {
                chomp $line;
                my ($rev, @parents) = split /\s+/, $line;
                push @revs, [ $rev, @parents ];
        }
-       close(P);
+       close($revlist);
 
        printf("0 revs found for rev %s (%s)\n", $rev, $file) if (@revs == 0);
        return @revs;
@@ -194,22 +195,22 @@ sub git_rev_list {
 sub find_parent_renames {
        my ($rev, $file) = @_;
 
-       open(P,"-|","git-diff-tree", "-M50", "-r","--name-status", "-z","$rev")
+       my $patch = open_pipe("git-diff-tree", "-M50", "-r","--name-status", "-z","$rev")
                or die "Failed to exec git-diff: $!";
 
        local $/ = "\0";
        my %bound;
-       my $junk = <P>;
-       while (my $change = <P>) {
+       my $junk = <$patch>;
+       while (my $change = <$patch>) {
                chomp $change;
-               my $filename = <P>;
+               my $filename = <$patch>;
                chomp $filename;
 
                if ($change =~ m/^[AMD]$/ ) {
                        next;
                } elsif ($change =~ m/^R/ ) {
                        my $oldfilename = $filename;
-                       $filename = <P>;
+                       $filename = <$patch>;
                        chomp $filename;
                        if ( $file eq $filename ) {
                                my $parent = git_find_parent($rev, $oldfilename);
@@ -218,7 +219,7 @@ sub find_parent_renames {
                        }
                }
        }
-       close(P);
+       close($patch);
 
        return \%bound;
 }
@@ -227,14 +228,14 @@ sub find_parent_renames {
 sub git_find_parent {
        my ($rev, $filename) = @_;
 
-       open(REVPARENT,"-|","git-rev-list","--remove-empty", "--parents","--max-count=1","$rev","--",$filename)
+       my $revparent = open_pipe("git-rev-list","--remove-empty", "--parents","--max-count=1","$rev","--",$filename)
                or die "Failed to open git-rev-list to find a single parent: $!";
 
-       my $parentline = <REVPARENT>;
+       my $parentline = <$revparent>;
        chomp $parentline;
        my ($revfound,$parent) = split m/\s+/, $parentline;
 
-       close(REVPARENT);
+       close($revparent);
 
        return $parent;
 }
@@ -245,13 +246,13 @@ sub git_find_parent {
 sub git_diff_parse {
        my ($parent, $rev, %revinfo) = @_;
 
-       open(DIFF,"-|","git-diff-tree","-M","-p",$rev,$parent,"--",
+       my $diff = open_pipe("git-diff-tree","-M","-p",$rev,$parent,"--",
                        $revs{$rev}{'filename'}, $revs{$parent}{'filename'})
                or die "Failed to call git-diff for annotation: $!";
 
-       _git_diff_parse(*DIFF, $parent, $rev, %revinfo);
+       _git_diff_parse($diff, $parent, $rev, %revinfo);
 
-       close(DIFF);
+       close($diff);
 }
 
 sub _git_diff_parse {
@@ -264,7 +265,7 @@ sub _git_diff_parse {
        my $gotheader = 0;
        my ($remstart);
        my ($hunk_start, $hunk_index);
-       while(<DIFF>) {
+       while(<$diff>) {
                chomp;
                if (m/^@@ -(\d+),(\d+) \+(\d+),(\d+)/) {
                        $remstart = $1;
@@ -335,15 +336,15 @@ sub git_cat_file {
 
        my $blob = git_ls_tree($rev, $filename);
 
-       open(C,"-|","git","cat-file", "blob", $blob)
+       my $catfile = open_pipe("git","cat-file", "blob", $blob)
                or die "Failed to git-cat-file blob $blob (rev $rev, file $filename): " . $!;
 
        my @lines;
-       while(<C>) {
+       while(<$catfile>) {
                chomp;
                push @lines, $_;
        }
-       close(C);
+       close($catfile);
 
        return @lines;
 }
@@ -351,15 +352,15 @@ sub git_cat_file {
 sub git_ls_tree {
        my ($rev, $filename) = @_;
 
-       open(T,"-|","git","ls-tree",$rev,$filename)
+       my $lstree = open_pipe("git","ls-tree",$rev,$filename)
                or die "Failed to call git ls-tree: $!";
 
        my ($mode, $type, $blob, $tfilename);
-       while(<T>) {
+       while(<$lstree>) {
                ($mode, $type, $blob, $tfilename) = split(/\s+/, $_, 4);
                last if ($tfilename eq $filename);
        }
-       close(T);
+       close($lstree);
 
        return $blob if $filename eq $filename;
        die "git-ls-tree failed to find blob for $filename";
@@ -379,11 +380,11 @@ sub claim_line {
 
 sub git_commit_info {
        my ($rev) = @_;
-       open(COMMIT, "-|","git-cat-file", "commit", $rev)
+       my $commit = open_pipe("git-cat-file", "commit", $rev)
                or die "Failed to call git-cat-file: $!";
 
        my %info;
-       while(<COMMIT>) {
+       while(<$commit>) {
                chomp;
                last if (length $_ == 0);
 
@@ -397,7 +398,7 @@ sub git_commit_info {
                        $info{'committer_date'} = $3;
                }
        }
-       close(COMMIT);
+       close($commit);
 
        return %info;
 }
@@ -430,3 +431,17 @@ sub gitvar_name {
     return join(' ', @field[0...(@field-4)]);
 }
 
+
+sub open_pipe {
+       my (@execlist) = @_;
+
+       my $pid = open my $kid, "-|";
+       defined $pid or die "Cannot fork: $!";
+
+       unless ($pid) {
+               exec @execlist;
+               die "Cannot exec @execlist: $!";
+       }
+
+       return $kid;
+}