checkpatch: cache last camelcase hash as .checkpatch-camelcase.<commit>

Add a file to cache the CamelCase variables found by <commit> to reduce
the time it takes to scan the include/ directory.

Filename is '.checkpatch-camelcase.<commit>' and it is created only only
if a .git directory exists.

<commit> is determined by the last non-merge commit id in the
include/ path.

Reduces checkpatch run time by ~12 cpu seconds on my little netbook.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 0d94853..6afcd12 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -399,7 +399,23 @@ sub seed_camelcase_includes {
        return if ($camelcase_seeded);
 
        my $files;
+       my $camelcase_git_file = "";
+
        if (-d ".git") {
+               my $git_last_include_commit = `git log --no-merges --pretty=format:"%h%n" -1 -- include`;
+               chomp $git_last_include_commit;
+               $camelcase_git_file = ".checkpatch-camelcase.$git_last_include_commit";
+               if (-f $camelcase_git_file) {
+                       open(my $camelcase_file, '<', "$camelcase_git_file")
+                           or warn "$P: Can't read '$camelcase_git_file' $!\n";
+                       while (<$camelcase_file>) {
+                               chomp;
+                               $camelcase{$_} = 1;
+                       }
+                       close($camelcase_file);
+
+                       return;
+               }
                $files = `git ls-files include`;
        } else {
                $files = `find $root/include -name "*.h"`;
@@ -409,6 +425,16 @@ sub seed_camelcase_includes {
                seed_camelcase_file($file);
        }
        $camelcase_seeded = 1;
+
+       if ($camelcase_git_file ne "") {
+               unlink glob ".checkpatch-camelcase.*";
+               open(my $camelcase_file, '>', "$camelcase_git_file")
+                   or warn "$P: Can't write '$camelcase_git_file' $!\n";
+               foreach (sort { lc($a) cmp lc($b) } keys(%camelcase)) {
+                       print $camelcase_file ("$_\n");
+               }
+               close($camelcase_file);
+       }
 }
 
 $chk_signoff = 0 if ($file);