lint-hunks: better support for working tree

When run with no arguments, report warnings in the diff between the
working tree and HEAD. With arguments, report warnings in the diff
between the named commit and its parents.

Change-Id: Ie10dcdecb303edf8af51bad645cc11206a1fc26b

1 files changed, 15 insertions, 6 deletions

diff --git a/tools/lint-hunks.py b/tools/lint-hunks.py
index 312fab138..b15a69143 100755
--- a/tools/lint-hunks.py
+++ b/tools/lint-hunks.py
@@ -22,7 +22,7 @@ LONG_OPTIONS = ["help"]
 
 TOPLEVEL_CMD = ["git", "rev-parse", "--show-toplevel"]
 DIFF_CMD = ["git", "diff"]
-DIFF_INDEX_CMD = ["git", "diff-index", "-u", "--cached", "HEAD", "--"]
+DIFF_INDEX_CMD = ["git", "diff-index", "-u", "HEAD", "--"]
 SHOW_CMD = ["git", "show"]
 CPPLINT_FILTERS = ["-readability/casting", "-runtime/int"]
 
@@ -106,11 +106,20 @@ def main(argv=None):
         for filename, affected_lines in file_affected_line_map.iteritems():
             if filename.split(".")[-1] not in ("c", "h", "cc"):
                 continue
-            show_cmd = SHOW_CMD + [":" + filename]
-            show = Subprocess(show_cmd, stdout=subprocess.PIPE)
-            lint = Subprocess(cpplint_cmd, expected_returncode=(0, 1),
-                              stdin=show.stdout, stderr=subprocess.PIPE)
-            lint_out = lint.communicate()[1]
+
+            if args:
+                # File contents come from git
+                show_cmd = SHOW_CMD + [args[0] + ":" + filename]
+                show = Subprocess(show_cmd, stdout=subprocess.PIPE)
+                lint = Subprocess(cpplint_cmd, expected_returncode=(0, 1),
+                                  stdin=show.stdout, stderr=subprocess.PIPE)
+                lint_out = lint.communicate()[1]
+            else:
+                # File contents come from the working tree
+                lint = Subprocess(cpplint_cmd, expected_returncode=(0, 1),
+                                  stdin=subprocess.PIPE, stderr=subprocess.PIPE)
+                stdin = open(os.path.join(tl, filename)).read()
+                lint_out = lint.communicate(stdin)[1]
 
             for line in lint_out.split("\n"):
                 fields = line.split(":")