Check in a little toy that graphs history of words in the source.

Useful for tracking progress on projects like wstring removal.

Review URL: http://codereview.chromium.org/3017058

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@55107 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 52 insertions, 2 deletions

diff --git a/tools/git/README b/tools/git/README
index 18d6da7..7f8e363 100644
--- a/tools/git/README
+++ b/tools/git/README
@@ -1,8 +1,16 @@
-This directory contains some helpful Git hooks.
+This directory contains some helpful Git tools.
 
-Currently, they warn you about DEPS modifications so you will remember
+post-checkout and post-merge
+============================
+These hooks warn you about DEPS modifications so you will remember
 to run "gclient sync".
 
 To install these Git hooks, create symlinks like so:
   ln -s $(pwd)/post-checkout $(git rev-parse --git-dir)/hooks
   ln -s $(pwd)/post-merge    $(git rev-parse --git-dir)/hooks
+
+
+git-graph
+=========
+Create a graph of the recent history of occurences of a grep
+expression in the project.
diff --git a/tools/git/graph.sh b/tools/git/graph.sh
new file mode 100755
index 0000000..4d2bcb2
--- /dev/null
+++ b/tools/git/graph.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+about="Given a grep expression, creates a graph of occurrences of that
+expression in the recent history of the tree.
+
+Prerequisites: git and GNU R (apt-get install r-base).
+"
+
+set -e
+
+target="$1"
+
+if [ -z $target ]; then
+    echo "usage: $0 <grep-compatible expression>"
+    echo
+    echo "$about"
+    exit 1
+fi
+
+datafile=$(mktemp)
+trap "rm -f $datafile" EXIT
+
+echo 'ago count' > $datafile
+for ago in {90..0}; do
+    commit=$(git rev-list -1 --until="$ago days ago" origin/trunk)
+    git checkout -q -f $commit
+    count=$(git grep -E "$target" -- '*.cc' '*.h' '*.m' '*.mm' | wc -l)
+    echo "-$ago $count" >> $datafile
+    echo -n '.'
+done
+
+R CMD BATCH <(cat <<EOF
+data = read.delim("$datafile", sep=' ')
+png(width=600, height=300)
+plot(count ~ ago, type="l", main="$target", xlab='days ago', data=data)
+EOF
+) /dev/null
+
+echo done.  # Primarily to add a newline after all the dots.