scons, style: Rename style.py to hgstyle.py

The Mercurial style checker extensions are currently stored in
style.py. This is not ideal since they won't work with other version
control systems. This changeset renames style.py to hgstyle.py and
adds upgrade code to scons that automatically updates the hooks in
hgrc.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Nathanael Premillieu <nathananel.premillieu@arm.com>
Reviewed-by: Steve Reinhardt <steve.reinhardt@amd.com>

--HG--
rename : util/style.py => util/hgstyle.py
extra : rebase_source : ee8107ef245901371b368b7c2046ecdd89e3ff4c

SConstruct

@@ -112,6 +112,7 @@ For more details, see:
 import itertools
 import os
 import re
+import shutil
 import subprocess
 import sys
 
@@ -266,15 +267,21 @@ against the gem5 style rules on hg commit and qrefresh commands.  This
 script will now install the hook in your .hg/hgrc file.
 Press enter to continue, or ctrl-c to abort: """
 
+mercurial_style_upgrade_message = """
+Your Mercurial style hooks are not up-to-date. This script will now
+try to automatically update them. A backup of your hgrc will be saved
+in .hg/hgrc.old.
+Press enter to continue, or ctrl-c to abort: """
+
 mercurial_style_hook = """
 # The following lines were automatically added by gem5/SConstruct
 # to provide the gem5 style-checking hooks
 [extensions]
-style = %s/util/style.py
+hgstyle = %s/util/hgstyle.py
 
 [hooks]
-pretxncommit.style = python:style.check_style
-pre-qrefresh.style = python:style.check_style
+pretxncommit.style = python:hgstyle.check_style
+pre-qrefresh.style = python:hgstyle.check_style
 # End of SConstruct additions
 
 """ % (main.root.abspath)
@@ -290,16 +297,52 @@ hook. It is important.
 # install a hook in, or there's no interactive terminal to prompt.
 if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
     style_hook = True
+    style_hooks = tuple()
+    hgrc = hgdir.File('hgrc')
+    hgrc_old = hgdir.File('hgrc.old')
     try:
         from mercurial import ui
         ui = ui.ui()
-        ui.readconfig(hgdir.File('hgrc').abspath)
-        style_hook = ui.config('hooks', 'pretxncommit.style', None) and \
-                     ui.config('hooks', 'pre-qrefresh.style', None)
+        ui.readconfig(hgrc.abspath)
+        style_hooks = (ui.config('hooks', 'pretxncommit.style', None),
+                       ui.config('hooks', 'pre-qrefresh.style', None))
+        style_hook = all(style_hooks)
+        style_extension = ui.config('extensions', 'style', None)
     except ImportError:
         print mercurial_lib_not_found
 
-    if not style_hook:
+    if "python:style.check_style" in style_hooks:
+        # Try to upgrade the style hooks
+        print mercurial_style_upgrade_message
+        # continue unless user does ctrl-c/ctrl-d etc.
+        try:
+            raw_input()
+        except:
+            print "Input exception, exiting scons.\n"
+            sys.exit(1)
+        shutil.copyfile(hgrc.abspath, hgrc_old.abspath)
+        re_style_hook = re.compile(r"^([^=#]+)\.style\s*=\s*([^#\s]+).*")
+        re_style_extension = re.compile("style\s*=\s*([^#\s]+).*")
+        with open(hgrc_old.abspath, 'r') as old, \
+             open(hgrc.abspath, 'w') as new:
+
+            for l in old:
+                m_hook = re_style_hook.match(l)
+                m_ext = re_style_extension.match(l)
+                if m_hook:
+                    hook, check = m_hook.groups()
+                    if check != "python:style.check_style":
+                        print "Warning: %s.style is using a non-default " \
+                            "checker: %s" % (hook, check)
+                    if hook not in ("pretxncommit", "pre-qrefresh"):
+                        print "Warning: Updating unknown style hook: %s" % hook
+
+                    l = "%s.style = python:hgstyle.check_style\n" % hook
+                elif m_ext and m_ext.group(1) == style_extension:
+                    l = "hgstyle = %s/util/hgstyle.py\n" % main.root.abspath
+
+                new.write(l)
+    elif not style_hook:
         print mercurial_style_message,
         # continue unless user does ctrl-c/ctrl-d etc.
         try:
@@ -310,9 +353,8 @@ if not GetOption('ignore_style') and hgdir.exists() and sys.stdin.isatty():
         hgrc_path = '%s/.hg/hgrc' % main.root.abspath
         print "Adding style hook to", hgrc_path, "\n"
         try:
-            hgrc = open(hgrc_path, 'a')
-            hgrc.write(mercurial_style_hook)
-            hgrc.close()
+            with open(hgrc_path, 'a') as f:
+                f.write(mercurial_style_hook)
         except:
             print "Error updating", hgrc_path
             sys.exit(1)