add "hg gofmt" to run all modified files through gofmt.

add check before Upload, for now disabled by default,
that files do not change when run through gofmt.
enable by adding

	[codereview]
	force_gofmt = True

to .hgrc or .hg/hgrc.

add doc strings for a few more commands.
rename codereview-login to code-login
to make module doc visible.

R=r
CC=gri
http://go/go-review/1018056

lib/codereview/codereview.py

@@ -152,7 +152,9 @@ class CL(object):
 			s = "code review %s: %s" % (self.name, s)
 		return s
 
-	def Upload(self, ui, repo, send_mail=False):
+	def Upload(self, ui, repo, send_mail=False, gofmt=True):
+		if ui.configbool("codereview", "force_gofmt", False) and gofmt:
+			CheckGofmt(ui, repo, self.files)
 		os.chdir(repo.root)
 		form_fields = [
 			("content_upload", "1"),
@@ -434,6 +436,15 @@ def ChangedFiles(ui, repo, pats, opts):
 	l.sort()
 	return l
 
+# Return list of changed files in repository that match pats and still exist.
+def ChangedExistingFiles(ui, repo, pats, opts):
+	matcher = cmdutil.match(repo, pats, opts)
+	node1, node2 = cmdutil.revpair(repo, None)
+	modified, added, _ = repo.status(node1, node2, matcher)[:3]
+	l = modified + added
+	l.sort()
+	return l
+
 # Return list of files claimed by existing CLs
 def TakenFiles(ui, repo):
 	return Taken(ui, repo).keys()
@@ -543,6 +554,33 @@ def ReplacementForCmdutilMatch(repo, pats=[], opts={}, globbed=False, default='r
 	pats = Sub(pats, taken)	+ ['path:'+f for f in files]
 	return original_match(repo, pats=pats, opts=opts, globbed=globbed, default=default)
 
+def RelativePath(path, cwd):
+	n = len(cwd)
+	if path.startswith(cwd) and path[n] == '/':
+		return path[n+1:]
+	return path
+
+# Check that gofmt run on the list of files does not change them
+def CheckGofmt(ui, repo, files):
+	f = [f for f in files if f.endswith('.go')]
+	if not f:
+		return
+	cwd = os.getcwd()
+	files = [RelativePath(repo.root + '/' + f, cwd) for f in files]
+	try:
+		stdin, stdout, stderr = os.popen3(["gofmt", "-l"] + files)
+		stdin.close()
+	except:
+		raise util.Abort("gofmt: " + ExceptionDetail())
+	data = stdout.read()
+	errors = stderr.read()
+	if len(errors) > 0:
+		ui.warn("gofmt errors:\n" + errors.rstrip() + "\n")
+		return
+	if len(data) > 0:
+		raise util.Abort("gofmt needs to format these files (run hg gofmt):\n" + data)
+	return
+
 #######################################################################
 # Mercurial commands
 
@@ -643,7 +681,7 @@ def change(ui, repo, *pats, **opts):
 			ui.write("CL created: " + cl.url + "\n")
 	return
 
-def codereview_login(ui, repo, **opts):
+def code_login(ui, repo, **opts):
 	"""log in to code review server
 
 	Logs in to the code review server, saving a cookie in
@@ -710,7 +748,33 @@ def file(ui, repo, clname, pat, *pats, **opts):
 		d.Flush(ui, repo)
 	return
 
+def gofmt(ui, repo, *pats, **opts):
+	"""apply gofmt to modified files
+
+	Applies gofmt to the modified files in the repository that match
+	the given patterns.
+	"""
+	files = ChangedExistingFiles(ui, repo, pats, opts)
+	files = [f for f in files if f.endswith(".go")]
+	if not files:
+		return "no modified go files"
+	cwd = os.getcwd()
+	files = [RelativePath(repo.root + '/' + f, cwd) for f in files]
+	try:
+		if os.spawnvp(os.P_WAIT, "gofmt", ["gofmt", "-l", "-w"] + files) != 0:
+			raise util.Abort("gofmt did not exit cleanly")
+	except error.Abort, e:
+		raise
+	except:
+		raise util.Abort("gofmt: " + ExceptionDetail())
+	return
+
 def mail(ui, repo, *pats, **opts):
+	"""mail a change for review
+
+	Uploads a patch to the code review server and then sends mail
+	to the reviewer and CC list asking for a review.
+	"""
 	cl, err = CommandLineCL(ui, repo, pats, opts)
 	if err != "":
 		return err
@@ -723,9 +787,14 @@ def mail(ui, repo, *pats, **opts):
 	PostMessage(cl.name, pmsg, send_mail="checked", subject=cl.Subject())
 
 def nocommit(ui, repo, *pats, **opts):
+	"""(disabled when using this extension)"""
 	return "The codereview extension is enabled; do not use commit."
 
 def pending(ui, repo, *pats, **opts):
+	"""show pending changes
+
+	Lists pending changes followed by a list of unassigned but modified files.
+	"""
 	m = LoadAllCL(ui, repo, web=True)
 	names = m.keys()
 	names.sort()
@@ -902,6 +971,10 @@ def uisetup(ui):
 		commands.table["^commit|ci"] = (nocommit, [], "")
 
 def upload(ui, repo, name, **opts):
+	"""upload diffs to the code review server
+
+	Uploads the current modifications for a given change to the server.
+	"""
 	repo.ui.quiet = True
 	cl, err = LoadCL(ui, repo, name, web=True)
 	if err != "":
@@ -931,8 +1004,11 @@ cmdtable = {
 		],
 		"[-i] [-o] change# or FILE ..."
 	),
-	"codereview-login": (
-		codereview_login,
+	# Would prefer to call this codereview-login, but then
+	# hg help codereview prints the help for this command
+	# instead of the help for the extension.
+	"code-login": (
+		code_login,
 		[],
 		"",
 	),
@@ -948,6 +1024,11 @@ cmdtable = {
 		],
 		"[-d] change# FILE ..."
 	),
+	"^gofmt": (
+		gofmt,
+		[],
+		"FILE ..."
+	),
 	"^pending|p": (
 		pending,
 		[],