Update mojo shell so that --args-for can be used on android

shell/command_line_util.cc

+// Copyright 2014 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.
+
+#include "shell/command_line_util.h"
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/strings/string_split.h"
+#include "base/strings/utf_string_conversions.h"
+#include "shell/context.h"
+#include "shell/switches.h"
+
+namespace mojo {
+namespace shell {
+
+namespace {
+bool IsEmpty(const std::string& s) {
+  return s.empty();
+}
+
+// The value of app_url_and_args is "<mojo_app_url> [<args>...]", where args
+// is a list of "configuration" arguments separated by spaces. If one or more
+// arguments are specified they will be available when the Mojo application
+// is initialized. See ApplicationImpl::args().
+GURL GetAppURLAndSetArgs(const std::string& app_url_and_args,
+                         Context* context) {
+  // SplitString() returns empty strings for extra delimeter characters (' ').
+  std::vector<std::string> argv;
+  base::SplitString(app_url_and_args, ' ', &argv);
+  argv.erase(std::remove_if(argv.begin(), argv.end(), IsEmpty), argv.end());
+
+  if (argv.empty())
+    return GURL::EmptyGURL();

[sky, 2014/12/17 16:44:05]

GURL() is fine here. GURL::EmptyGURL() is only necessary if you were returning a
const GURL&.

[qsr, 2014/12/18 14:21:35]

 Done.

 I agree that it is less useful in the current case, but why not to use it
still? At worst it doesn't change anything (if the compiler optimize the
creation/copy into a single creation), at best, it prevents an object creation)

 (Also note that all this code was just copied away)

[sky, 2014/12/18 17:01:15]

Mainly because it isn't overly obvious what that function is doing (I had to
look). With GURL() it's pretty clear what is happening.
Actually, I'm not entirely sure which is faster. ::EmptyGURL() does have some
potential overhead associated with it.

+  GURL app_url(argv[0]);
+  if (!app_url.is_valid()) {
+    LOG(ERROR) << "Error: invalid URL: " << argv[0];
+    return app_url;
+  }
+  if (argv.size() > 1)
+    context->application_manager()->SetArgsForURL(argv, app_url);

[sky, 2014/12/17 16:44:05]

Is it expected that you supply the url in argv? I would have though you needed
to do argv.erase(argv.begin()).

[qsr, 2014/12/18 14:21:35]

 Hum... This code has just moved here. Now, I guess we let the url there so that
the first argument is the name of the application, the same way argv[0] is the
name of the application.

+  return app_url;
+}
+
+bool IsArgsFor(const std::string& arg, std::string* value) {

[sky, 2014/12/17 16:44:05]

Add a description here. Especially what |value| is set to.

I would be inclined to name this GetArgsForValue().

[qsr, 2014/12/18 14:21:36]

 Added a description. Renamed this ParseArgsFor

+  const std::string kArgsForSwitches[] = {
+      "-" + std::string(switches::kArgsFor),
+      "--" + std::string(switches::kArgsFor),
+  };
+  for (size_t i = 0; i < arraysize(kArgsForSwitches); i++) {
+    std::string argsfor_switch(kArgsForSwitches[i]);

[sky, 2014/12/17 16:44:05]

const std::string&

[qsr, 2014/12/18 14:21:35]

Done.

+    if (arg.compare(0, argsfor_switch.size(), argsfor_switch) == 0) {
+      *value = arg.substr(argsfor_switch.size() + 1, std::string::npos);
+      return true;
+    }
+  }
+  return false;
+}
+
+}  // namespace
+
+void ApplyApplicationArgs(Context* context, const std::string args) {
+  std::string args_for_value;
+  if (IsArgsFor(args, &args_for_value))
+    GetAppURLAndSetArgs(args_for_value, context);
+}
+
+void RunCommandLineApps(Context* context) {
+  const auto& command_line = *base::CommandLine::ForCurrentProcess();
+  for (const auto& arg : command_line.GetArgs()) {
+    std::string arg2;
+#if defined(OS_WIN)
+    arg2 = base::UTF16ToUTF8(arg);
+#else
+    arg2 = arg;
+#endif
+    GURL url = GetAppURLAndSetArgs(arg2, context);
+    if (!url.is_valid())
+      return;
+    context->Run(url);
+  }
+}
+
+}  // namespace shell
+}  // namespace mojo