Simplify some mojo_shell code.

mojo/shell/desktop/main.cc

Index: mojo/shell/desktop/main.cc
diff --git a/mojo/shell/desktop/main.cc b/mojo/shell/desktop/main.cc
index 92149858e7e8e244f58570d050cbf9605336d1dc..ca89c5da94b727c86a6812fb70cb9072cf4e82ee 100644
--- a/mojo/shell/desktop/main.cc
+++ b/mojo/shell/desktop/main.cc
@@ -2,184 +2,23 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include <stdio.h>
-#include <string.h>
-
-#include <algorithm>
-#include <iostream>
-
 #include "base/at_exit.h"
-#include "base/base_switches.h"
-#include "base/bind.h"
 #include "base/command_line.h"
-#include "base/files/file_util.h"
-#include "base/message_loop/message_loop.h"
-#include "base/synchronization/waitable_event.h"
-#include "base/trace_event/trace_event.h"
 #include "mojo/shell/child_process.h"
-#include "mojo/shell/command_line_util.h"
-#include "mojo/shell/context.h"
+#include "mojo/shell/desktop/launcher_process.h"
 #include "mojo/shell/init.h"
 #include "mojo/shell/switches.h"
 
-namespace {
-
-void Usage() {
-  std::cerr << "Launch Mojo applications.\n";
-  std::cerr
-      << "Usage: mojo_shell"
-      << " [--" << switches::kArgsFor << "=<mojo-app>]"
-      << " [--" << switches::kContentHandlers << "=<handlers>]"
-      << " [--" << switches::kEnableExternalApplications << "]"
-      << " [--" << switches::kDisableCache << "]"
-      << " [--" << switches::kEnableMultiprocess << "]"
-      << " [--" << switches::kOrigin << "=<url-lib-path>]"
-      << " [--" << switches::kTraceStartup << "]"
-      << " [--" << switches::kURLMappings << "=from1=to1,from2=to2]"
-      << " [--" << switches::kPredictableAppFilenames << "]"
-      << " [--" << switches::kWaitForDebugger << "]"
-      << " <mojo-app> ...\n\n"
-      << "A <mojo-app> is a Mojo URL or a Mojo URL and arguments within "
-      << "quotes.\n"
-      << "Example: mojo_shell \"mojo:js_standalone test.js\".\n"
-      << "<url-lib-path> is searched for shared libraries named by mojo URLs.\n"
-      << "The value of <handlers> is a comma separated list like:\n"
-      << "text/html,mojo:html_viewer,"
-      << "application/javascript,mojo:js_content_handler\n";
-}
-
-// Whether we're currently tracing.
-bool g_tracing = false;
-
-// Number of tracing blocks written.
-uint32_t g_blocks = 0;
-
-// Trace file, if open.
-FILE* g_trace_file = nullptr;
-
-void WriteTraceDataCollected(
-    base::WaitableEvent* event,
-    const scoped_refptr<base::RefCountedString>& events_str,
-    bool has_more_events) {
-  if (g_blocks) {
-    fwrite(",", 1, 1, g_trace_file);
-  }
-
-  ++g_blocks;
-  fwrite(events_str->data().c_str(), 1, events_str->data().length(),
-         g_trace_file);
-  if (!has_more_events) {
-    static const char kEnd[] = "]}";
-    fwrite(kEnd, 1, strlen(kEnd), g_trace_file);
-    PCHECK(fclose(g_trace_file) == 0);
-    g_trace_file = nullptr;
-    event->Signal();
-  }
-}
-
-void EndTraceAndFlush(base::WaitableEvent* event) {
-  g_trace_file = fopen("mojo_shell.trace", "w+");
-  PCHECK(g_trace_file);
-  static const char kStart[] = "{\"traceEvents\":[";
-  fwrite(kStart, 1, strlen(kStart), g_trace_file);
-  base::trace_event::TraceLog::GetInstance()->SetDisabled();
-  base::trace_event::TraceLog::GetInstance()->Flush(
-      base::Bind(&WriteTraceDataCollected, base::Unretained(event)));
-}
-
-void StopTracingAndFlushToDisk() {
-  g_tracing = false;
-  base::trace_event::TraceLog::GetInstance()->SetDisabled();
-  base::WaitableEvent flush_complete_event(false, false);
-  // TraceLog::Flush requires a message loop but we've already shut ours down.
-  // Spin up a new thread to flush things out.
-  base::Thread flush_thread("mojo_shell_trace_event_flush");
-  flush_thread.Start();
-  flush_thread.message_loop()->PostTask(
-      FROM_HERE,
-      base::Bind(EndTraceAndFlush, base::Unretained(&flush_complete_event)));
-  flush_complete_event.Wait();
-}
-
-}  // namespace
-
 int main(int argc, char** argv) {
   base::AtExitManager at_exit;
   base::CommandLine::Init(argc, argv);
 
   mojo::shell::InitializeLogging();
 
-  // TODO(vtl): Unify parent and child process cases to the extent possible.
-  if (scoped_ptr<mojo::shell::ChildProcess> child_process =
-          mojo::shell::ChildProcess::Create(
-              *base::CommandLine::ForCurrentProcess())) {
-    child_process->Main();
-  } else {
-    // Only check the command line for the main process.
-    const base::CommandLine& command_line =
-        *base::CommandLine::ForCurrentProcess();
-
-    const std::set<std::string> all_switches = switches::GetAllSwitches();
-    const base::CommandLine::SwitchMap switches = command_line.GetSwitches();
-    bool found_unknown_switch = false;
-    for (const auto& s : switches) {
-      if (all_switches.find(s.first) == all_switches.end()) {
-        std::cerr << "unknown switch: " << s.first << std::endl;
-        found_unknown_switch = true;
-      }
-    }
-
-    if (found_unknown_switch ||
-        (!command_line.HasSwitch(switches::kEnableExternalApplications) &&
-         (command_line.HasSwitch(switches::kHelp) ||
-          command_line.GetArgs().empty()))) {
-      Usage();
-      return 0;
-    }
-
-    if (command_line.HasSwitch(switches::kTraceStartup)) {
-      g_tracing = true;
-      base::trace_event::CategoryFilter category_filter(
-          command_line.GetSwitchValueASCII(switches::kTraceStartup));
-      base::trace_event::TraceLog::GetInstance()->SetEnabled(
-          category_filter, base::trace_event::TraceLog::RECORDING_MODE,
-          base::trace_event::TraceOptions(
-              base::trace_event::RECORD_UNTIL_FULL));
-    }
-
-    // We want the shell::Context to outlive the MessageLoop so that pipes are
-    // all gracefully closed / error-out before we try to shut the Context down.
-    mojo::shell::Context shell_context;
-    {
-      base::MessageLoop message_loop;
-      if (!shell_context.Init()) {
-        Usage();
-        return 0;
-      }
-      if (g_tracing) {
-        message_loop.PostDelayedTask(FROM_HERE,
-                                     base::Bind(StopTracingAndFlushToDisk),
-                                     base::TimeDelta::FromSeconds(5));
-      }
-
-      // The mojo_shell --args-for command-line switch is handled specially
-      // because it can appear more than once. The base::CommandLine class
-      // collapses multiple occurrences of the same switch.
-      for (int i = 1; i < argc; i++) {
-        ApplyApplicationArgs(&shell_context, argv[i]);
-      }
-
-      message_loop.PostTask(
-          FROM_HERE,
-          base::Bind(&mojo::shell::RunCommandLineApps, &shell_context));
-      message_loop.Run();
-
-      // Must be called before |message_loop| is destroyed.
-      shell_context.Shutdown();
-    }
-  }
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+  if (command_line.HasSwitch(switches::kChildProcess))
+    return mojo::shell::ChildProcessMain();
 
-  if (g_tracing)
-    StopTracingAndFlushToDisk();
-  return 0;
+  return mojo::shell::LauncherProcessMain(argc, argv);
 }