GN: Change gen command syntax, support relative dirs.

tools/gn/setup.h

 // Copyright (c) 2013 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.
 
 #ifndef TOOLS_GN_SETUP_H_
 #define TOOLS_GN_SETUP_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 60 matching lines @@
 
 // Helper class to setup the build settings and environment for the various
 // commands to run.
 class Setup : public CommonSetup {
  public:
   Setup();
   virtual ~Setup();
 
   // Configures the build for the current command line. On success returns
   // true. On failure, prints the error and returns false.
-  bool DoSetup();
+  //
+  // The parameter is the string the user specified for the build directory. We
+  // will try to interpret this as a SourceDir if possible, and will fail if is
+  // is malformed.
+  bool DoSetup(const std::string& build_dir);
 
   // Runs the load, returning true on success. On failure, prints the error
   // and returns false. This includes both RunPreMessageLoop() and
   // RunPostMessageLoop().
   bool Run();
 
   Scheduler& scheduler() { return scheduler_; }
 
   virtual Scheduler* GetScheduler() OVERRIDE;
 
  private:
   // Fills build arguments. Returns true on success.
   bool FillArguments(const CommandLine& cmdline);
 
   // Fills the root directory into the settings. Returns true on success.
   bool FillSourceDir(const CommandLine& cmdline);
 
+  // Fills the build directory given the value the user has specified.
+  // Must happen after FillSourceDir so we can resolve source-relative
+  // paths.
+  bool FillBuildDir(const std::string& build_dir);
+
   // Fills the python path portion of the command line. On failure, sets
   // it to just "python".
   void FillPythonPath();
 
   // Run config file.
   bool RunConfigFile();
 
   bool FillOtherConfig(const CommandLine& cmdline);
 
   Scheduler scheduler_;
@@ skipping 43 matching lines @@
   void RunPreMessageLoop();
   bool RunPostMessageLoop();
 
   virtual Scheduler* GetScheduler() OVERRIDE;
 
  private:
   Scheduler* scheduler_;
 };
 
 #endif  // TOOLS_GN_SETUP_H_