[GN] Add support for generating Xcode projects.

tools/gn/xcode_writer.h

Index: tools/gn/xcode_writer.h
diff --git a/tools/gn/xcode_writer.h b/tools/gn/xcode_writer.h
new file mode 100644
index 0000000000000000000000000000000000000000..dd162c65f89695df89a468f2da70130989352b01
--- /dev/null
+++ b/tools/gn/xcode_writer.h
@@ -0,0 +1,97 @@
+// Copyright 2016 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_XCODE_WRITER_H_
+#define TOOLS_GN_XCODE_WRITER_H_
+
+#include <iosfwd>
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+
+class Builder;
+class BuildSettings;
+class Err;
+class SourceDir;
+class Target;
+
+using PBXAttributes = std::map<std::string, std::string>;
+class PBXProject;
+
+class XcodeWriter {
+ public:
+  enum TargetOsType {
+    WRITER_TARGET_OS_IOS,
+    WRITER_TARGET_OS_MACOS,
+  };
+
+  // Writes Xcode workspace and project files.
+  //
+  // |workspace_name| is the optional name of the workspace file name ("all"
+  // is used if not specified). |root_target_name| is the name of the main
+  // target corresponding to building "All" (for example "gn_all" in Chromium).
+  // |ninja_extra_args| are additional arguments to pass to ninja invocation
+  // (can be used to increase limit of concurrent processes when using goma).
+  // |dir_filters_string| is optional semicolon-separated list of label patterns
+  // used to limit the set of generated projects. Only matching targets will be
+  // included to the workspace. On failure will populate |err| and return false.
+  static bool RunAndWriteFiles(const std::string& workspace_name,
+                               const std::string& root_target_name,
+                               const std::string& ninja_extra_args,
+                               const std::string& dir_filters_string,
+                               const BuildSettings* build_settings,
+                               Builder* builder,
+                               Err* err);
+
+ private:
+  XcodeWriter(const std::string& name);
+  ~XcodeWriter();
+
+  // Filters the list of targets to only return the targets with artifacts
+  // usable from Xcode (mostly application bundles). On failure populate |err|
+  // and return false.
+  static bool FilterTargets(const BuildSettings* build_settings,
+                            const std::vector<const Target*>& all_targets,
+                            const std::string& dir_filters_string,
+                            std::vector<const Target*>* targets,
+                            Err* err);
+
+  // Generate the "products.xcodeproj" project that reference all products
+  // (i.e. targets that have a build artefact usable from Xcode, mostly
+  // application bundles).
+  void CreateProductsProject(const std::vector<const Target*>& targets,
+                             const PBXAttributes& attributes,
+                             const std::string& source_path,
+                             const std::string& config_name,
+                             const std::string& root_target,
+                             const std::string& ninja_extra_args,
+                             TargetOsType target_os);
+
+  // Generates the "sources.xcodeproj" project that reference all source
+  // files to allow Xcode to index them.
+  void CreateSourcesProject(const std::vector<const Target*>& targets,
+                            const SourceDir& root_build_dir,
+                            const PBXAttributes& attributes,
+                            const std::string& source_path,
+                            const std::string& config_name,
+                            TargetOsType target_os);
+
+  bool WriteFiles(const BuildSettings* build_settings, Err* err);
+  bool WriteProjectFile(const BuildSettings* build_settings,
+                        PBXProject* project,
+                        Err* err);
+
+  void WriteWorkspaceContent(std::ostream& out);
+  void WriteProjectContent(std::ostream& out, PBXProject* project);
+
+  std::string name_;
+  std::vector<std::unique_ptr<PBXProject>> projects_;
+
+  DISALLOW_COPY_AND_ASSIGN(XcodeWriter);
+};
+
+#endif  // TOOLS_GN_XCODE_WRITER_H_