Port "Eclipse CDT settings" file generation from GYP to GN

tools/gn/command_gen.cc

 // 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.
 
 #include "base/atomicops.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/timer/elapsed_timer.h"
 #include "tools/gn/build_settings.h"
 #include "tools/gn/commands.h"
+#include "tools/gn/eclipse_writer.h"
 #include "tools/gn/ninja_target_writer.h"
 #include "tools/gn/ninja_writer.h"
 #include "tools/gn/runtime_deps.h"
 #include "tools/gn/scheduler.h"
 #include "tools/gn/setup.h"
 #include "tools/gn/standard_out.h"
 #include "tools/gn/switches.h"
 #include "tools/gn/target.h"
 #include "tools/gn/visual_studio_writer.h"
 
 namespace commands {
 
 namespace {
 
 const char kSwitchCheck[] = "check";
 const char kSwitchIde[] = "ide";
+const char kSwitchIdeValueEclipse[] = "eclipse";
 const char kSwitchIdeValueVs[] = "vs";
 
 // Called on worker thread to write the ninja file.
 void BackgroundDoWrite(const Target* target) {
   NinjaTargetWriter::RunAndWriteFile(target);
   g_scheduler->DecrementWorkCount();
 }
 
 // Called on the main thread.
 void ItemResolvedCallback(base::subtle::Atomic32* write_counter,
@@ skipping 105 matching lines @@
     OutputString(base::StringPrintf("\n%d generated input errors found.\n",
                                     errors_found), DECORATION_YELLOW);
   }
   return false;
 }
 
 bool RunIdeWriter(const std::string& ide,
                   const BuildSettings* build_settings,
                   Builder* builder,
                   Err* err) {
-  if (ide == kSwitchIdeValueVs) {
-    base::ElapsedTimer timer;
+  base::ElapsedTimer timer;
+  if (ide == kSwitchIdeValueEclipse) {
+    bool res = EclipseWriter::RunAndWriteFile(build_settings, builder, err);
+    if (res) {
+      OutputString("Generating Eclipse settings took " +
+                   base::Int64ToString(timer.Elapsed().InMilliseconds()) +
+                   "ms\n");
+    }
+    return res;
+  } else if (ide == kSwitchIdeValueVs) {
     bool res =
         VisualStudioWriter::RunAndWriteFiles(build_settings, builder, err);
     if (res &&
         !base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kQuiet)) {
       OutputString("Generating Visual Studio projects took " +
                    base::Int64ToString(timer.Elapsed().InMilliseconds()) +
                    "ms\n");
     }
     return res;
   }
@@ skipping 16 matching lines @@
     "  output directory.\n"
     "\n"
     "  The output directory can be a source-repo-absolute path name such as:\n"
     "      //out/foo\n"
     "  Or it can be a directory relative to the current directory such as:\n"
     "      out/foo\n"
     "\n"
     "  --ide=<ide_name>\n"
     "    Also generate files for an IDE. Currently supported values:\n"
     "      'vs' - Visual Studio project/solution files.\n"
+    "      'eclipse' - Eclipse CDT settings file.\n"
     "\n"
-    "  See \"gn help switches\" for the common command-line switches.\n";
+    "  See \"gn help switches\" for the common command-line switches.\n"
+    "\n"
+    "Eclipse IDE Support\n"
+    "\n"
+    "  GN DOES NOT generate Eclipse CDT projects. Instead, it generates a\n"
+    "  settings file which can be imported into an Eclipse CDT project. The\n"
+    "  XML file contains a list of include paths and defines. Because GN does\n"
+    "  not generate a full .cproject definition, it is not possible to\n"
+    "  properly define includes/defines for each file individually.\n"
+    "  Instead, one set of includes/defines is generated for the entire\n"
+    "  project. This works fairly well but may still result in a few indexer\n"
+    "  issues here and there.\n";
 
 int RunGen(const std::vector<std::string>& args) {
   base::ElapsedTimer timer;
 
   if (args.size() != 1) {
     Err(Location(), "Need exactly one build directory to generate.",
         "I expected something more like \"gn gen out/foo\"\n"
         "You can also see \"gn help gen\".").PrintToStdout();
     return 1;
   }
@@ skipping 55 matching lines @@
             setup->scheduler().input_file_manager()->GetInputFileCount()) +
         " files in " +
         base::Int64ToString(elapsed_time.InMilliseconds()) + "ms\n";
     OutputString(stats);
   }
 
   return 0;
 }
 
 }  // namespace commands