Support more configurability in GN toolchains

tools/gn/ninja_helper.cc

Index: tools/gn/ninja_helper.cc
diff --git a/tools/gn/ninja_helper.cc b/tools/gn/ninja_helper.cc
deleted file mode 100644
index 956e74c276b3d5db021e242de2b795d3c558b577..0000000000000000000000000000000000000000
--- a/tools/gn/ninja_helper.cc
+++ /dev/null
@@ -1,240 +0,0 @@
-// 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 "tools/gn/ninja_helper.h"
-
-#include "base/logging.h"
-#include "base/strings/string_util.h"
-#include "tools/gn/filesystem_utils.h"
-#include "tools/gn/string_utils.h"
-#include "tools/gn/target.h"
-
-namespace {
-
-const char kObjectDirNoSlash[] = "obj";
-
-}  // namespace
-
-NinjaHelper::NinjaHelper(const BuildSettings* build_settings)
-    : build_settings_(build_settings) {
-  build_to_src_no_last_slash_ = build_settings->build_to_source_dir_string();
-  if (!build_to_src_no_last_slash_.empty() &&
-      build_to_src_no_last_slash_[build_to_src_no_last_slash_.size() - 1] ==
-          '/')
-    build_to_src_no_last_slash_.resize(build_to_src_no_last_slash_.size() - 1);
-
-  build_to_src_system_no_last_slash_ = build_to_src_no_last_slash_;
-}
-
-NinjaHelper::~NinjaHelper() {
-}
-
-std::string NinjaHelper::GetTopleveOutputDir() const {
-  return kObjectDirNoSlash;
-}
-
-OutputFile NinjaHelper::GetTargetOutputDir(const Target* target) const {
-  OutputFile ret(target->settings()->toolchain_output_subdir());
-  ret.value().append(kObjectDirNoSlash);
-  AppendStringPiece(&ret.value(),
-                    target->label().dir().SourceAbsoluteWithOneSlash());
-  return ret;
-}
-
-OutputFile NinjaHelper::GetNinjaFileForTarget(const Target* target) const {
-  OutputFile ret = GetTargetOutputDir(target);
-  ret.value().append(target->label().name());
-  ret.value().append(".ninja");
-  return ret;
-}
-
-OutputFile NinjaHelper::GetNinjaFileForToolchain(
-    const Settings* settings) const {
-  OutputFile ret;
-  ret.value().append(settings->toolchain_output_subdir().value());
-  ret.value().append("toolchain.ninja");
-  return ret;
-}
-
-// In Python, GypPathToUniqueOutput does the qualification. The only case where
-// the Python version doesn't qualify the name is for target outputs, which we
-// handle in a separate function.
-OutputFile NinjaHelper::GetOutputFileForSource(
-    const Target* target,
-    const SourceFile& source,
-    SourceFileType type) const {
-  // Extract the filename and remove the extension (keep the dot).
-  base::StringPiece filename = FindFilename(&source.value());
-  std::string name(filename.data(), filename.size());
-  size_t extension_offset = FindExtensionOffset(name);
-  CHECK(extension_offset != std::string::npos);
-  name.resize(extension_offset);
-
-  // Append the new extension.
-  switch (type) {
-    case SOURCE_ASM:
-    case SOURCE_C:
-    case SOURCE_CC:
-    case SOURCE_M:
-    case SOURCE_MM:
-    case SOURCE_S:
-      name.append(target->settings()->IsWin() ? "obj" : "o");
-      break;
-
-    case SOURCE_RC:
-      name.append("res");
-      break;
-
-    // Pass .o/.obj files through unchanged.
-    case SOURCE_O: {
-      // System-absolute file names get preserved (they don't need to be
-      // rebased relative to the build dir).
-      if (source.is_system_absolute())
-        return OutputFile(source.value());
-
-      // Files that are already inside the build dir should not be made
-      // relative to the source tree. Doing so will insert an unnecessary
-      // "../.." into the path which won't match the corresponding target
-      // name in ninja.
-      CHECK(build_settings_->build_dir().is_source_absolute());
-      CHECK(source.is_source_absolute());
-      if (StartsWithASCII(source.value(),
-                          build_settings_->build_dir().value(),
-                          true)) {
-        return OutputFile(
-            source.value().substr(
-                build_settings_->build_dir().value().size()));
-      }
-
-      // Construct the relative location of the file from the build dir.
-      OutputFile ret(build_to_src_no_last_slash());
-      source.SourceAbsoluteWithOneSlash().AppendToString(&ret.value());
-      return ret;
-    }
-
-    case SOURCE_H:
-    case SOURCE_UNKNOWN:
-      NOTREACHED();
-      return OutputFile();
-  }
-
-  // Use the scheme <path>/<target>.<name>.<extension> so that all output
-  // names are unique to different targets.
-
-  // This will look like "obj" or "toolchain_name/obj".
-  OutputFile ret(target->settings()->toolchain_output_subdir());
-  ret.value().append(kObjectDirNoSlash);
-
-  // Find the directory, assume it starts with two slashes, and trim to one.
-  base::StringPiece dir = FindDir(&source.value());
-  CHECK(dir.size() >= 2 && dir[0] == '/' && dir[1] == '/')
-      << "Source file isn't in the source repo: " << dir;
-  AppendStringPiece(&ret.value(), dir.substr(1));
-
-  ret.value().append(target->label().name());
-  ret.value().append(".");
-  ret.value().append(name);
-  return ret;
-}
-
-OutputFile NinjaHelper::GetTargetOutputFile(const Target* target) const {
-  OutputFile ret;
-
-  // Use the output name if given, fall back to target name if not.
-  const std::string& name = target->output_name().empty() ?
-      target->label().name() : target->output_name();
-
-  // This is prepended to the output file name. Some platforms get "lib"
-  // prepended to library names. but be careful not to make a duplicate (e.g.
-  // some targets like "libxml" already have the "lib" in the name).
-  const char* prefix;
-  if (!target->settings()->IsWin() &&
-      (target->output_type() == Target::SHARED_LIBRARY ||
-       target->output_type() == Target::STATIC_LIBRARY) &&
-      name.compare(0, 3, "lib") != 0)
-    prefix = "lib";
-  else
-    prefix = "";
-
-  const char* extension;
-  if (target->output_extension().empty()) {
-    if (target->output_type() == Target::GROUP ||
-        target->output_type() == Target::SOURCE_SET ||
-        target->output_type() == Target::COPY_FILES ||
-        target->output_type() == Target::ACTION ||
-        target->output_type() == Target::ACTION_FOREACH) {
-      extension = "stamp";
-    } else {
-      extension = GetExtensionForOutputType(target->output_type(),
-                                            target->settings()->target_os());
-    }
-  } else {
-    extension = target->output_extension().c_str();
-  }
-
-  // Everything goes into the toolchain directory (which will be empty for the
-  // default toolchain, and will end in a slash otherwise).
-  ret.value().append(target->settings()->toolchain_output_subdir().value());
-
-  // Binaries and shared libraries go into the toolchain root.
-  if (target->output_type() == Target::EXECUTABLE ||
-      target->output_type() == Target::SHARED_LIBRARY) {
-    // Generate a name like "<toolchain>/<prefix><name>.<extension>".
-    ret.value().append(prefix);
-    ret.value().append(name);
-    if (extension[0]) {
-      ret.value().push_back('.');
-      ret.value().append(extension);
-    }
-    return ret;
-  }
-
-  // Everything else goes next to the target's .ninja file like
-  // "<toolchain>/obj/<path>/<name>.<extension>".
-  ret.value().append(kObjectDirNoSlash);
-  AppendStringPiece(&ret.value(),
-                    target->label().dir().SourceAbsoluteWithOneSlash());
-  ret.value().append(prefix);
-  ret.value().append(name);
-  if (extension[0]) {
-    ret.value().push_back('.');
-    ret.value().append(extension);
-  }
-  return ret;
-}
-
-std::string NinjaHelper::GetRulePrefix(const Settings* settings) const {
-  // Don't prefix the default toolchain so it looks prettier, prefix everything
-  // else.
-  if (settings->is_default())
-    return std::string();  // Default toolchain has no prefix.
-  return settings->toolchain_label().name() + "_";
-}
-
-std::string NinjaHelper::GetRuleForSourceType(const Settings* settings,
-                                              SourceFileType type) const {
-  // This function may be hot since it will be called for every source file
-  // in the tree. We could cache the results to avoid making a string for
-  // every invocation.
-  std::string prefix = GetRulePrefix(settings);
-
-  if (type == SOURCE_C)
-    return prefix + "cc";
-  if (type == SOURCE_CC)
-    return prefix + "cxx";
-  if (type == SOURCE_M)
-    return prefix + "objc";
-  if (type == SOURCE_MM)
-    return prefix + "objcxx";
-  if (type == SOURCE_RC)
-    return prefix + "rc";
-  if (type == SOURCE_S)
-    return prefix + "cc";  // Assembly files just get compiled by CC.
-
-  // TODO(brettw) asm files.
-
-  // .obj files have no rules to make them (they're already built) so we return
-  // the enpty string for SOURCE_O.
-  return std::string();
-}