Add initial prototype for the GN meta-buildsystem.

tools/gn/ninja_target_writer.cc

Index: tools/gn/ninja_target_writer.cc
diff --git a/tools/gn/ninja_target_writer.cc b/tools/gn/ninja_target_writer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ed2d09d06aece53432548738e0d70f158e3630ba
--- /dev/null
+++ b/tools/gn/ninja_target_writer.cc
@@ -0,0 +1,550 @@
+// 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_target_writer.h"
+
+#include <fstream>
+#include <sstream>
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "tools/gn/config_values_extractors.h"
+#include "tools/gn/err.h"
+#include "tools/gn/escape.h"
+#include "tools/gn/file_template.h"
+#include "tools/gn/location.h"
+#include "tools/gn/path_output.h"
+#include "tools/gn/scheduler.h"
+#include "tools/gn/string_utils.h"
+#include "tools/gn/target.h"
+
+namespace {
+
+static const char kCustomTargetSourceKey[] = "{{source}}";
+static const char kCustomTargetSourceNamePartKey[] = "{{source_name_part}}";
+
+struct DefineWriter {
+  void operator()(const std::string& s, std::ostream& out) const {
+    out << " -D" << s;
+  }
+};
+
+struct IncludeWriter {
+  IncludeWriter(PathOutput& path_output,
+                const NinjaHelper& h)
+      : helper(h),
+        path_output_(path_output),
+        old_inhibit_quoting_(path_output.inhibit_quoting()) {
+    // Inhibit quoting since we'll put quotes around the whole thing ourselves.
+    // Since we're writing in NINJA escaping mode, this won't actually do
+    // anything, but I think we may need to change to shell-and-then-ninja
+    // escaping for this in the future.
+    path_output_.set_inhibit_quoting(true);
+  }
+  ~IncludeWriter() {
+    path_output_.set_inhibit_quoting(old_inhibit_quoting_);
+  }
+
+  void operator()(const SourceDir& d, std::ostream& out) const {
+    out << " \"-I";
+    // It's important not to include the trailing slash on directories or on
+    // Windows it will be a backslash and the compiler might think we're
+    // escaping the quote!
+    path_output_.WriteDir(out, d, PathOutput::DIR_NO_LAST_SLASH);
+    out << "\"";
+  }
+
+  const NinjaHelper& helper;
+  PathOutput& path_output_;
+  bool old_inhibit_quoting_;  // So we can put the PathOutput back.
+};
+
+}  // namespace
+
+NinjaTargetWriter::NinjaTargetWriter(const Target* target, std::ostream& out)
+    : settings_(target->settings()),
+      target_(target),
+      out_(out),
+      path_output_(settings_->build_settings()->build_dir(),
+                   ESCAPE_NINJA, true),
+      helper_(settings_->build_settings()) {
+}
+
+NinjaTargetWriter::~NinjaTargetWriter() {
+}
+
+void NinjaTargetWriter::Run() {
+  out_ << "arch = environment.x86\n";
+
+  if (target_->output_type() == Target::COPY_FILES) {
+    WriteCopyRules();
+  } else if (target_->output_type() == Target::CUSTOM) {
+    WriteCustomRules();
+  } else {
+    WriteCompilerVars();
+
+    std::vector<OutputFile> obj_files;
+    WriteSources(&obj_files);
+
+    WriteLinkerStuff(obj_files);
+  }
+}
+
+// static
+void NinjaTargetWriter::RunAndWriteFile(const Target* target) {
+  if (target->output_type() == Target::NONE)
+    return;
+
+  const Settings* settings = target->settings();
+  NinjaHelper helper(settings->build_settings());
+
+  base::FilePath ninja_file(settings->build_settings()->GetFullPath(
+      helper.GetNinjaFileForTarget(target).GetSourceFile(
+          settings->build_settings())));
+
+  file_util::CreateDirectory(ninja_file.DirName());
+
+  // It's rediculously faster to write to a string and then write that to
+  // disk in one operation than to use an fstream here.
+  std::stringstream file;
+  if (file.fail()) {
+    g_scheduler->FailWithError(
+        Err(Location(), "Error writing ninja file.",
+            "Unable to open \"" + FilePathToUTF8(ninja_file) + "\"\n"
+            "for writing."));
+    return;
+  }
+
+  NinjaTargetWriter gen(target, file);
+  gen.Run();
+
+  std::string contents = file.str();
+  file_util::WriteFile(ninja_file, contents.c_str(), contents.size());
+}
+
+void NinjaTargetWriter::WriteCopyRules() {
+  // The dest dir should be inside the output dir so we can just remove the
+  // prefix and get ninja-relative paths.
+  const std::string& output_dir =
+      settings_->build_settings()->build_dir().value();
+  const std::string& dest_dir = target_->destdir().value();
+  DCHECK(StartsWithASCII(dest_dir, output_dir, true));
+  std::string relative_dest_dir(&dest_dir[output_dir.size()],
+                                dest_dir.size() - output_dir.size());
+
+  const Target::FileList& sources = target_->sources();
+  std::vector<OutputFile> dest_files;
+  dest_files.reserve(sources.size());
+
+  // Write out rules for each file copied.
+  for (size_t i = 0; i < sources.size(); i++) {
+    const SourceFile& input_file = sources[i];
+
+    // The files should have the same name but in the dest dir.
+    base::StringPiece name_part = FindFilename(&input_file.value());
+    OutputFile dest_file(relative_dest_dir);
+    AppendStringPiece(&dest_file.value(), name_part);
+
+    dest_files.push_back(dest_file);
+
+    out_ << "build ";
+    path_output_.WriteFile(out_, dest_file);
+    out_ << ": copy ";
+    path_output_.WriteFile(out_, input_file);
+    out_ << std::endl;
+  }
+
+  // Write out the rule for the target to copy all of them.
+  out_ << std::endl << "build ";
+  path_output_.WriteFile(out_, helper_.GetTargetOutputFile(target_));
+  out_ << ": stamp";
+  for (size_t i = 0; i < dest_files.size(); i++) {
+    out_ << " ";
+    path_output_.WriteFile(out_, dest_files[i]);
+  }
+  out_ << std::endl;
+
+  // TODO(brettw) need some kind of stamp file for depending on this, as well
+  // as order_only=prebuild.
+}
+
+void NinjaTargetWriter::WriteCustomRules() {
+  // Make a unique name for this rule.
+  std::string target_label = target_->label().GetUserVisibleName(true);
+  std::string custom_rule_name(target_label);
+  ReplaceChars(custom_rule_name, ":/()", "_", &custom_rule_name);
+  custom_rule_name.append("_rule");
+
+  // Run the script from the dir of the BUILD file. This has no trailing
+  // slash.
+  const SourceDir& script_cd = target_->label().dir();
+  std::string script_cd_to_root = InvertDir(script_cd);
+  if (script_cd_to_root.empty()) {
+    script_cd_to_root = ".";
+  } else {
+    // Remove trailing slash
+    DCHECK(script_cd_to_root[script_cd_to_root.size() - 1] == '/');
+    script_cd_to_root.resize(script_cd_to_root.size() - 1);
+  }
+
+  std::string script_relative_to_cd =
+      script_cd_to_root + target_->script().value();
+
+  bool no_sources = target_->sources().empty();
+
+  // Use a unique name for the response file when there are multiple build
+  // steps so that they don't stomp on each other.
+  std::string rspfile = custom_rule_name;
+  if (!no_sources)
+    rspfile += ".$unique_name";
+  rspfile += ".rsp";
+
+  // First write the custom rule.
+  out_ << "rule " << custom_rule_name << std::endl;
+  out_ << "  command = $pythonpath gyp-win-tool action-wrapper $arch "
+       << rspfile << " ";
+  path_output_.WriteDir(out_, script_cd, PathOutput::DIR_NO_LAST_SLASH);
+  out_ << std::endl;
+  out_ << "  description = CUSTOM " << target_label << std::endl;
+  out_ << "  restat = 1" << std::endl;
+  out_ << "  rspfile = " << rspfile << std::endl;
+
+  // The build command goes in the rsp file.
+  out_ << "  rspfile_content = $pythonpath " << script_relative_to_cd;
+  for (size_t i = 0; i < target_->script_args().size(); i++) {
+    const std::string& arg = target_->script_args()[i];
+    out_ << " ";
+    WriteCustomArg(arg);
+  }
+  out_ << std::endl << std::endl;
+
+  // Precompute the common dependencies for each step. This includes the
+  // script itself (changing the script should force a rebuild) and any data
+  // files.
+  std::ostringstream common_deps_stream;
+  path_output_.WriteFile(common_deps_stream, target_->script());
+  const Target::FileList& datas = target_->data();
+  for (size_t i = 0; i < datas.size(); i++) {
+    common_deps_stream << " ";
+    path_output_.WriteFile(common_deps_stream, datas[i]);
+  }
+  const std::string& common_deps = common_deps_stream.str();
+
+  // Collects all output files for writing below.
+  std::vector<OutputFile> output_files;
+
+  if (no_sources) {
+    // No sources, write a rule that invokes the script once with the
+    // outputs as outputs, and the data as inputs.
+    out_ << "build";
+    const Target::FileList& outputs = target_->outputs();
+    for (size_t i = 0; i < outputs.size(); i++) {
+      OutputFile output_path(
+          RemovePrefix(outputs[i].value(),
+                       settings_->build_settings()->build_dir().value()));
+      output_files.push_back(output_path);
+      out_ << " ";
+      path_output_.WriteFile(out_, output_path);
+    }
+    out_ << ": " << custom_rule_name << " " << common_deps << std::endl;
+  } else {
+    // Write separate rules for each input source file.
+    WriteCustomSourceRules(custom_rule_name, common_deps, script_cd,
+                           script_cd_to_root, &output_files);
+  }
+  out_ << std::endl;
+
+  // Last write a stamp rule to collect all outputs.
+  out_ << "build ";
+  path_output_.WriteFile(out_, helper_.GetTargetOutputFile(target_));
+  out_ << ": stamp";
+  for (size_t i = 0; i < output_files.size(); i++) {
+    out_ << " ";
+    path_output_.WriteFile(out_, output_files[i]);
+  }
+  out_ << std::endl;
+}
+
+void NinjaTargetWriter::WriteCustomArg(const std::string& arg) {
+  // This can be optimized if it's called a lot.
+  EscapeOptions options;
+  options.mode = ESCAPE_NINJA;
+  std::string output_str = EscapeString(arg, options);
+
+  // Do this substitution after escaping our our $ will be escaped (which we
+  // don't want).
+  ReplaceSubstringsAfterOffset(&output_str, 0, FileTemplate::kSource,
+                               "${source}");
+  ReplaceSubstringsAfterOffset(&output_str, 0, FileTemplate::kSourceNamePart,
+                               "${source_name_part}");
+  out_ << output_str;
+}
+
+void NinjaTargetWriter::WriteCustomSourceRules(
+    const std::string& custom_rule_name,
+    const std::string& common_deps,
+    const SourceDir& script_cd,
+    const std::string& script_cd_to_root,
+    std::vector<OutputFile>* output_files) {
+  // Construct the template for generating the output files from each source.
+  const Target::FileList& outputs = target_->outputs();
+  std::vector<std::string> output_template_args;
+  for (size_t i = 0; i < outputs.size(); i++) {
+    // All outputs should be in the output dir.
+    output_template_args.push_back(
+        RemovePrefix(outputs[i].value(),
+                     settings_->build_settings()->build_dir().value()));
+  }
+  FileTemplate output_template(output_template_args);
+
+  // Prevent re-allocating each time by initializing outside the loop.
+  std::vector<std::string> output_template_result;
+
+  // Path output formatter for wrigin source paths passed to the script.
+  PathOutput script_source_path_output(script_cd, ESCAPE_SHELL, true);
+
+  const Target::FileList& sources = target_->sources();
+  for (size_t i = 0; i < sources.size(); i++) {
+    // Write outputs for this source file computed by the template.
+    out_ << "build";
+    output_template.ApplyString(sources[i].value(), &output_template_result);
+    for (size_t out_i = 0; out_i < output_template_result.size(); out_i++) {
+      OutputFile output_path(output_template_result[out_i]);
+      output_files->push_back(output_path);
+      out_ << " ";
+      path_output_.WriteFile(out_, output_path);
+    }
+
+    out_ << ": " << custom_rule_name
+         << " " << common_deps
+         << " ";
+    path_output_.WriteFile(out_, sources[i]);
+    out_ << std::endl;
+
+    out_ << "  unique_name = " << i << std::endl;
+
+    // The source file here should be relative to the script directory since
+    // this is the variable passed to the script. Here we slightly abuse the
+    // OutputFile object by putting a non-output-relative path in it to signal
+    // that the PathWriter should not prepend directories.
+    out_ << "  source = ";
+    script_source_path_output.WriteFile(out_, sources[i]);
+    out_ << std::endl;
+
+    out_ << "  source_name_part = "
+         << FindFilenameNoExtension(&sources[i].value()).as_string()
+         << std::endl;
+  }
+}
+
+void NinjaTargetWriter::WriteCompilerVars() {
+  // Defines.
+  out_ << "defines =";
+  RecursiveTargetConfigToStream(target_, &ConfigValues::defines,
+                                DefineWriter(), out_);
+  out_ << std::endl;
+
+  // Includes.
+  out_ << "includes =";
+  RecursiveTargetConfigToStream(target_, &ConfigValues::includes,
+                                IncludeWriter(path_output_, helper_), out_);
+
+  out_ << std::endl;
+
+  // C flags and friends.
+  out_ << "cflags =";
+  RecursiveTargetConfigStringsToStream(target_, &ConfigValues::cflags, out_);
+  out_ << std::endl;
+  out_ << "cflags_c =";
+  RecursiveTargetConfigStringsToStream(target_, &ConfigValues::cflags_c, out_);
+  out_ << std::endl;
+  out_ << "cflags_cc =";
+  RecursiveTargetConfigStringsToStream(target_, &ConfigValues::cflags_cc, out_);
+  out_ << std::endl;
+
+  out_ << std::endl;
+}
+
+void NinjaTargetWriter::WriteSources(
+    std::vector<OutputFile>* object_files) {
+  const Target::FileList& sources = target_->sources();
+  object_files->reserve(sources.size());
+
+  for (size_t i = 0; i < sources.size(); i++) {
+    const SourceFile& input_file = sources[i];
+
+    SourceFileType input_file_type = GetSourceFileType(input_file,
+                                                       settings_->target_os());
+    if (input_file_type == SOURCE_UNKNOWN)
+      continue;  // Skip unknown file types.
+    const char* command = GetCommandForSourceType(input_file_type);
+    if (!command)
+      continue;  // Skip files not needing compilation.
+
+    OutputFile output_file = helper_.GetOutputFileForSource(
+        target_, input_file, input_file_type);
+    object_files->push_back(output_file);
+
+    out_ << "build ";
+    path_output_.WriteFile(out_, output_file);
+    out_ << ": " << command << " ";
+    path_output_.WriteFile(out_, input_file);
+    out_ << std::endl;
+  }
+  out_ << std::endl;
+}
+
+void NinjaTargetWriter::WriteLinkerStuff(
+    const std::vector<OutputFile>& object_files) {
+  // Manifest file on Windows.
+  // TODO(brettw) this seems not to be necessary for static libs, skip in
+  // that case?
+  OutputFile windows_manifest;
+  if (settings_->IsWin()) {
+    windows_manifest.value().assign(helper_.GetTargetOutputDir(target_));
+    windows_manifest.value().append(target_->label().name());
+    windows_manifest.value().append(".intermediate.manifest");
+    out_ << "manifests = ";
+    path_output_.WriteFile(out_, windows_manifest);
+    out_ << std::endl;
+  }
+
+  // Linker flags, append manifest flag on Windows to reference our file.
+  out_ << "ldflags =";
+  RecursiveTargetConfigStringsToStream(target_, &ConfigValues::ldflags, out_);
+  if (settings_->IsWin())
+    out_ << " /MANIFEST /ManifestFile:";
+    path_output_.WriteFile(out_, windows_manifest);
+  {  // HACK ERASEME BRETTW FIXME
+    out_ << " /DEBUG /MACHINE:X86 /LIBPATH:\"C:\\Program Files (x86)\\Windows Kits\\8.0\\Lib\\win8\\um\\x86\" /DELAYLOAD:dbghelp.dll /DELAYLOAD:dwmapi.dll /DELAYLOAD:shell32.dll /DELAYLOAD:uxtheme.dll /safeseh /dynamicbase /ignore:4199 /ignore:4221 /nxcompat /SUBSYSTEM:CONSOLE /INCREMENTAL /FIXED:NO /DYNAMICBASE:NO wininet.lib dnsapi.lib version.lib msimg32.lib ws2_32.lib usp10.lib psapi.lib dbghelp.lib winmm.lib shlwapi.lib kernel32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib user32.lib uuid.lib odbc32.lib odbccp32.lib delayimp.lib /NXCOMPAT";
+  }
+  out_ << std::endl;
+
+  // Libraries to link.
+  out_ << "libs =" << std::endl;
+
+  // The external output file is the one that other libs depend on.
+  OutputFile external_output_file = helper_.GetTargetOutputFile(target_);
+
+  // The internal output file is the "main thing" we think we're making. In
+  // the case of shared libraries, this is the shared library and the external
+  // output file is the import library. In other cases, the internal one and
+  // the external one are the same.
+  OutputFile internal_output_file;
+  if (target_->output_type() == Target::SHARED_LIBRARY) {
+    if (settings_->IsWin()) {
+      internal_output_file = OutputFile(target_->label().name() + ".dll");
+    } else {
+      NOTREACHED();  // TODO(brettw) write this.
+    }
+  } else {
+    internal_output_file = external_output_file;
+  }
+
+  // TODO(brettw) should we append data files to this?
+
+  // In Python see "self.ninja.build(output, command, input,"
+  out_ << "build ";
+  path_output_.WriteFile(out_, internal_output_file);
+  if (external_output_file != internal_output_file) {
+    out_ << " ";
+    path_output_.WriteFile(out_, external_output_file);
+  }
+  out_ << ": " << GetCommandForTargetType();
+  for (size_t i = 0; i < object_files.size(); i++) {
+    out_ << " ";
+    path_output_.WriteFile(out_, object_files[i]);
+  }
+
+  if (target_->output_type() == Target::EXECUTABLE ||
+      target_->output_type() == Target::SHARED_LIBRARY ||
+      target_->output_type() == Target::LOADABLE_MODULE) {
+    const std::vector<const Target*>& deps = target_->deps();
+    const std::set<const Target*>& inherited = target_->inherited_libraries();
+
+    // Now append linkable libraries to the linker command.
+    for (size_t i = 0; i < deps.size(); i++) {
+      if (deps[i]->IsLinkable() &&
+          inherited.find(deps[i]) == inherited.end()) {
+        out_ << " ";
+        path_output_.WriteFile(out_,
+                               helper_.GetTargetOutputFile(target_->deps()[i]));
+      }
+    }
+    for (std::set<const Target*>::const_iterator i = inherited.begin();
+         i != inherited.end(); ++i) {
+      out_ << " ";
+      path_output_.WriteFile(out_, helper_.GetTargetOutputFile(*i));
+    }
+  }
+  out_ << std::endl;
+
+  if (target_->output_type() == Target::SHARED_LIBRARY) {
+    out_ << "  soname = ";
+    path_output_.WriteFile(out_, internal_output_file);
+    out_ << std::endl;
+
+    out_ << "  lib = ";
+    path_output_.WriteFile(out_, internal_output_file);
+    out_ << std::endl;
+
+    out_ << "  dll = ";
+    path_output_.WriteFile(out_, internal_output_file);
+    out_ << std::endl;
+
+    if (settings_->IsWin()) {
+      out_ << "  implibflag = /IMPLIB:";
+      path_output_.WriteFile(out_, external_output_file);
+      out_ << std::endl;
+    }
+  }
+
+  // TODO(brettw) postbuild steps here.
+
+  out_ << std::endl;
+}
+
+const char* NinjaTargetWriter::GetCommandForSourceType(
+    SourceFileType type) const {
+  if (type == SOURCE_C)
+    return "cc";
+  if (type == SOURCE_CC)
+    return "cxx";
+
+  // TODO(brettw) asm files.
+
+  if (settings_->IsMac()) {
+    if (type == SOURCE_M)
+      return "objc";
+    if (type == SOURCE_MM)
+      return "objcxx";
+  }
+
+  if (settings_->IsWin()) {
+    if (type == SOURCE_RC)
+      return "rc";
+  }
+
+  // TODO(brettw) stuff about "S" files on non-Windows.
+  return NULL;
+}
+
+const char* NinjaTargetWriter::GetCommandForTargetType() const {
+  if (target_->output_type() == Target::NONE) {
+    NOTREACHED();
+    return "";
+  }
+
+  if (target_->output_type() == Target::STATIC_LIBRARY) {
+    // TODO(brettw) stuff about standalong static libraryes on Unix in
+    // WriteTarget in the Python one, and lots of postbuild steps.
+    return "alink";
+  }
+
+  if (target_->output_type() == Target::SHARED_LIBRARY)
+    return "solink";
+
+  return "link";
+}