Support more configurability in GN toolchains

tools/gn/substitution_pattern.cc

 // Copyright 2014 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/substitution_pattern.h"
 
 #include "base/strings/string_number_conversions.h"
+#include "tools/gn/build_settings.h"
 #include "tools/gn/err.h"
+#include "tools/gn/filesystem_utils.h"
 #include "tools/gn/value.h"
 
 SubstitutionPattern::Subrange::Subrange()
     : type(SUBSTITUTION_LITERAL) {
 }
 
 SubstitutionPattern::Subrange::Subrange(SubstitutionType t,
                                         const std::string& l)
     : type(t),
       literal(l) {
 }
 
 SubstitutionPattern::Subrange::~Subrange() {
 }
 
-SubstitutionPattern::SubstitutionPattern() {
+SubstitutionPattern::SubstitutionPattern() : origin_(NULL) {
 }
 
 SubstitutionPattern::~SubstitutionPattern() {
 }
 
 bool SubstitutionPattern::Parse(const Value& value, Err* err) {
   if (!value.VerifyTypeIs(Value::STRING, err))
     return false;
   return Parse(value.string_value(), value.origin(), err);
 }
@@ skipping 38 matching lines @@
       // to exactly indicate the error location is tricky.
       *err = Err(origin, "Unknown substitution pattern",
           "Found a {{ at offset " +
           base::SizeTToString(next) +
           " and did not find a known substitution following it.");
       ranges_.clear();
       return false;
     }
   }
 
+  origin_ = origin;
+
   // Fill required types vector.
-  bool required_type_bits[SUBSTITUTION_NUM_TYPES] = {0};
-  FillRequiredTypes(required_type_bits);
-
-  for (size_t i = SUBSTITUTION_FIRST_PATTERN; i < SUBSTITUTION_NUM_TYPES; i++) {
-    if (required_type_bits[i])
-      required_types_.push_back(static_cast<SubstitutionType>(i));
-  }
+  SubstitutionBits bits;
+  FillRequiredTypes(&bits);
+  bits.FillVector(&required_types_);
   return true;
 }
 
 std::string SubstitutionPattern::AsString() const {
   std::string result;
   for (size_t i = 0; i < ranges_.size(); i++) {
     if (ranges_[i].type == SUBSTITUTION_LITERAL)
       result.append(ranges_[i].literal);
     else
       result.append(kSubstitutionNames[ranges_[i].type]);
   }
   return result;
 }
 
-void SubstitutionPattern::FillRequiredTypes(
-    bool required_types[SUBSTITUTION_NUM_TYPES]) const {
+void SubstitutionPattern::FillRequiredTypes(SubstitutionBits* bits) const {
   for (size_t i = 0; i < ranges_.size(); i++) {
     if (ranges_[i].type != SUBSTITUTION_LITERAL)
-      required_types[static_cast<size_t>(ranges_[i].type)] = true;
+      bits->used[static_cast<size_t>(ranges_[i].type)] = true;
   }
 }
+
+bool SubstitutionPattern::IsInOutputDir(const BuildSettings* build_settings,
+                                        Err* err) const {
+  if (ranges_.empty()) {
+    *err = Err(origin_, "This is empty but I was expecting an output file.");
+    return false;
+  }
+
+  if (ranges_[0].type == SUBSTITUTION_LITERAL) {
+    // If the first thing is a literal, it must start with the output dir.
+    if (!EnsureStringIsInOutputDir(
+            build_settings->build_dir(),
+            ranges_[0].literal, origin_, err))
+      return false;
+  } else {
+    // Otherwise, the first subrange must be a pattern that expands to
+    // something in the output directory.
+    if (!SubstitutionIsInOutputDir(ranges_[0].type)) {
+      *err = Err(origin_,
+          "File is not inside output directory.",
+          "The given file should be in the output directory. Normally you\n"
+          "would specify\n\"$target_out_dir/foo\" or "
+          "\"{{source_gen_dir}}/foo\".");
+      return false;
+    }
+  }
+
+  return true;
+}