gn: Support build directories outside the source tree.

tools/gn/function_rebase_path.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 "tools/gn/build_settings.h"
 #include "tools/gn/filesystem_utils.h"
 #include "tools/gn/functions.h"
 #include "tools/gn/parse_tree.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/settings.h"
@@ skipping 53 matching lines @@
     return result;
   const std::string& string_value = value.string_value();
 
   bool looks_like_dir = ValueLooksLikeDir(string_value);
 
   // System-absolute output special case.
   if (convert_to_system_absolute) {
     base::FilePath system_path;
     if (looks_like_dir) {
       system_path = scope->settings()->build_settings()->GetFullPath(
-          from_dir.ResolveRelativeDir(string_value));
+          from_dir.ResolveRelativeDir(string_value,
+              scope->settings()->build_settings()->root_path()));
     } else {
       system_path = scope->settings()->build_settings()->GetFullPath(
-          from_dir.ResolveRelativeFile(string_value));
+          from_dir.ResolveRelativeFile(string_value,
+              scope->settings()->build_settings()->root_path()));
     }
     result = Value(function, FilePathToUTF8(system_path));
     if (looks_like_dir)
       MakeSlashEndingMatchInput(string_value, &result.string_value());
     return result;
   }
 
-  if (from_dir.is_system_absolute() || to_dir.is_system_absolute()) {
-    *err = Err(function, "System-absolute directories are not supported for "
-        "the source or dest dir for rebase_path. It would be nice to add this "
-        "if you're so inclined!");
-    return result;
-  }
-
   result = Value(function, Value::STRING);
   if (looks_like_dir) {
     result.string_value() = RebaseSourceAbsolutePath(
-        from_dir.ResolveRelativeDir(string_value).value(),
-        to_dir);
+        from_dir.ResolveRelativeDir(string_value,
+            scope->settings()->build_settings()->root_path()).value(),
+        to_dir,
+        scope->settings()->build_settings()->root_path());
     MakeSlashEndingMatchInput(string_value, &result.string_value());
   } else {
     result.string_value() = RebaseSourceAbsolutePath(
-        from_dir.ResolveRelativeFile(string_value).value(),
-        to_dir);
+        from_dir.ResolveRelativeFile(string_value,
+            scope->settings()->build_settings()->root_path()).value(),
+        to_dir,
+        scope->settings()->build_settings()->root_path());
   }
 
   return result;
 }
 
 }  // namespace
 
 const char kRebasePath[] = "rebase_path";
 const char kRebasePath_HelpShort[] =
     "rebase_path: Rebase a file or directory to another location.";
@@ skipping 114 matching lines @@
   const Value& inputs = args[kArgIndexInputs];
 
   // To path.
   bool convert_to_system_absolute = true;
   SourceDir to_dir;
   const SourceDir& current_dir = scope->GetSourceDir();
   if (args.size() > kArgIndexDest) {
     if (!args[kArgIndexDest].VerifyTypeIs(Value::STRING, err))
       return result;
     if (!args[kArgIndexDest].string_value().empty()) {
-      to_dir =
-          current_dir.ResolveRelativeDir(args[kArgIndexDest].string_value());
+      to_dir = current_dir.ResolveRelativeDir(
+          args[kArgIndexDest].string_value(),
+          scope->settings()->build_settings()->root_path());
       convert_to_system_absolute = false;
     }
   }
 
   // From path.
   SourceDir from_dir;
   if (args.size() > kArgIndexFrom) {
     if (!args[kArgIndexFrom].VerifyTypeIs(Value::STRING, err))
       return result;
-    from_dir =
-        current_dir.ResolveRelativeDir(args[kArgIndexFrom].string_value());
+    from_dir = current_dir.ResolveRelativeDir(
+        args[kArgIndexFrom].string_value(),
+        scope->settings()->build_settings()->root_path());
   } else {
     // Default to current directory if unspecified.
     from_dir = current_dir;
   }
 
   // Path conversion.
   if (inputs.type() == Value::STRING) {
     return ConvertOnePath(scope, function, inputs,
                           from_dir, to_dir, convert_to_system_absolute, err);
 
@@ skipping 12 matching lines @@
     }
     return result;
   }
 
   *err = Err(function->function(),
              "rebase_path requires a list or a string.");
   return result;
 }
 
 }  // namespace functions