Enforce the 'requirements' field in manifests.

chrome/browser/extensions/requirements_provider_impl.cc

+// Copyright (c) 2012 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 "chrome/browser/extensions/requirements_provider_impl.h"
+
+#include "base/string16.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/common/extensions/extension_manifest_constants.h"
+#include "chrome/common/extensions/manifest.h"
+
+namespace keys = extension_manifest_keys;
+
+namespace extensions {
+
+// static
+RequirementsProvider* RequirementsProvider::Create() {
+  return new RequirementsProviderImpl();
+}
+
+RequirementsProviderImpl::RequirementsProviderImpl() {
+}
+
+bool RequirementsProviderImpl::Supports(const Manifest& manifest,
+                                        string16* error) {
+  DictionaryValue* requirements_value = NULL;
+  manifest.GetDictionary(keys::kRequirements, &requirements_value);
+  if (!requirements_value)
+    return true;
+
+  for (DictionaryValue::key_iterator it = requirements_value->begin_keys();
+       it != requirements_value->end_keys(); ++it) {
+    DictionaryValue* requirement_value;
+    requirements_value->GetDictionaryWithoutPathExpansion(
+        *it, &requirement_value);
+    if (!requirement_value)
+      continue;
+
+    if (*it == "plugins") {
+#if defined(OS_CHROMEOS)
+      // TODO(eriq): i18n
+      *error = ASCIIToUTF16("Plugins are not supported on CHROMEOS");
+      return false;
+#endif
+    } else if (*it == "foo") {
+      ListValue* features;
+      requirement_value->GetListWithoutPathExpansion("features", &features);
+      if (!features)
+        continue;
+      std::string feature;
+      features->GetString(0, &feature);
+      if (feature != "bar") {
+        *error = ASCIIToUTF16(
+            "Requirement 'foo' only supports the feature 'bar'");
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+}  // namespace extensions