ServiceWorker: Support longest-prefix-match for registration scope

content/browser/service_worker/service_worker_utils.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 "content/browser/service_worker/service_worker_utils.h"
 
+#include <string>
+
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "content/public/common/content_switches.h"
+#include "url/gurl.h"
 
 namespace content {
 
 // static
 bool ServiceWorkerUtils::IsFeatureEnabled() {
   static bool enabled = CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableServiceWorker);
   return enabled;
 }
 
 // static
 bool ServiceWorkerUtils::ScopeMatches(const GURL& scope, const GURL& url) {
   DCHECK(!scope.has_ref());
   DCHECK(!url.has_ref());
   const std::string& scope_spec = scope.spec();
   const std::string& url_spec = url.spec();
 
   size_t len = scope_spec.size();
   if (len > 0 && scope_spec[len - 1] == '*')
     return scope_spec.compare(0, len - 1, url_spec, 0, len - 1) == 0;
   return scope_spec == url_spec;
 }
 
+bool LongestScopeMatcher::MatchLongest(const GURL& scope) {
+  if (!ServiceWorkerUtils::ScopeMatches(scope, url_))
+    return false;
+  if (match_.is_empty()) {
+    match_ = scope;
+    return true;
+  }
+
+  const std::string match_spec = match_.spec();
+  const std::string scope_spec = scope.spec();
+  if (match_spec.size() < scope_spec.size()) {
+    match_ = scope;
+    return true;
+  }
+
+  // If |scope| has the same length with |match_|, they are compared as strings.
+  // For example:
+  //   1) for a document "/foo", "/foo" is prioritized over "/fo*".
+  //   2) for a document "/f(1)", "/f(1*" is prioritized over "/f(1)".
+  // TODO(nhiroki): This isn't in the spec.
+  // (https://github.com/slightlyoff/ServiceWorker/issues/287)
+  if (match_spec.size() == scope_spec.size() && match_spec < scope_spec) {
+    match_ = scope;
+    return true;
+  }
+
+  return false;
+}
+
 }  // namespace content