Server push cancellation: add a new class HttpCacheLookupManager which implements ServerPushDelegate

net/http/http_cache_lookup_manager.cc

Index: net/http/http_cache_lookup_manager.cc
diff --git a/net/http/http_cache_lookup_manager.cc b/net/http/http_cache_lookup_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b1d822fa56eb6ef2520fa6dafc6dfed33b7c365e
--- /dev/null
+++ b/net/http/http_cache_lookup_manager.cc
@@ -0,0 +1,71 @@
+// Copyright 2016 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 "net/http/http_cache_lookup_manager.h"
+
+#include "net/base/load_flags.h"
+
+namespace net {
+
+HttpCacheLookupManager::LookupTransaction::LookupTransaction(
+    std::unique_ptr<ServerPushHelper> server_push_helper)
+    : push_helper(std::move(server_push_helper)),
+      request(new HttpRequestInfo()),
+      transaction(nullptr) {}
+
+HttpCacheLookupManager::LookupTransaction::~LookupTransaction() {}
+
+int HttpCacheLookupManager::LookupTransaction::StartLookup(
+    HttpCache* cache,
+    const CompletionCallback& callback,
+    const NetLogWithSource& net_log) {
+  request->url = push_helper->GetURL();
+  request->method = "GET";
+  request->load_flags = LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
+  cache->CreateTransaction(DEFAULT_PRIORITY, &transaction);
+  return transaction->Start(request.get(), callback, net_log);
+}
+
+void HttpCacheLookupManager::LookupTransaction::CancelPush() {
+  DCHECK(push_helper.get());
+  push_helper->Cancel();
+}
+
+HttpCacheLookupManager::HttpCacheLookupManager(HttpCache* http_cache,
+                                               const NetLogWithSource& net_log)
+    : net_log_(net_log), http_cache_(http_cache), weak_factory_(this) {}
+
+HttpCacheLookupManager::~HttpCacheLookupManager() {}
+
+void HttpCacheLookupManager::OnPush(
+    std::unique_ptr<ServerPushHelper> push_helper) {
+  GURL pushed_url = push_helper->GetURL();
+
+  // There's a pending lookup transaction sent over already.
+  if (lookup_transactions_.find(pushed_url) != lookup_transactions_.end())

[Ryan Hamilton, 2016/11/18 20:47:02]

nit: if (ContainsKey(lookup_transactions_, pushed_url)) {

[Zhongyi Shi, 2016/11/19 05:07:12]

Done.

+    return;
+
+  auto lookup = base::MakeUnique<LookupTransaction>(std::move(push_helper));
+
+  int rv = lookup->StartLookup(
+      http_cache_, base::Bind(&HttpCacheLookupManager::OnLookupComplete,
+                              weak_factory_.GetWeakPtr(), pushed_url),
+      net_log_);
+
+  if (rv == ERR_IO_PENDING) {
+    lookup_transactions_[pushed_url] = std::move(lookup);
+  }

[Ryan Hamilton, 2016/11/18 20:47:02]

nit: no {}s on 1-line ifs

[Zhongyi Shi, 2016/11/19 05:07:12]

Done.

+}

[Ryan Hamilton, 2016/11/18 20:47:02]

This method looks really clean now!

+
+void HttpCacheLookupManager::OnLookupComplete(const GURL& url, int rv) {
+  auto it = lookup_transactions_.find(url);
+  DCHECK(it != lookup_transactions_.end());
+
+  if (rv == OK)
+    it->second->CancelPush();
+
+  lookup_transactions_.erase(it);
+}
+
+}  // namespace net