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

net/http/http_cache_lookup_manager.cc

+// 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) {
+  request->url = push_helper->GetURL();
+  request->method = "GET";
+  request->load_flags = LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
+}
+
+HttpCacheLookupManager::LookupTransaction::~LookupTransaction() {}
+
+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())
+    return;
+
+  auto lookup = base::MakeUnique<LookupTransaction>(std::move(push_helper));
+
+  int rv =
+      http_cache_->CreateTransaction(DEFAULT_PRIORITY, &lookup->transaction);
+  if (rv != OK)

[Ryan Hamilton, 2016/11/17 22:47:24]

Can this return ERR_IO_PENDING? It looks like no. how 'bout:

 DCHECK_NE(ERR_IO_PENDING, rv);

[Zhongyi Shi, 2016/11/18 20:34:19]

Actually, the only response from CreateTransaction should be OK. That implies we
could just skip checking.

+    return;
+
+  rv = lookup->transaction->Start(
+      lookup->request.get(),
+      base::Bind(&HttpCacheLookupManager::OnPushFilteringComplete,
+                 weak_factory_.GetWeakPtr(), pushed_url),
+      net_log_);
+
+  if (rv == ERR_IO_PENDING) {
+    lookup_transactions_[pushed_url] = std::move(lookup);
+  }
+}
+
+void HttpCacheLookupManager::OnPushFilteringComplete(const GURL& url, int rv) {
+  auto it = lookup_transactions_.find(url);
+  DCHECK(it != lookup_transactions_.end());
+
+  if (rv == OK)
+    it->second->push_helper->Cancel();
+
+  lookup_transactions_.erase(it);
+}
+
+}  // namespace net