Adds a new class HttpCache::Writers for multiple cache transactions reading from the network.

net/http/http_cache_unittest.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 "net/http/http_cache.h"
 
 #include <stdint.h>
 
 #include <algorithm>
 #include <memory>
@@ skipping 200 matching lines @@
   // write to the cache
 
   std::unique_ptr<HttpTransaction> trans;
   int rv = cache->CreateTransaction(DEFAULT_PRIORITY, &trans);
   EXPECT_THAT(rv, IsOk());
   ASSERT_TRUE(trans.get());
 
   rv = trans->Start(&request, callback.callback(), net_log);
   if (rv == ERR_IO_PENDING)
     rv = callback.WaitForResult();
-  ASSERT_EQ(trans_info.return_code, rv);
+  ASSERT_EQ(trans_info.start_return_code, rv);
 
   if (OK != rv)
     return;
 
   const HttpResponseInfo* response = trans->GetResponseInfo();
   ASSERT_TRUE(response);
 
   if (response_info)
     *response_info = *response;
 
@@ skipping 837 matching lines @@
   MockTransaction transaction(kSimpleGET_Transaction);
   transaction.response_headers = "Cache-Control: no-cache\n";
 
   AddMockTransaction(&transaction);
   RunTransactionTest(cache.http_cache(), transaction);
   EXPECT_EQ(1, cache.network_layer()->transaction_count());
   EXPECT_EQ(1, cache.disk_cache()->create_count());
   RemoveMockTransaction(&transaction);
 
   // Network failure with error; should fail but have was_cached set.
-  transaction.return_code = ERR_FAILED;
+  transaction.start_return_code = ERR_FAILED;
   AddMockTransaction(&transaction);
 
   MockHttpRequest request(transaction);
   TestCompletionCallback callback;
   std::unique_ptr<HttpTransaction> trans;
   int rv = cache.http_cache()->CreateTransaction(DEFAULT_PRIORITY, &trans);
   EXPECT_THAT(rv, IsOk());
   ASSERT_TRUE(trans.get());
   rv = trans->Start(&request, callback.callback(), NetLogWithSource());
   EXPECT_THAT(callback.GetResult(rv), IsError(ERR_FAILED));
@@ skipping 790 matching lines @@
   }
 
   // Allow all requests to move from the Create queue to the active entry.
   base::RunLoop().RunUntilIdle();
 
   // The first request should be a writer at this point, and the subsequent
   // requests should have passed the validation phase and created their own
   // entries since none of them matched the headers of the earlier one.
   EXPECT_TRUE(cache.IsWriterPresent(kSimpleGET_Transaction.url));
 
-  // Note that there are only 3 entries created and not 5 since every other
-  // transaction would have gone to the network.
   EXPECT_EQ(5, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
-  EXPECT_EQ(3, cache.disk_cache()->create_count());
+  EXPECT_EQ(5, cache.disk_cache()->create_count());
 
   // All requests depend on the writer, and the writer is between Start and
   // Read, i.e. idle.
   for (auto& context : context_list) {
     EXPECT_EQ(LOAD_STATE_IDLE, context->trans->GetLoadState());
   }
 
   for (auto& context : context_list) {
     if (context->result == ERR_IO_PENDING)
       context->result = context->callback.WaitForResult();
     ReadAndVerifyTransaction(context->trans.get(), kSimpleGET_Transaction);
   }
 
   EXPECT_EQ(5, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
-  EXPECT_EQ(3, cache.disk_cache()->create_count());
+  EXPECT_EQ(5, cache.disk_cache()->create_count());
+}
+
+// Parallel validation results in 200 for 1 transaction and validation matches
+// for subsequent transactions.
+TEST(HttpCache, SimpleGET_ParallelValidationNoMatch1) {
+  MockHttpCache cache;
+  MockHttpRequest request(kSimpleGET_Transaction);
+
+  MockTransaction transaction(kSimpleGET_Transaction);
+  transaction.load_flags |= LOAD_VALIDATE_CACHE;
+  MockHttpRequest validate_request(transaction);
+  std::vector<std::unique_ptr<Context>> context_list;
+  const int kNumTransactions = 5;
+  for (int i = 0; i < kNumTransactions; ++i) {
+    context_list.push_back(base::MakeUnique<Context>());
+    auto& c = context_list[i];
+    c->result = cache.CreateTransaction(&c->trans);
+    ASSERT_THAT(c->result, IsOk());
+    EXPECT_EQ(LOAD_STATE_IDLE, c->trans->GetLoadState());
+
+    MockHttpRequest* this_request = &request;
+    if (i == 1)
+      this_request = &validate_request;
+
+    c->result = c->trans->Start(this_request, c->callback.callback(),
+                                NetLogWithSource());
+  }
+
+  // All requests are waiting for the active entry.
+  for (auto& context : context_list) {
+    EXPECT_EQ(LOAD_STATE_WAITING_FOR_CACHE, context->trans->GetLoadState());
+  }
+
+  // Allow all requests to move from the Create queue to the active entry.
+  base::RunLoop().RunUntilIdle();
+
+  // The first request should be a writer at this point, and the second
+  // request should have passed the validation phase and created a new
+  // entry. Rest of them should be added to the new entry.
+  EXPECT_TRUE(cache.IsWriterPresent(kSimpleGET_Transaction.url));
+  EXPECT_EQ(3, cache.GetCountDoneHeadersQueue(kSimpleGET_Transaction.url));
+
+  EXPECT_EQ(2, cache.network_layer()->transaction_count());
+  EXPECT_EQ(0, cache.disk_cache()->open_count());
+  EXPECT_EQ(2, cache.disk_cache()->create_count());
+
+  // All requests depend on the writer, and the writer is between Start and
+  // Read, i.e. idle.
+  for (auto& context : context_list) {
+    EXPECT_EQ(LOAD_STATE_IDLE, context->trans->GetLoadState());
+  }
+
+  EXPECT_EQ(1, cache.disk_cache()->doomed_count());
+
+  for (size_t i = 0; i < context_list.size(); i++) {
+    if (context_list[i]->result == ERR_IO_PENDING)
+      context_list[i]->result = context_list[i]->callback.WaitForResult();
+
+    ReadAndVerifyTransaction(context_list[i]->trans.get(),
+                             kSimpleGET_Transaction);
+  }
+
+  EXPECT_EQ(2, cache.network_layer()->transaction_count());
+  EXPECT_EQ(0, cache.disk_cache()->open_count());
+  EXPECT_EQ(2, cache.disk_cache()->create_count());
 }
 
 // Tests that a GET followed by a DELETE results in DELETE immediately starting
 // the headers phase and the entry is doomed.
 TEST(HttpCache, SimpleGET_ParallelValidationDelete) {
   MockHttpCache cache;
 
   MockHttpRequest request(kSimpleGET_Transaction);
   request.load_flags |= LOAD_VALIDATE_CACHE;
 
@@ skipping 228 matching lines @@
   EXPECT_TRUE(cache.IsHeadersTransactionPresent(kSimpleGET_Transaction.url));
 
   // Resume network start for headers_transaction. It will doom the entry as it
   // will be a 200 and will go to network for the response body.
   auto& context = context_list[3];
   context->trans->ResumeNetworkStart();
 
   // The pending transactions will be added to a new entry.
   base::RunLoop().RunUntilIdle();
 
-  EXPECT_EQ(1, cache.GetCountDoneHeadersQueue(kSimpleGET_Transaction.url));
+  EXPECT_EQ(2, cache.GetCountDoneHeadersQueue(kSimpleGET_Transaction.url));
   EXPECT_TRUE(cache.IsWriterPresent(kSimpleGET_Transaction.url));
 
   // Complete the rest of the transactions.
   for (int i = 2; i < kNumTransactions; ++i) {
     auto& c = context_list[i];
     ReadAndVerifyTransaction(c->trans.get(), kSimpleGET_Transaction);
   }
 
-  EXPECT_EQ(3, cache.network_layer()->transaction_count());
+  EXPECT_EQ(2, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
   EXPECT_EQ(2, cache.disk_cache()->create_count());
 }
 
 // Tests that a transaction is in validated queue and writer is destroyed
 // leading to restarting the validated transaction.
 TEST(HttpCache, SimpleGET_ParallelValidationCancelWriter) {
   MockHttpCache cache;
 
   MockHttpRequest request(kSimpleGET_Transaction);
@@ skipping 44 matching lines @@
 
   base::RunLoop().RunUntilIdle();
 
   EXPECT_TRUE(cache.IsWriterPresent(kSimpleGET_Transaction.url));
   EXPECT_TRUE(cache.IsHeadersTransactionPresent(kSimpleGET_Transaction.url));
 
   // Resume network start for the transaction the second time.
   c->trans->ResumeNetworkStart();
   base::RunLoop().RunUntilIdle();
 
-  // Headers transaction would have doomed the new entry created.
-  EXPECT_TRUE(
-      cache.disk_cache()->IsDiskEntryDoomed(kSimpleGET_Transaction.url));
-
   // Complete the rest of the transactions.
   for (auto& context : context_list) {
     if (!context)
       continue;
     ReadAndVerifyTransaction(context->trans.get(), kSimpleGET_Transaction);
   }
 
   EXPECT_EQ(4, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
-  EXPECT_EQ(2, cache.disk_cache()->create_count());
+  EXPECT_EQ(3, cache.disk_cache()->create_count());
 }
 
 // Tests when a writer is destroyed mid-read and entry is marked as truncated,
 // it should lead to restarting the dependent transactions.
 TEST(HttpCache, SimpleGET_ParallelValidationCancelWriterTruncateEntry) {
   MockHttpCache cache;
 
   ScopedMockTransaction transaction(kSimpleGET_Transaction);
   transaction.response_headers =
       "Last-Modified: Wed, 28 Nov 2007 00:40:09 GMT\n"
@@ skipping 108 matching lines @@
 
   base::RunLoop().RunUntilIdle();
 
   EXPECT_TRUE(cache.IsWriterPresent(kSimpleGET_Transaction.url));
   EXPECT_TRUE(cache.IsHeadersTransactionPresent(kSimpleGET_Transaction.url));
 
   // Resume network start for the transaction the second time.
   c->trans->ResumeNetworkStart();
   base::RunLoop().RunUntilIdle();
 
-  // Headers transaction would have doomed the new entry created.
-  EXPECT_TRUE(
-      cache.disk_cache()->IsDiskEntryDoomed(kSimpleGET_Transaction.url));
-
   // Complete the rest of the transactions.
   for (auto& context : context_list) {
     if (!context)
       continue;
     ReadAndVerifyTransaction(context->trans.get(), kSimpleGET_Transaction);
   }
 
   EXPECT_EQ(4, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
-  EXPECT_EQ(2, cache.disk_cache()->create_count());
+  EXPECT_EQ(3, cache.disk_cache()->create_count());
 }
 
 // Tests that a transaction is currently in headers phase and is destroyed
 // leading to destroying the entry.
 TEST(HttpCache, SimpleGET_ParallelValidationCancelHeaders) {
   MockHttpCache cache;
 
   MockHttpRequest request(kSimpleGET_Transaction);
 
   const int kNumTransactions = 2;
@@ skipping 273 matching lines @@
 
   // Allow all requests to move from the Create queue to the active entry.
   base::RunLoop().RunUntilIdle();
 
   // The first request should be a writer at this point, and the subsequent
   // requests should have completed validation. Since the validation does not
   // result in a match, a new entry would be created.
 
   EXPECT_EQ(3, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
-  EXPECT_EQ(2, cache.disk_cache()->create_count());
+  EXPECT_EQ(3, cache.disk_cache()->create_count());
 
   // Now, make sure that the second request asks for the entry not to be stored.
   request_handler.set_no_store(true);
 
   for (int i = 0; i < kNumTransactions; ++i) {
     Context* c = context_list[i].get();
     if (c->result == ERR_IO_PENDING)
       c->result = c->callback.WaitForResult();
     ReadAndVerifyTransaction(c->trans.get(), kFastNoStoreGET_Transaction);
     context_list[i].reset();
   }
 
   EXPECT_EQ(3, cache.network_layer()->transaction_count());
   EXPECT_EQ(0, cache.disk_cache()->open_count());
-  EXPECT_EQ(2, cache.disk_cache()->create_count());
+  EXPECT_EQ(3, cache.disk_cache()->create_count());
 
   RemoveMockTransaction(&kFastNoStoreGET_Transaction);
 }
 
 TEST(HttpCache, SimpleGET_ManyWriters_CancelFirst) {
   MockHttpCache cache;
 
   MockHttpRequest request(kSimpleGET_Transaction);
 
   std::vector<std::unique_ptr<Context>> context_list;
@@ skipping 1743 matching lines @@
   MockTransaction transaction(kSimpleGET_Transaction);
   AddMockTransaction(&transaction);
 
   // Populate the cache.
   RunTransactionTest(cache.http_cache(), transaction);
 
   // Load from cache.
   transaction.method = "HEAD";
   transaction.request_headers = "Range: bytes = 0-4\r\n";
   transaction.load_flags |= LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
-  transaction.return_code = ERR_CACHE_MISS;
+  transaction.start_return_code = ERR_CACHE_MISS;
   RunTransactionTest(cache.http_cache(), transaction);
 
   EXPECT_EQ(0, cache.disk_cache()->open_count());
   EXPECT_EQ(1, cache.disk_cache()->create_count());
   RemoveMockTransaction(&transaction);
 }
 
 // Tests that a HEAD request can be served from a partialy cached resource.
 TEST(HttpCache, SimpleHEAD_WithCachedRanges) {
   MockHttpCache cache;
@@ skipping 145 matching lines @@
 
   // Update the cache.
   transaction.method = "HEAD";
   transaction.data = "";
   RunTransactionTest(cache.http_cache(), transaction);
   EXPECT_EQ(2, cache.network_layer()->transaction_count());
 
   // Load from the cache.
   transaction.method = "GET";
   transaction.load_flags |= LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
-  transaction.return_code = ERR_CACHE_MISS;
+  transaction.start_return_code = ERR_CACHE_MISS;
   RunTransactionTest(cache.http_cache(), transaction);
 
   RemoveMockTransaction(&transaction);
 }
 
 // Tests that we do not cache the response of a PUT.
 TEST(HttpCache, SimplePUT_Miss) {
   MockHttpCache cache;
 
   MockTransaction transaction(kSimplePOST_Transaction);
@@ skipping 256 matching lines @@
 // Tests that we don't invalidate entries after a failed network transaction.
 TEST(HttpCache, SimpleGET_DontInvalidateOnFailure) {
   MockHttpCache cache;
 
   // Populate the cache.
   RunTransactionTest(cache.http_cache(), kSimpleGET_Transaction);
   EXPECT_EQ(1, cache.network_layer()->transaction_count());
 
   // Fail the network request.
   MockTransaction transaction(kSimpleGET_Transaction);
-  transaction.return_code = ERR_FAILED;
+  transaction.start_return_code = ERR_FAILED;
   transaction.load_flags |= LOAD_VALIDATE_CACHE;
 
   AddMockTransaction(&transaction);
   RunTransactionTest(cache.http_cache(), transaction);
   EXPECT_EQ(2, cache.network_layer()->transaction_count());
   RemoveMockTransaction(&transaction);
 
   transaction.load_flags = LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
-  transaction.return_code = OK;
+  transaction.start_return_code = OK;
   AddMockTransaction(&transaction);
   RunTransactionTest(cache.http_cache(), transaction);
 
   // Make sure the transaction didn't reach the network.
   EXPECT_EQ(2, cache.network_layer()->transaction_count());
   RemoveMockTransaction(&transaction);
 }
 
 TEST(HttpCache, RangeGET_SkipsCache) {
   MockHttpCache cache;
@@ skipping 3054 matching lines @@
   transaction.request_headers = "accept-encoding: gzip\r\n";
   transaction.response_headers =
       "Vary: accept-encoding\n"
       "Cache-Control: max-age=10000\n";
   RunTransactionTest(cache.http_cache(), transaction);
 
   // Change the request headers so that the request doesn't match due to vary.
   // The request should fail.
   transaction.load_flags = LOAD_ONLY_FROM_CACHE;
   transaction.request_headers = "accept-encoding: foo\r\n";
-  transaction.return_code = ERR_CACHE_MISS;
+  transaction.start_return_code = ERR_CACHE_MISS;
   RunTransactionTest(cache.http_cache(), transaction);
 
   // Change the load flags to ignore vary checks, the request should now hit.
   transaction.load_flags = LOAD_ONLY_FROM_CACHE | LOAD_SKIP_VARY_CHECK;
-  transaction.return_code = OK;
+  transaction.start_return_code = OK;
   RunTransactionTest(cache.http_cache(), transaction);
 }
 
 // Tests that we only return valid entries with LOAD_ONLY_FROM_CACHE
 // transactions unless LOAD_SKIP_CACHE_VALIDATION is set.
 TEST(HttpCache, ValidLoadOnlyFromCache) {
   MockHttpCache cache;
   base::SimpleTestClock* clock = new base::SimpleTestClock();
   cache.http_cache()->SetClockForTesting(base::WrapUnique(clock));
   cache.network_layer()->SetClock(clock);
 
   // Write a resource that will expire in 100 seconds.
   ScopedMockTransaction transaction(kSimpleGET_Transaction);
   transaction.response_headers = "Cache-Control: max-age=100\n";
   RunTransactionTest(cache.http_cache(), transaction);
 
   // Move forward in time such that the cached response is no longer valid.
   clock->Advance(base::TimeDelta::FromSeconds(101));
 
   // Skipping cache validation should still return a response.
   transaction.load_flags = LOAD_ONLY_FROM_CACHE | LOAD_SKIP_CACHE_VALIDATION;
   RunTransactionTest(cache.http_cache(), transaction);
 
   // If the cache entry is checked for validitiy, it should fail.
   transaction.load_flags = LOAD_ONLY_FROM_CACHE;
-  transaction.return_code = ERR_CACHE_MISS;
+  transaction.start_return_code = ERR_CACHE_MISS;
   RunTransactionTest(cache.http_cache(), transaction);
 }
 
 TEST(HttpCache, InvalidLoadFlagCombination) {
   MockHttpCache cache;
 
   // Put the resource in the cache.
   RunTransactionTest(cache.http_cache(), kSimpleGET_Transaction);
 
   // Now try to fetch it again, but with a flag combination disallowing both
   // cache and network access.
   ScopedMockTransaction transaction(kSimpleGET_Transaction);
   // DevTools relies on this combination of flags for "disable cache" mode
   // when a resource is only supposed to be loaded from cache.
   transaction.load_flags = LOAD_ONLY_FROM_CACHE | LOAD_BYPASS_CACHE;
-  transaction.return_code = ERR_CACHE_MISS;
+  transaction.start_return_code = ERR_CACHE_MISS;
   RunTransactionTest(cache.http_cache(), transaction);
 }
 
 // Tests that we can read metadata after validating the entry and with READ mode
 // transactions.
 TEST(HttpCache, ReadMetadata) {
   MockHttpCache cache;
 
   // Write to the cache
   HttpResponseInfo response;
@@ skipping 1258 matching lines @@
   ASSERT_TRUE(attrs->GetDictionary(
       base::trace_event::MemoryAllocatorDump::kNameSize, &size_attrs));
   std::string size;
   ASSERT_TRUE(size_attrs->GetString("value", &size));
   int actual_size = 0;
   ASSERT_TRUE(base::HexStringToInt(size, &actual_size));
   ASSERT_LT(0, actual_size);
 }
 
 }  // namespace net