Implements cachetool to manipulate simple typed cache.

net/tools/cachetool/cachetool.cc

Index: net/tools/cachetool/cachetool.cc
diff --git a/net/tools/cachetool/cachetool.cc b/net/tools/cachetool/cachetool.cc
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+// 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 <iostream>
+
+#include "base/at_exit.h"
+#include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/string_number_conversions.h"
+#include "net/base/io_buffer.h"
+#include "net/base/test_completion_callback.h"
+#include "net/disk_cache/disk_cache.h"
+#include "net/disk_cache/simple/simple_backend_impl.h"
+#include "net/http/http_cache.h"
+#include "net/http/http_response_headers.h"
+#include "net/http/http_util.h"
+
+using disk_cache::Backend;
+using disk_cache::Entry;
+using disk_cache::SimpleBackendImpl;
+
+namespace {
+
+base::MessageLoopForIO* g_message_loop = nullptr;
+
+scoped_ptr<SimpleBackendImpl> CreateSimpleBackend(
+    const base::FilePath& cache_path) {
+  scoped_ptr<SimpleBackendImpl> cache_backend(new SimpleBackendImpl(
+      cache_path, 0, net::DISK_CACHE, g_message_loop->task_runner(), NULL));
+
+  net::TestCompletionCallback cb;
+  int rv = cache_backend->Init(cb.callback());
+  if (cb.GetResult(rv) != net::OK)
+    return nullptr;
+  return cache_backend;
+}
+
+// Print all of a cache's keys to stdout.
+bool ListKeys(Backend* cache_backend) {
+  scoped_ptr<Backend::Iterator> entry_iterator =
+      cache_backend->CreateIterator();
+  Entry* entry = nullptr;
+  net::TestCompletionCallback cb;
+  int rv = entry_iterator->OpenNextEntry(&entry, cb.callback());
+  while (cb.GetResult(rv) == net::OK) {
+    std::string url = entry->GetKey();
+    std::cout << url << std::endl;
+    entry->Close();
+    entry = nullptr;
+    rv = entry_iterator->OpenNextEntry(&entry, cb.callback());
+  }
+  return true;
+}
+
+// Print a key's stream to stdout.
+bool GetKeyStream(Backend* cache_backend, const std::string& key, int index) {
+  if (index < 0 || index > 2) {
+    std::cerr << "Invalid stream index." << std::endl;
+    return false;
+  }
+
+  Entry* cache_entry;
+  net::TestCompletionCallback cb;
+  int rv = cache_backend->OpenEntry(key, &cache_entry, cb.callback());
+  if (cb.GetResult(rv) != net::OK) {
+    std::cerr << "Couldn't find key's entry." << std::endl;
+    return false;
+  }
+
+  const int kInitBufferSize = 8192;
+  scoped_refptr<net::GrowableIOBuffer> buffer(new net::GrowableIOBuffer());
+  buffer->SetCapacity(kInitBufferSize);
+  for (;;) {

[gavinp, 2016/02/23 15:38:15]

Nit: I very slightly prefer "while (true)" here, but I can't find justification
in our coding style to actually make more than a nit here.

[gabadie, 2016/02/23 15:43:51]

Done.

+    rv = cache_entry->ReadData(index, buffer->offset(), buffer.get(),
+                               buffer->capacity() - buffer->offset(),
+                               cb.callback());
+    rv = cb.GetResult(rv);
+    if (rv < 0) {
+      cache_entry->Close();
+      std::cerr << "Stream read error." << std::endl;
+      return false;
+    }
+    buffer->set_offset(buffer->offset() + rv);
+    if (rv == 0) {

[gavinp, 2016/02/23 15:38:15]

Nit: you could lose these braces.

[gabadie, 2016/02/23 15:43:51]

Done.

+      break;
+    }
+    buffer->SetCapacity(buffer->offset() * 2);
+  }
+  cache_entry->Close();
+  if (index == 0) {
+    net::HttpResponseInfo response_info;
+    bool truncated_response_info = false;
+    net::HttpCache::ParseResponseInfo(buffer->StartOfBuffer(), buffer->offset(),
+                                      &response_info, &truncated_response_info);
+    if (truncated_response_info) {
+      std::cerr << "Truncated HTTP response." << std::endl;
+      return false;
+    }
+    std::cout << net::HttpUtil::ConvertHeadersBackToHTTPResponse(
+        response_info.headers->raw_headers());
+  } else {
+    std::cout.write(buffer->StartOfBuffer(), buffer->offset());
+  }
+  return true;
+}
+
+// Delete a specified key from the cache.
+bool DeleteKey(Backend* cache_backend, const std::string& key) {
+  net::TestCompletionCallback cb;
+  int rv = cache_backend->DoomEntry(key, cb.callback());
+  if (cb.GetResult(rv) != net::OK) {
+    std::cerr << "Couldn't delete key." << std::endl;
+    return false;
+  }
+  return true;
+}
+
+// Print the command line help.
+void PrintHelp() {
+  std::cout << "cachetool <cache_path> <cache_backend_type> <subcommand> ..."
+            << std::endl
+            << std::endl;
+  std::cout << "Available cache back-end types: simple";
+  std::cout << "Available subcommands:" << std::endl;
+  std::cout << "  validate: Verify that the cache can be opened and return, "
+            << "confirming the cache exists and is of the right type."
+            << std::endl;
+  std::cout << "  list_keys: List all keys in cache." << std::endl;

[gavinp, 2016/02/23 15:38:15]

Nit: "a cache" or "the cache"

(yes, I'm telling you to add an article)

[gabadie, 2016/02/23 15:43:51]

Done.

+  std::cout << "  get_stream <key> <index>: Print a particular stream for a"
+            << " given key." << std::endl;
+  std::cout << "  delete_key <key>: Delete key from cache." << std::endl;
+  std::cout << "Expected values of <index> are:" << std::endl;
+  std::cout << "  0 (HTTP response header)" << std::endl;

[gavinp, 2016/02/23 15:38:15]

nit: headers

[gabadie, 2016/02/23 15:43:51]

Done.

+  std::cout << "  1 (transport encoded content)" << std::endl;
+  std::cout << "  2 (compiled content)" << std::endl;
+}
+
+}  // namespace
+
+int main(int argc, char* argv[]) {
+  base::AtExitManager at_exit_manager;
+  base::MessageLoopForIO message_loop;
+  base::CommandLine::Init(argc, argv);
+  const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+
+  base::CommandLine::StringVector args = command_line.GetArgs();
+  if (args.size() < 3U) {
+    PrintHelp();
+    return 1;
+  }
+
+  base::FilePath cache_path(args[0]);
+  std::string cache_backend_type(args[1]);
+  std::string subcommand(args[2]);
+
+  g_message_loop = &message_loop;
+  scoped_ptr<Backend> cache_backend;
+  if (cache_backend_type == "simple") {
+    cache_backend = CreateSimpleBackend(cache_path);
+  } else {
+    std::cerr << "Unknown cache type." << std::endl;
+    PrintHelp();
+    return 1;
+  }
+
+  if (!cache_backend) {
+    std::cerr << "Invalid cache." << std::endl;
+    PrintHelp();
+    return 1;
+  }
+
+  bool successful_command = false;
+  if (subcommand == "validate") {
+    if (args.size() != 3) {
+      PrintHelp();
+      return 1;
+    }
+    successful_command = true;
+  } else if (subcommand == "list_keys") {
+    if (args.size() != 3) {
+      PrintHelp();
+      return 1;
+    }
+    successful_command = ListKeys(cache_backend.get());
+  } else if (subcommand == "get_stream") {
+    if (args.size() != 5) {
+      PrintHelp();
+      return 1;
+    }
+    std::string key(args[3]);
+    int index = 0;
+    if (!base::StringToInt(args[4], &index)) {
+      std::cerr << "<index> must be an integer." << std::endl;
+      PrintHelp();
+      return 1;
+    }
+    successful_command = GetKeyStream(cache_backend.get(), key, index);
+  } else if (subcommand == "delete_key") {
+    if (args.size() != 4) {
+      PrintHelp();
+      return 1;
+    }
+    std::string key(args[3]);
+    successful_command = DeleteKey(cache_backend.get(), key);
+  } else {
+    std::cerr << "Unknown subcommand." << std::endl;
+    PrintHelp();
+  }
+  return successful_command ? 0 : 1;

[gavinp, 2016/02/23 15:38:14]

Nit: you could return !successful_command here.

[gabadie, 2016/02/23 15:43:51]

Done.

+}