Disk cache: Add a tool to upgrade a set of cache files from one version to...

net/tools/dump_cache/dump_cache.cc

+// Copyright (c) 2008 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.
+
+// This command-line program dumps the contents of a set of cache files, either
+// to stdout or to another set of cache files.
+
+#include <stdio.h>
+#include <string>
+
+#include "base/at_exit.h"
+#include "base/command_line.h"
+#include "base/process_util.h"
+#include "base/scoped_handle.h"
+#include "base/string_util.h"
+
+#include "net/disk_cache/disk_format.h"
+
+enum Errors {
+  GENERIC = -1,
+  ALL_GOOD = 0,
+  INVALID_ARGUMENT = 1,
+  FILE_ACCESS_ERROR,
+  UNKNOWN_VERSION,
+  TOOL_NOT_FOUND,
+};
+
+int GetMajorVersion(const std::wstring input_path);
+int DumpContents(const std::wstring input_path);
+int DumpHeaders(const std::wstring input_path);
+int RunSlave(const std::wstring input_path, const std::wstring pipe_number);
+int Upgrade(const std::wstring output_path, HANDLE pipe);
+HANDLE CreateServer(std::wstring* pipe_number);
+
+const char kUpgradeHelp[] =
+    "\nIn order to use the upgrade function, a version of this tool that\n"
+    "understands the file format of the files to upgrade is needed. For\n"
+    "instance, to upgrade files saved with file format 3.4 to version 5.2,\n"
+    "a version of this program that was compiled with version 3.4 has to be\n"
+    "located beside this executable, and named dump_cache_3.exe, and this\n"
+    "executable should be compiled with version 5.2 being the current one.";
+
+// Folders to read and write cache files.
+const wchar_t kInputPath[] = L"input";
+const wchar_t kOutputPath[] = L"output";
+
+// Dumps the file headers to stdout.
+const wchar_t kDumpHeaders[] = L"dump-headers";
+
+// Dumps all entries to stdout.
+const wchar_t kDumpContents[] = L"dump-contents";
+
+// Upgrade an old version to the current one.
+const wchar_t kUpgrade[] = L"upgrade";
+
+// Internal use:
+const wchar_t kSlave[] = L"slave";
+const wchar_t kPipe[] = L"pipe";
+
+int Help() {
+  printf("warning: input files are modified by this tool\n");
+  printf("dump_cache --input=path1 [--output=path2]\n");
+  printf("--dump-headers: display file headers\n");
+  printf("--dump-contents: display all entries\n");
+  printf("--upgrade: copy contents to the output path\n");
+  return INVALID_ARGUMENT;
+}
+
+// Starts a new process, to generate the files.
+int LaunchSlave(CommandLine &command_line, const std::wstring pipe_number,
+                int version) {
+  std::wstring new_command_line = command_line.command_line_string();
+  const std::wstring old_exe(L"dump_cache.exe");
+  size_t to_remove = new_command_line.find(old_exe);
+  new_command_line.erase(to_remove, old_exe.size());
+
+  std::wstring new_program = StringPrintf(L"%ls%d.exe", L"dump_cache_",
+                                          version);
+  new_command_line.insert(to_remove, new_program);
+  if (command_line.HasSwitch(kUpgrade))
+    CommandLine::AppendSwitch(&new_command_line, kSlave);
+
+  CommandLine::AppendSwitchWithValue(&new_command_line, kPipe, pipe_number);
+  if (!base::LaunchApp(new_command_line, false, false, NULL)) {
+    printf("Unable to launch the needed version of this tool: %ls\n",
+           new_program.c_str());
+    printf(kUpgradeHelp);
+    return TOOL_NOT_FOUND;
+  }
+  return ALL_GOOD;
+}
+
+// -----------------------------------------------------------------------
+
+int main(int argc, const char* argv[]) {
+  // Setup an AtExitManager so Singleton objects will be destroyed.
+  base::AtExitManager at_exit_manager;
+
+  CommandLine command_line;
+  std::wstring input_path = command_line.GetSwitchValue(kInputPath);
+  if (input_path.empty())
+    return Help();
+
+  bool upgrade = false;
+  bool slave_required = false;
+  std::wstring output_path;
+  if (command_line.HasSwitch(kUpgrade)) {
+    output_path = command_line.GetSwitchValue(kOutputPath);
+    if (output_path.empty())
+      return Help();
+    slave_required = true;
+    upgrade = true;
+  }
+
+  int version = GetMajorVersion(input_path);
+  if (!version)
+    return FILE_ACCESS_ERROR;
+
+  if (version != disk_cache::kCurrentVersion >> 16) {
+    if (command_line.HasSwitch(kSlave)) {
+      printf("Unknown version\n");
+      return UNKNOWN_VERSION;
+    }
+    slave_required = true;        
+  }
+
+  std::wstring pipe_number = command_line.GetSwitchValue(kPipe);
+  if (command_line.HasSwitch(kSlave) && slave_required)
+    return RunSlave(input_path, pipe_number);
+
+  ScopedHandle server;
+  if (slave_required) {
+    server.Set(CreateServer(&pipe_number));
+    if (!server.IsValid()) {
+      printf("Unable to create the server pipe\n");
+      return -1;
+    }
+
+    int ret = LaunchSlave(command_line, pipe_number, version);
+    if (ret)
+      return ret;
+  }
+
+  if (upgrade)
+    return Upgrade(output_path, server);
+
+  if (slave_required) {
+    // Wait until the slave starts dumping data before we quit. Lazy "fix" for a
+    // console quirk.
+    Sleep(500);
+    return ALL_GOOD;
+  }
+
+  if (command_line.HasSwitch(kDumpContents))
+    return DumpContents(input_path);
+  if (command_line.HasSwitch(kDumpHeaders))
+    return DumpHeaders(input_path);
+  return Help();
+}
+