Delete old files after an update.

chrome/installer/util/delete_old_versions.cc

Index: chrome/installer/util/delete_old_versions.cc
diff --git a/chrome/installer/util/delete_old_versions.cc b/chrome/installer/util/delete_old_versions.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ea3695b5fc4463706f168ac9e63af3eeb28f1c06
--- /dev/null
+++ b/chrome/installer/util/delete_old_versions.cc
@@ -0,0 +1,250 @@
+// 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 "chrome/installer/util/delete_old_versions.h"
+
+#include <map>
+#include <memory>
+#include <set>
+#include <vector>
+
+#include "base/file_version_info.h"
+#include "base/files/file.h"
+#include "base/files/file_enumerator.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/logging.h"
+#include "base/stl_util.h"
+#include "base/version.h"
+#include "chrome/installer/util/util_constants.h"
+
+namespace installer {
+
+namespace {
+
+using PathVector = std::vector<base::FilePath>;
+using DirectorySet = std::set<base::FilePath>;
+using ExecutableMap = std::map<base::FilePath, PathVector>;
+
+// Returns the name of the version directory for executable |exe_path|.
+base::FilePath GetExecutableVersionDirName(const base::FilePath& exe_path) {
+  std::unique_ptr<FileVersionInfo> file_version_info(
+      FileVersionInfo::CreateFileVersionInfo(exe_path));
+  if (!file_version_info.get())
+    return base::FilePath();
+  return base::FilePath(file_version_info->file_version());
+}
+
+// Returns the names of the old version directories found in |install_dir|. The
+// directories named after the version of chrome.exe or new_chrome.exe are
+// excluded.
+DirectorySet GetOldVersionDirectories(const base::FilePath& install_dir) {
+  const base::FilePath new_chrome_exe_version_dir_name =
+      GetExecutableVersionDirName(install_dir.Append(kChromeNewExe));
+  const base::FilePath chrome_exe_version_dir_name =
+      GetExecutableVersionDirName(install_dir.Append(kChromeExe));
+
+  DirectorySet directories;
+  base::FileEnumerator enum_directories(install_dir, false,
+                                        base::FileEnumerator::DIRECTORIES);
+  for (base::FilePath directory_path = enum_directories.Next();
+       !directory_path.empty(); directory_path = enum_directories.Next()) {
+    const base::FilePath directory_name = directory_path.BaseName();
+    const base::Version version(directory_name.AsUTF8Unsafe());
+    const size_t kNumChromeVersionComponents = 4;
+    if (version.IsValid() &&
+        version.components().size() == kNumChromeVersionComponents &&
+        directory_name != new_chrome_exe_version_dir_name &&
+        directory_name != chrome_exe_version_dir_name) {
+      directories.insert(directory_name);
+    }
+  }
+  return directories;
+}
+
+// Returns a map where the keys are version directory names and values are paths
+// of old_chrome*.exe executables found in |install_dir|.
+ExecutableMap GetOldExecutables(const base::FilePath& install_dir) {
+  ExecutableMap executables;
+  base::FileEnumerator enum_executables(install_dir, false,
+                                        base::FileEnumerator::FILES,
+                                        FILE_PATH_LITERAL("old_chrome*.exe"));
+  for (base::FilePath exe_path = enum_executables.Next(); !exe_path.empty();
+       exe_path = enum_executables.Next()) {
+    executables[GetExecutableVersionDirName(exe_path)].push_back(exe_path);
+  }
+  return executables;
+}
+
+// Deletes directories that are in |directories| and don't have a matching
+// executable in |executables|. Returns false if any such directories could not
+// be deleted.
+bool DeleteDirectoriesWithoutMatchingExecutable(
+    const DirectorySet& directories,
+    const ExecutableMap& executables,
+    const base::FilePath& install_dir) {
+  bool success = true;
+  for (const base::FilePath& directory_name : directories) {
+    // Delete the directory if it doesn't have a matching executable.
+    if (!base::ContainsKey(executables, directory_name)) {
+      const base::FilePath directory_path = install_dir.Append(directory_name);
+      LOG(WARNING) << "Attempting to delete stray directory "
+                   << directory_path.value();
+      if (!base::DeleteFile(directory_path, true)) {
+        PLOG(ERROR) << "Failed to delete stray directory "
+                    << directory_path.value();
+        success = false;
+      }
+    }
+  }
+  return success;
+}
+
+// Deletes executables that are in |executables| and don't have a matching
+// directory in |directories|. Returns false if any such files could not be
+// deleted.
+bool DeleteExecutablesWithoutMatchingDirectory(
+    const DirectorySet& directories,
+    const ExecutableMap& executables) {
+  bool success = true;
+  for (const auto& version_and_executables : executables) {
+    const auto& version_dir_name = version_and_executables.first;
+    const auto& executables_for_version = version_and_executables.second;
+
+    // Don't delete the executables if they have a matching directory.
+    if (base::ContainsValue(directories, version_dir_name))
+      continue;
+
+    // Delete executables for version |version_dir_name|.
+    for (const auto& executable_path : executables_for_version) {
+      const base::FilePath executable_name = executable_path.BaseName();
+      LOG(WARNING) << "Attempting to delete stray executable "
+                   << executable_path.value();
+      if (!base::DeleteFile(executable_path, false)) {
+        PLOG(ERROR) << "Failed to delete stray executable "
+                    << executable_path.value();
+        success = false;
+      }
+    }
+  }
+  return success;
+}
+
+// Opens |path| with options that prevent the file from being read or written
+// via another handle. As long as the returned object is alive, it is guaranteed
+// that |path| isn't in use. It can however be deleted.
+base::File GetFileLock(const base::FilePath& path) {
+  return base::File(path, base::File::FLAG_OPEN | base::File::FLAG_READ |
+                              base::File::FLAG_EXCLUSIVE_READ |
+                              base::File::FLAG_EXCLUSIVE_WRITE |
+                              base::File::FLAG_SHARE_DELETE);
+}
+
+// Deletes |version_directory| and all executables in |version_executables| if
+// no .exe or .dll file for the version is in use. Returns false if any file
+// or directory for the version could not be deleted.
+bool DeleteVersion(const base::FilePath& version_directory,
+                   const PathVector& version_executables) {
+  std::vector<base::File> locks;
+  PathVector locked_file_paths;
+
+  // Lock .exe/.dll files in |version_directory|.
+  base::FileEnumerator enum_version_directory(version_directory, true,
+                                              base::FileEnumerator::FILES);
+  for (base::FilePath path = enum_version_directory.Next(); !path.empty();
+       path = enum_version_directory.Next()) {
+    if (!path.MatchesExtension(FILE_PATH_LITERAL(".exe")) &&
+        !path.MatchesExtension(FILE_PATH_LITERAL(".dll"))) {
+      continue;
+    }
+    locks.push_back(GetFileLock(path));
+    if (!locks.back().IsValid()) {
+      LOG(WARNING) << "Failed to delete old version "
+                   << version_directory.value() << " because " << path.value()
+                   << " is in use.";
+      return false;
+    }
+    locked_file_paths.push_back(path);
+  }
+
+  // Lock executables in |version_executables|.
+  for (const base::FilePath& executable_path : version_executables) {
+    locks.push_back(GetFileLock(executable_path));
+    if (!locks.back().IsValid()) {
+      LOG(WARNING) << "Failed to delete old version "
+                   << version_directory.value() << " because "
+                   << executable_path.value() << " is in use.";
+      return false;
+    }
+    locked_file_paths.push_back(executable_path);
+  }
+
+  bool success = true;
+
+  // Delete locked files. The files won't actually be deleted until the locks
+  // are released.
+  for (const base::FilePath& locked_file_path : locked_file_paths) {
+    if (!base::DeleteFile(locked_file_path, false)) {
+      PLOG(ERROR) << "Failed to delete locked file "
+                  << locked_file_path.value();
+      success = false;
+    }
+  }
+
+  // Release the locks, causing the locked files to actually be deleted. The
+  // version directory can't be deleted before this is done.
+  locks.clear();
+
+  // Delete the version directory.
+  if (!base::DeleteFile(version_directory, true)) {
+    PLOG(ERROR) << "Failed to delete version directory "
+                << version_directory.value();
+    success = false;
+  }
+
+  return success;
+}
+
+// For each executable in |executables| that has a matching directory in
+// |directories|, tries to delete the executable and the matching directory. No
+// deletion occurs for a given version if a .exe or .dll file for that version
+// is in use. Returns false if any directory/executables pair could not be
+// deleted.
+bool DeleteMatchingExecutablesAndDirectories(
+    const DirectorySet& directories,
+    const ExecutableMap& executables,
+    const base::FilePath& install_dir) {
+  bool success = true;
+  for (const auto& directory_name : directories) {
+    // Don't delete the version unless the directory has at least one matching
+    // executable.
+    auto version_executables_it = executables.find(directory_name);
+    if (version_executables_it == executables.end())
+      continue;
+
+    // Try to delete all files for the version.
+    success &= DeleteVersion(install_dir.Append(directory_name),
+                             version_executables_it->second);
+  }
+  return success;
+}
+
+}  // namespace
+
+bool DeleteOldVersions(const base::FilePath& install_dir) {
+  const DirectorySet old_directories = GetOldVersionDirectories(install_dir);
+  const ExecutableMap old_executables = GetOldExecutables(install_dir);
+
+  bool success = true;
+  success &= DeleteDirectoriesWithoutMatchingExecutable(
+      old_directories, old_executables, install_dir);
+  success &= DeleteExecutablesWithoutMatchingDirectory(old_directories,
+                                                       old_executables);
+  success &= DeleteMatchingExecutablesAndDirectories(
+      old_directories, old_executables, install_dir);
+
+  return success;
+}
+
+}  // namespace installer