| // 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 "base/path_service.h" |
| |
| #include <unordered_map> |
| |
| #if defined(OS_WIN) |
| #include <windows.h> |
| #include <shellapi.h> |
| #include <shlobj.h> |
| #endif |
| |
| #include "base/files/file_path.h" |
| #include "base/files/file_util.h" |
| #include "base/logging.h" |
| #include "base/synchronization/lock.h" |
| #include "build/build_config.h" |
| |
| namespace base { |
| |
| bool PathProvider(int key, FilePath* result); |
| |
| #if defined(OS_WIN) |
| bool PathProviderWin(int key, FilePath* result); |
| #elif defined(OS_MACOSX) |
| bool PathProviderMac(int key, FilePath* result); |
| #elif defined(OS_ANDROID) |
| bool PathProviderAndroid(int key, FilePath* result); |
| #elif defined(OS_FUCHSIA) |
| bool PathProviderFuchsia(int key, FilePath* result); |
| #elif defined(OS_POSIX) |
| // PathProviderPosix is the default path provider on POSIX OSes other than |
| // Mac and Android. |
| bool PathProviderPosix(int key, FilePath* result); |
| #endif |
| |
| namespace { |
| |
| typedef std::unordered_map<int, FilePath> PathMap; |
| |
| // We keep a linked list of providers. In a debug build we ensure that no two |
| // providers claim overlapping keys. |
| struct Provider { |
| PathService::ProviderFunc func; |
| struct Provider* next; |
| #ifndef NDEBUG |
| int key_start; |
| int key_end; |
| #endif |
| bool is_static; |
| }; |
| |
| Provider base_provider = {PathProvider, nullptr, |
| #ifndef NDEBUG |
| PATH_START, PATH_END, |
| #endif |
| true}; |
| |
| #if defined(OS_WIN) |
| Provider base_provider_win = { |
| PathProviderWin, |
| &base_provider, |
| #ifndef NDEBUG |
| PATH_WIN_START, |
| PATH_WIN_END, |
| #endif |
| true |
| }; |
| #endif |
| |
| #if defined(OS_MACOSX) |
| Provider base_provider_mac = { |
| PathProviderMac, |
| &base_provider, |
| #ifndef NDEBUG |
| PATH_MAC_START, |
| PATH_MAC_END, |
| #endif |
| true |
| }; |
| #endif |
| |
| #if defined(OS_ANDROID) |
| Provider base_provider_android = { |
| PathProviderAndroid, |
| &base_provider, |
| #ifndef NDEBUG |
| PATH_ANDROID_START, |
| PATH_ANDROID_END, |
| #endif |
| true |
| }; |
| #endif |
| |
| #if defined(OS_FUCHSIA) |
| Provider base_provider_fuchsia = {PathProviderFuchsia, &base_provider, |
| #ifndef NDEBUG |
| 0, 0, |
| #endif |
| true}; |
| #endif |
| |
| #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID) && \ |
| !defined(OS_FUCHSIA) |
| Provider base_provider_posix = { |
| PathProviderPosix, |
| &base_provider, |
| #ifndef NDEBUG |
| PATH_POSIX_START, |
| PATH_POSIX_END, |
| #endif |
| true |
| }; |
| #endif |
| |
| |
| struct PathData { |
| Lock lock; |
| PathMap cache; // Cache mappings from path key to path value. |
| PathMap overrides; // Track path overrides. |
| Provider* providers; // Linked list of path service providers. |
| bool cache_disabled; // Don't use cache if true; |
| |
| PathData() : cache_disabled(false) { |
| #if defined(OS_WIN) |
| providers = &base_provider_win; |
| #elif defined(OS_MACOSX) |
| providers = &base_provider_mac; |
| #elif defined(OS_ANDROID) |
| providers = &base_provider_android; |
| #elif defined(OS_FUCHSIA) |
| providers = &base_provider_fuchsia; |
| #elif defined(OS_POSIX) |
| providers = &base_provider_posix; |
| #endif |
| } |
| }; |
| |
| static PathData* GetPathData() { |
| static auto* path_data = new PathData(); |
| return path_data; |
| } |
| |
| // Tries to find |key| in the cache. |path_data| should be locked by the caller! |
| bool LockedGetFromCache(int key, const PathData* path_data, FilePath* result) { |
| if (path_data->cache_disabled) |
| return false; |
| // check for a cached version |
| auto it = path_data->cache.find(key); |
| if (it != path_data->cache.end()) { |
| *result = it->second; |
| return true; |
| } |
| return false; |
| } |
| |
| // Tries to find |key| in the overrides map. |path_data| should be locked by the |
| // caller! |
| bool LockedGetFromOverrides(int key, PathData* path_data, FilePath* result) { |
| // check for an overridden version. |
| PathMap::const_iterator it = path_data->overrides.find(key); |
| if (it != path_data->overrides.end()) { |
| if (!path_data->cache_disabled) |
| path_data->cache[key] = it->second; |
| *result = it->second; |
| return true; |
| } |
| return false; |
| } |
| |
| } // namespace |
| |
| // TODO(brettw): this function does not handle long paths (filename > MAX_PATH) |
| // characters). This isn't supported very well by Windows right now, so it is |
| // moot, but we should keep this in mind for the future. |
| // static |
| bool PathService::Get(int key, FilePath* result) { |
| PathData* path_data = GetPathData(); |
| DCHECK(path_data); |
| DCHECK(result); |
| DCHECK_GE(key, DIR_CURRENT); |
| |
| // special case the current directory because it can never be cached |
| if (key == DIR_CURRENT) |
| return GetCurrentDirectory(result); |
| |
| Provider* provider = nullptr; |
| { |
| AutoLock scoped_lock(path_data->lock); |
| if (LockedGetFromCache(key, path_data, result)) |
| return true; |
| |
| if (LockedGetFromOverrides(key, path_data, result)) |
| return true; |
| |
| // Get the beginning of the list while it is still locked. |
| provider = path_data->providers; |
| } |
| |
| FilePath path; |
| |
| // Iterating does not need the lock because only the list head might be |
| // modified on another thread. |
| while (provider) { |
| if (provider->func(key, &path)) |
| break; |
| DCHECK(path.empty()) << "provider should not have modified path"; |
| provider = provider->next; |
| } |
| |
| if (path.empty()) |
| return false; |
| |
| if (path.ReferencesParent()) { |
| // Make sure path service never returns a path with ".." in it. |
| path = MakeAbsoluteFilePath(path); |
| if (path.empty()) |
| return false; |
| } |
| *result = path; |
| |
| AutoLock scoped_lock(path_data->lock); |
| if (!path_data->cache_disabled) |
| path_data->cache[key] = path; |
| |
| return true; |
| } |
| |
| // static |
| bool PathService::Override(int key, const FilePath& path) { |
| // Just call the full function with true for the value of |create|, and |
| // assume that |path| may not be absolute yet. |
| return OverrideAndCreateIfNeeded(key, path, false, true); |
| } |
| |
| // static |
| bool PathService::OverrideAndCreateIfNeeded(int key, |
| const FilePath& path, |
| bool is_absolute, |
| bool create) { |
| PathData* path_data = GetPathData(); |
| DCHECK(path_data); |
| DCHECK_GT(key, DIR_CURRENT) << "invalid path key"; |
| |
| FilePath file_path = path; |
| |
| // For some locations this will fail if called from inside the sandbox there- |
| // fore we protect this call with a flag. |
| if (create) { |
| // Make sure the directory exists. We need to do this before we translate |
| // this to the absolute path because on POSIX, MakeAbsoluteFilePath fails |
| // if called on a non-existent path. |
| if (!PathExists(file_path) && !CreateDirectory(file_path)) |
| return false; |
| } |
| |
| // We need to have an absolute path. |
| if (!is_absolute) { |
| file_path = MakeAbsoluteFilePath(file_path); |
| if (file_path.empty()) |
| return false; |
| } |
| DCHECK(file_path.IsAbsolute()); |
| |
| AutoLock scoped_lock(path_data->lock); |
| |
| // Clear the cache now. Some of its entries could have depended |
| // on the value we are overriding, and are now out of sync with reality. |
| path_data->cache.clear(); |
| |
| path_data->overrides[key] = file_path; |
| |
| return true; |
| } |
| |
| // static |
| bool PathService::RemoveOverride(int key) { |
| PathData* path_data = GetPathData(); |
| DCHECK(path_data); |
| |
| AutoLock scoped_lock(path_data->lock); |
| |
| if (path_data->overrides.find(key) == path_data->overrides.end()) |
| return false; |
| |
| // Clear the cache now. Some of its entries could have depended on the value |
| // we are going to remove, and are now out of sync. |
| path_data->cache.clear(); |
| |
| path_data->overrides.erase(key); |
| |
| return true; |
| } |
| |
| // static |
| void PathService::RegisterProvider(ProviderFunc func, int key_start, |
| int key_end) { |
| PathData* path_data = GetPathData(); |
| DCHECK(path_data); |
| DCHECK_GT(key_end, key_start); |
| |
| Provider* p; |
| |
| p = new Provider; |
| p->is_static = false; |
| p->func = func; |
| #ifndef NDEBUG |
| p->key_start = key_start; |
| p->key_end = key_end; |
| #endif |
| |
| AutoLock scoped_lock(path_data->lock); |
| |
| #ifndef NDEBUG |
| Provider *iter = path_data->providers; |
| while (iter) { |
| DCHECK(key_start >= iter->key_end || key_end <= iter->key_start) << |
| "path provider collision"; |
| iter = iter->next; |
| } |
| #endif |
| |
| p->next = path_data->providers; |
| path_data->providers = p; |
| } |
| |
| // static |
| void PathService::DisableCache() { |
| PathData* path_data = GetPathData(); |
| DCHECK(path_data); |
| |
| AutoLock scoped_lock(path_data->lock); |
| path_data->cache.clear(); |
| path_data->cache_disabled = true; |
| } |
| |
| } // namespace base |