gdata: Support mounting archive files in GData cache.

chrome/browser/chromeos/gdata/gdata_file_system.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 "chrome/browser/chromeos/gdata/gdata_file_system.h"
 
 #include <errno.h>
 #include <sys/stat.h>
 
 #include <set>
@@ skipping 36 matching lines @@
 namespace gdata {
 namespace {
 
 const char kMimeTypeJson[] = "application/json";
 const char kMimeTypeOctetStream[] = "application/octet-stream";
 
 const FilePath::CharType kGDataRootDirectory[] = FILE_PATH_LITERAL("gdata");
 const char kFeedField[] = "feed";
 const char kWildCard[] = "*";
 const char kLocallyModifiedFileExtension[] = "local";
+const char kMountedArchiveFileExtension[] = "mounted";
 
 const FilePath::CharType kGDataCacheVersionDir[] = FILE_PATH_LITERAL("v1");
 const FilePath::CharType kGDataCacheMetaDir[] = FILE_PATH_LITERAL("meta");
 const FilePath::CharType kGDataCachePinnedDir[] = FILE_PATH_LITERAL("pinned");
 const FilePath::CharType kGDataCacheOutgoingDir[] =
     FILE_PATH_LITERAL("outgoing");
 const FilePath::CharType kGDataCachePersistentDir[] =
     FILE_PATH_LITERAL("persistent");
 const FilePath::CharType kGDataCacheTmpDir[] = FILE_PATH_LITERAL("tmp");
 const FilePath::CharType kGDataCacheTmpDownloadsDir[] =
@@ skipping 370 matching lines @@
     const std::string& md5,
     const FilePath& gdata_file_path,
     FilePath* cache_file_path) {
   DCHECK(error);
   DCHECK(cache_file_path);
 
   if (!callback.is_null())
     callback.Run(*error, resource_id, md5, gdata_file_path, *cache_file_path);
 }
 
+// Ditto for SetMountedStateCallback
+void RunSetMountedStateCallbackHelper(
+    const SetMountedStateCallback& callback,
+    base::PlatformFileError* error,
+    FilePath* cache_file_path) {
+  DCHECK(error);
+  DCHECK(cache_file_path);
+
+  if (!callback.is_null())
+    callback.Run(*error, *cache_file_path);
+}
+
 void RunGetCacheStateCallbackHelper(
     const GetCacheStateCallback& callback,
     base::PlatformFileError* error,
     int* cache_state) {
   DCHECK(error);
   DCHECK(cache_state);
 
   if (!callback.is_null())
     callback.Run(*error, *cache_state);
 }
@@ skipping 1401 matching lines @@
   if (regular_file) {
     properties->file_md5 = regular_file->file_md5();
     properties->mime_type = regular_file->content_mime_type();
     properties->content_url = regular_file->content_url();
     properties->alternate_url = regular_file->alternate_url();
     properties->is_hosted_document = regular_file->is_hosted_document();
   }
   return true;
 }
 
+bool GDataFileSystem::IsUnderGDataCacheDirectory(const FilePath& path) const {
+  return gdata_cache_path_ == path || gdata_cache_path_.IsParent(path);
+}
+
 FilePath GDataFileSystem::GetGDataCacheTmpDirectory() const {
   return cache_paths_[GDataRootDirectory::CACHE_TYPE_TMP];
 }
 
 FilePath GDataFileSystem::GetGDataTempDownloadFolderPath() const {
   return cache_paths_[GDataRootDirectory::CACHE_TYPE_TMP_DOWNLOADS];
 }
 
 FilePath GDataFileSystem::GetGDataTempDocumentFolderPath() const {
   return cache_paths_[GDataRootDirectory::CACHE_TYPE_TMP_DOCUMENTS];
@@ skipping 128 matching lines @@
                                 GetWeakPtrForCurrentThread(),
                                 callback);
   }
 
   if (to_pin)
     Pin(resource_id, md5, cache_callback);
   else
     Unpin(resource_id, md5, cache_callback);
 }
 
+void GDataFileSystem::SetMountedState(const FilePath& file_path, bool to_mount,
+                                      const SetMountedStateCallback& callback) {
+  InitializeCacheIfNecessary();
+
+  base::PlatformFileError* error =
+      new base::PlatformFileError(base::PLATFORM_FILE_OK);
+  FilePath* cache_file_path = new FilePath;
+  PostBlockingPoolSequencedTaskAndReply(
+      kGDataFileSystemToken,
+      FROM_HERE,
+      base::Bind(&GDataFileSystem::SetMountedStateOnIOThreadPool,

[satorux1, 2012/04/18 23:29:04]

It's sad to see a new non-static member function runs on the thread pool. I'm
planning to get rid of all of them. However, there doesn't seem to be an easy
way to avoid doing this, so I'm fine with that at this moment...

+                 base::Unretained(this),
+                 file_path,
+                 to_mount,
+                 error,
+                 cache_file_path),
+      base::Bind(&RunSetMountedStateCallbackHelper,
+                 callback,
+                 base::Owned(error),
+                 base::Owned(cache_file_path)));
+}
+
+void GDataFileSystem::SetMountedStateOnIOThreadPool(
+    const FilePath& file_path,
+    bool to_mount,
+    base::PlatformFileError *error,
+    FilePath* cache_file_path) {
+  DCHECK(error);
+  DCHECK(cache_file_path);
+
+  // Lock to access cache map.
+  base::AutoLock lock(lock_);
+
+  FilePath base_name = file_path.BaseName();
+  FilePath::StringType resource_id = base_name.RemoveExtension().value();
+  FilePath::StringType extension = base_name.Extension();
+  FilePath::StringType md5 = FilePath::StringType();
+  if (to_mount && !extension.empty()) {
+    // FilePath::Extension returns ".", so strip it.
+    md5 = GDataFileBase::UnescapeUtf8FileName(extension.substr(1));
+  }
+  GDataRootDirectory::CacheEntry* entry = root_->GetCacheEntry(resource_id,
+                                                               md5);
+  if (!entry) {
+    *error = base::PLATFORM_FILE_ERROR_NOT_FOUND;
+    return;
+  }
+  if ((to_mount && entry->IsMounted()) ||

[tbarzic, 2012/04/18 23:43:14]

if (to_mount == entry->IsMounted())

+      (!to_mount && !entry->IsMounted())) {
+    *error = base::PLATFORM_FILE_ERROR_INVALID_OPERATION;
+    return;
+  }

[satorux1, 2012/04/18 23:29:04]

nit: maybe add a blank line here? The code here looks a bit too packed.

+  md5 = entry->md5;
+  // Get subdir types for the unmounted and mounted state.
+  GDataRootDirectory::CacheSubDirectoryType unmounted_subdir =
+      entry->IsPinned() ? GDataRootDirectory::CACHE_TYPE_PERSISTENT :
+                          GDataRootDirectory::CACHE_TYPE_TMP;
+  GDataRootDirectory::CacheSubDirectoryType mounted_subdir =
+      GDataRootDirectory::CACHE_TYPE_PERSISTENT;
+  // Gets path of the file if it were to be unmounted.
+  FilePath unmounted_path = GetCacheFilePath(resource_id, md5, unmounted_subdir,
+                                             CACHED_FILE_FROM_SERVER);
+  // Gets path of the file if it were to be mounted.
+  FilePath mounted_path = GetCacheFilePath(resource_id, md5, mounted_subdir,
+                                           CACHED_FILE_MOUNTED);

[satorux1, 2012/04/18 23:29:04]

add a blank line?

+  // Determine the source and destination paths for moving the cache blob.
+  FilePath source_path;
+  GDataRootDirectory::CacheSubDirectoryType dest_subdir;
+  int cache_state = entry->cache_state;
+  if (to_mount) {
+    source_path = unmounted_path;

[tbarzic, 2012/04/18 23:43:14]

I would find 
source_path = to_mount ? unmounted_path : mounted_path;
etc.
more readable (but I'm fine with this too)

+    *cache_file_path = mounted_path;
+    dest_subdir = mounted_subdir;
+    cache_state = GDataFile::SetCacheMounted(cache_state);
+  } else {
+    source_path = mounted_path;
+    *cache_file_path = unmounted_path;
+    dest_subdir = unmounted_subdir;
+    cache_state = GDataFile::ClearCacheMounted(cache_state);
+  }

[satorux1, 2012/04/18 23:29:04]

blank line?

+  // Move cache blob from source path to destination path.
+  *error = ModifyCacheState(source_path, *cache_file_path,
+                            GDataFileSystem::FILE_OPERATION_MOVE, FilePath(),
+                            false);
+  if (*error == base::PLATFORM_FILE_OK) {
+    // Now that cache operation is complete, update cache map
+    root_->UpdateCacheMap(resource_id, md5, dest_subdir, cache_state);
+  }
+}
+
 void GDataFileSystem::OnSetPinStateCompleted(
     const FileOperationCallback& callback,
     base::PlatformFileError error,
     const std::string& resource_id,
     const std::string& md5) {
   callback.Run(error);
 }
 
 void GDataFileSystem::OnGetAvailableSpace(
     const GetAvailableSpaceCallback& callback,
@@ skipping 1151 matching lines @@
   DCHECK(sub_dir_type != GDataRootDirectory::CACHE_TYPE_META);
 
   // Runs on any thread.
   // Filename is formatted as resource_id.md5, i.e. resource_id is the base
   // name and md5 is the extension.
   std::string base_name = GDataFileBase::EscapeUtf8FileName(resource_id);
   if (file_origin == CACHED_FILE_LOCALLY_MODIFIED) {
     DCHECK(sub_dir_type == GDataRootDirectory::CACHE_TYPE_PERSISTENT);
     base_name += FilePath::kExtensionSeparator;
     base_name += kLocallyModifiedFileExtension;
+  } else if (file_origin == CACHED_FILE_MOUNTED) {
+    DCHECK(sub_dir_type == GDataRootDirectory::CACHE_TYPE_PERSISTENT);
+    base_name += FilePath::kExtensionSeparator;
+    base_name += kMountedArchiveFileExtension;
   } else if (!md5.empty()) {
     base_name += FilePath::kExtensionSeparator;
     base_name += GDataFileBase::EscapeUtf8FileName(md5);
   }
   return cache_paths_[sub_dir_type].Append(base_name);
 }
 
 void GDataFileSystem::GetFromCache(const std::string& resource_id,
                                    const std::string& md5,
                                    const GetFromCacheCallback& callback) {
@@ skipping 222 matching lines @@
     FilePath* cache_file_path) {
   DCHECK(error);
   DCHECK(cache_file_path);
 
   // Lock to access cache map.
   base::AutoLock lock(lock_);
 
   GDataRootDirectory::CacheEntry* entry = root_->GetCacheEntry(resource_id,
                                                                md5);
   if (entry && entry->IsPresent()) {
+    CachedFileOrigin file_origin;
+    if (entry->IsMounted()) {
+      file_origin = CACHED_FILE_MOUNTED;
+    } else if (entry->IsDirty()) {
+      file_origin = CACHED_FILE_LOCALLY_MODIFIED;
+    } else {
+      file_origin = CACHED_FILE_FROM_SERVER;
+    }
     *cache_file_path = GetCacheFilePath(
         resource_id,
         md5,
         entry->sub_dir_type,
-        entry->IsDirty() ? CACHED_FILE_LOCALLY_MODIFIED :
-                           CACHED_FILE_FROM_SERVER);
+        file_origin);
     *error = base::PLATFORM_FILE_OK;
   } else {
     *error = base::PLATFORM_FILE_ERROR_NOT_FOUND;
   }
 }
 
 void GDataFileSystem::GetCacheStateOnIOThreadPool(
     const std::string& resource_id,
     const std::string& md5,
     base::PlatformFileError* error,
@@ skipping 36 matching lines @@
   int cache_state = GDataFile::CACHE_STATE_PRESENT;
   GDataRootDirectory::CacheSubDirectoryType sub_dir_type =
       GDataRootDirectory::CACHE_TYPE_TMP;
 
   GDataRootDirectory::CacheEntry* entry = root_->GetCacheEntry(
       resource_id, md5);
 
   // If file was previously pinned, store it in persistent dir and create
   // symlink in pinned dir.
   if (entry) {  // File exists in cache.
-    // If file is dirty, return error.
-    if (entry->IsDirty()) {
-      LOG(WARNING) << "Can't store a file to replace a dirty file: res_id="
-                   << resource_id
+    // If file is dirty or mounted, return error.
+    if (entry->IsDirty() || entry->IsMounted()) {
+      LOG(WARNING) << "Can't store a file to replace a "
+                   << (entry->IsDirty() ? "dirty" : "mounted")
+                   << " file: res_id=" << resource_id
                    << ", md5=" << md5;
       *error = base::PLATFORM_FILE_ERROR_IN_USE;
       return;
     }
 
     cache_state |= entry->cache_state;
 
     // If file is pinned, determines destination path.
     if (entry->IsPinned()) {
       sub_dir_type = GDataRootDirectory::CACHE_TYPE_PERSISTENT;
@@ skipping 78 matching lines @@
 
     // Set sub_dir_type to PINNED to indicate that the file doesn't exist.
     // When the file is finally downloaded and StoreToCache called, it will be
     // moved to persistent directory.
     sub_dir_type = GDataRootDirectory::CACHE_TYPE_PINNED;
   } else {  // File exists in cache, determines destination path.
     cache_state |= entry->cache_state;
 
     // Determine source and destination paths.
 
-    // If file is dirty, don't move it, so determine |dest_path| and set
-    // |source_path| the same, because ModifyCacheState only moves files if
+    // If file is dirty or mounted, don't move it, so determine |dest_path| and
+    // set |source_path| the same, because ModifyCacheState only moves files if
     // source and destination are different.
-    if (entry->IsDirty()) {
+    if (entry->IsDirty() || entry->IsMounted()) {
       DCHECK_EQ(GDataRootDirectory::CACHE_TYPE_PERSISTENT, entry->sub_dir_type);
       dest_path = GetCacheFilePath(resource_id,
                                    md5,
                                    entry->sub_dir_type,
                                    CACHED_FILE_LOCALLY_MODIFIED);
       source_path = dest_path;
     } else {
       // Gets the current path of the file in cache.
       source_path = GetCacheFilePath(resource_id,
                                      md5,
@@ skipping 59 matching lines @@
     return;
   }
 
   // Entry exists in cache, determines source and destination paths.
 
   FilePath source_path;
   FilePath dest_path;
   GDataRootDirectory::CacheSubDirectoryType sub_dir_type =
       GDataRootDirectory::CACHE_TYPE_TMP;
 
-  // If file is dirty, don't move it, so determine |dest_path| and set
-  // |source_path| the same, because ModifyCacheState moves files if source
+  // If file is dirty or mounted, don't move it, so determine |dest_path| and
+  // set |source_path| the same, because ModifyCacheState moves files if source
   // and destination are different.
-  if (entry->IsDirty()) {
+  if (entry->IsDirty() || entry->IsMounted()) {
     sub_dir_type = GDataRootDirectory::CACHE_TYPE_PERSISTENT;
     DCHECK_EQ(sub_dir_type, entry->sub_dir_type);
     dest_path = GetCacheFilePath(resource_id,
                                  md5,
                                  entry->sub_dir_type,
                                  CACHED_FILE_LOCALLY_MODIFIED);
     source_path = dest_path;
   } else {
     // Gets the current path of the file in cache.
     source_path = GetCacheFilePath(resource_id,
@@ skipping 311 matching lines @@
   // Lock to access cache map.
   base::AutoLock lock(lock_);
 
   // MD5 is not passed into RemoveFromCache and hence
   // RemoveFromCacheOnIOThreadPool, because we would delete all cache files
   // corresponding to <resource_id> regardless of the md5.
   // So, search for entry in cache without taking md5 into account.
   GDataRootDirectory::CacheEntry* entry = root_->GetCacheEntry(
       resource_id, std::string());
 
-  // If entry doesn't exist or is dirty in cache, nothing to do.
-  if (!entry || entry->IsDirty()) {
-    DVLOG(1) << "Entry " << (entry ? "is dirty" : "doesn't exist")
+  // If entry doesn't exist or is dirty or mounted in cache, nothing to do.
+  if (!entry || entry->IsDirty() || entry->IsMounted()) {
+    DVLOG(1) << "Entry is "
+             << (entry ? (entry->IsDirty() ? "dirty" : "mounted") :
+                         "non-existent")
              << " in cache, not removing";
     *error = base::PLATFORM_FILE_OK;
     return;
   }
 
   // Determine paths to delete all cache versions of |resource_id| in
   // persistent, tmp and pinned directories.
   std::vector<FilePath> paths_to_delete;
 
   // For files in persistent and tmp dirs, delete files that match
@@ skipping 258 matching lines @@
   pref_registrar_->Init(profile_->GetPrefs());
   pref_registrar_->Add(prefs::kDisableGDataHostedFiles, this);
 }
 
 void SetFreeDiskSpaceGetterForTesting(FreeDiskSpaceGetterInterface* getter) {
   delete global_free_disk_getter_for_testing;  // Safe to delete NULL;
   global_free_disk_getter_for_testing = getter;
 }
 
 }  // namespace gdata