gdata: Support mounting archive files in GData cache.

chrome/browser/chromeos/gdata/gdata_file_system.cc

Index: chrome/browser/chromeos/gdata/gdata_file_system.cc
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system.cc b/chrome/browser/chromeos/gdata/gdata_file_system.cc
index c08061475799f53f66dce5bf03940036066de51a..58d5f5c12144e77483b3fd91c9e2550b9ecf7d9a 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system.cc
+++ b/chrome/browser/chromeos/gdata/gdata_file_system.cc
@@ -58,6 +58,7 @@ 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");
@@ -509,6 +510,18 @@ void RunGetFromCacheCallbackHelper(
     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,
@@ -1939,6 +1952,10 @@ bool GDataFileSystem::GetFileInfoFromPath(
   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];
 }
@@ -2087,6 +2104,98 @@ void GDataFileSystem::SetPinState(const FilePath& file_path, bool to_pin,
     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,
+                 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_);
+
+  // Parse file path to obtain resource_id, md5 and extra_extension.
+  std::string resource_id;
+  std::string md5;
+  std::string extra_extension;
+  util::ParseCacheFilePath(file_path, &resource_id, &md5, &extra_extension);
+  // The extra_extension can only be ".mounted" when unmounting.

[tbarzic, 2012/04/23 18:03:22]

The comment is a bit confusing.  Can you put "If we're unmounting the extra
extension must be ".mounted"." (Or something similar)
Btw. can the extension be .mounted if we are doing mount operation (if not, we
may want to check that too)?

[hshi, 2012/04/23 18:56:22]

How about the following

  // The extra_extension shall be ".mounted" if and only if we're unmounting.
  DCHECK(!to_mount == (extra_extension == kMountedArchiveFileExtension));

On 2012/04/23 18:03:22, tbarzic wrote:

[tbarzic, 2012/04/23 19:02:52]

sg (you could probably write iff instead of "if and only if")

On 2012/04/23 18:56:22, hshi wrote:

+  DCHECK(to_mount || extra_extension == kMountedArchiveFileExtension);
+
+  // Get cache entry associated with the resource_id and md5
+  GDataRootDirectory::CacheEntry* entry = root_->GetCacheEntry(resource_id,
+                                                               md5);
+  if (!entry) {
+    *error = base::PLATFORM_FILE_ERROR_NOT_FOUND;
+    return;
+  }
+  if (to_mount == entry->IsMounted()) {
+    *error = base::PLATFORM_FILE_ERROR_INVALID_OPERATION;
+    return;
+  }
+
+  // Get subdir types for the unmounted and mounted state.
+  GDataRootDirectory::CacheSubDirectoryType unmounted_subdir =
+      entry->IsPinned() ? GDataRootDirectory::CACHE_TYPE_PERSISTENT :
+                          GDataRootDirectory::CACHE_TYPE_TMP;

[tbarzic, 2012/04/23 18:03:22]

Optional (but really optional:)): I think rearranging this block of code like
this would make it easier to follow:
unmount_subdir =…
unmounted_path =…

mount_subdir =…
mounted_path =…

+  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);
+
+  // 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;
+    *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);
+  }
+
+  // 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,
@@ -3268,6 +3377,13 @@ FilePath GDataFileSystem::GetCacheFilePath(
     base_name += FilePath::kExtensionSeparator;
     base_name += GDataEntry::EscapeUtf8FileName(md5);
   }
+  // For mounted archives the filename is formatted as resource_id.md5.mounted,
+  // i.e. resource_id.md5 is the base name and ".mounted" is the extension
+  if (file_origin == CACHED_FILE_MOUNTED) {
+     DCHECK(sub_dir_type == GDataRootDirectory::CACHE_TYPE_PERSISTENT);
+     base_name += FilePath::kExtensionSeparator;
+     base_name += kMountedArchiveFileExtension;
+  }
   return cache_paths_[sub_dir_type].Append(base_name);
 }
 
@@ -3506,12 +3622,19 @@ void GDataFileSystem::GetFromCacheOnIOThreadPool(
   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;
@@ -3568,10 +3691,11 @@ void GDataFileSystem::StoreToCacheOnIOThreadPool(
   // 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;
@@ -3670,10 +3794,10 @@ void GDataFileSystem::PinOnIOThreadPool(const std::string& resource_id,
 
     // 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,
@@ -3753,10 +3877,10 @@ void GDataFileSystem::UnpinOnIOThreadPool(const std::string& resource_id,
   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,
@@ -4088,9 +4212,11 @@ void GDataFileSystem::RemoveFromCacheOnIOThreadPool(
   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;
@@ -4212,23 +4338,10 @@ void GDataFileSystem::ScanCacheDirectory(
   for (FilePath current = enumerator.Next(); !current.empty();
        current = enumerator.Next()) {
     // Extract resource_id and md5 from filename.
-    FilePath base_name = current.BaseName();
     std::string resource_id;
     std::string md5;
-
-    // Pinned and outgoing symlinks have no extension.
-    if (sub_dir_type == GDataRootDirectory::CACHE_TYPE_PINNED ||
-        sub_dir_type == GDataRootDirectory::CACHE_TYPE_OUTGOING) {
-      resource_id = GDataEntry::UnescapeUtf8FileName(base_name.value());
-    } else {
-      FilePath::StringType extension = base_name.Extension();
-      if (!extension.empty()) {
-        // FilePath::Extension returns ".", so strip it.
-        md5 = GDataEntry::UnescapeUtf8FileName(extension.substr(1));
-      }
-      resource_id = GDataEntry::UnescapeUtf8FileName(
-          base_name.RemoveExtension().value());
-    }
+    std::string extra_extension;
+    util::ParseCacheFilePath(current, &resource_id, &md5, &extra_extension);
 
     // Determine cache state.
     int cache_state = GDataFile::CACHE_STATE_NONE;
@@ -4260,6 +4373,12 @@ void GDataFileSystem::ScanCacheDirectory(
         NOTREACHED() << "Dirty cache file MUST have actual file blob";
       }
       continue;
+    } else if (extra_extension == kMountedArchiveFileExtension) {
+      // Mounted archives in cache should be unmounted upon logout/shutdown.
+      // But if we encounter a mounted file at start, delete it and create an
+      // entry with not PRESENT state.
+      DCHECK(sub_dir_type == GDataRootDirectory::CACHE_TYPE_PERSISTENT);
+      file_util::Delete(current, false);
     } else {
       // Scanning other directories means that cache file is actually present.
       cache_state = GDataFile::SetCachePresent(cache_state);