[BlobStorage] BlobMemoryController & tests

storage/browser/blob/blob_data_builder.h

Index: storage/browser/blob/blob_data_builder.h
diff --git a/storage/browser/blob/blob_data_builder.h b/storage/browser/blob/blob_data_builder.h
index f304f446555cff8fa0f9291fea32bb2a95b72051..8370c9c84df3fd72cbdf3cd87b03c12bd6191a7a 100644
--- a/storage/browser/blob/blob_data_builder.h
+++ b/storage/browser/blob/blob_data_builder.h
@@ -16,6 +16,7 @@
 #include "base/memory/ref_counted.h"
 #include "storage/browser/blob/blob_data_item.h"
 #include "storage/browser/blob/blob_data_snapshot.h"
+#include "storage/browser/blob/shareable_file_reference.h"
 #include "storage/browser/storage_browser_export.h"
 
 namespace disk_cache {
@@ -26,13 +27,21 @@ namespace storage {
 class BlobStorageContext;
 class ShareableFileReference;
 
+// This class is used to build blobs. It also facilitates the operation of
+// 'pending' data, where the user knows the size and existence of a file or
+// bytes item, but we don't have the memory or file yet. See AppendFuture* and
+// PopulateFuture* methods for more description. Use
+// BlobDataHandle::GetBlobStatus to check for an error after creating the blob.
 class STORAGE_EXPORT BlobDataBuilder {
  public:
   using DataHandle = BlobDataItem::DataHandle;
+  // Visible for testing.
+  static base::FilePath GetFutureFileItemPath(uint64_t file_id);
 
-  // This is the filename used for the temporary file items added by
-  // AppendFutureFile.
-  const static char kAppendFutureFileTemporaryFileName[];
+  // Returns if the given item was created by AppendFutureFile.
+  static bool IsFutureFileItem(const DataElement& element);
+  // Returns |file_id| given to AppendFutureFile.
+  static uint64_t GetFutureFileID(const DataElement& element);
 
   explicit BlobDataBuilder(const std::string& uuid);
   ~BlobDataBuilder();
@@ -73,9 +82,13 @@ class STORAGE_EXPORT BlobDataBuilder {
   // Adds an item that is flagged for future data population. Use
   // 'PopulateFutureFile' to set the file path and expected modification time
   // of this file. Returns the index of the item (to be used in
-  // PopulateFutureFile). The temporary filename used by this method is
-  // kAppendFutureFileTemporaryFileName. |length| cannot be 0.
-  size_t AppendFutureFile(uint64_t offset, uint64_t length);
+  // PopulateFutureFile). |length| cannot be 0.
+  // |file_id| corresponds to the file handle index used to store this item,
+  // which needs to be unique on a per-builder bases. Multiple items can have

[michaeln, 2016/09/27 00:09:29]

basis (sp)
as worded the comments are a little confusing, file_id is unique but there can
be duplicates. you explained this more clearly in an earlier review comment,
"data for multiple items can be stored in the same file at different offsets".

[dmurph, 2016/09/29 00:44:20]

Ah, yeah. I tried to make this more clear, let me know if it makes sense now.

+  // the same id (as they would be at diffeent offsets in the file). This is
+  // used by the BlobMemoryController class to determine the number and size of
+  // files it needs to create for a blob.
+  size_t AppendFutureFile(uint64_t offset, uint64_t length, uint64_t file_id);
 
   // Populates a part of an item previously allocated with AppendFutureFile.
   // Returns true if:
@@ -106,6 +119,7 @@ class STORAGE_EXPORT BlobDataBuilder {
   void AppendDiskCacheEntry(const scoped_refptr<DataHandle>& data_handle,
                             disk_cache::Entry* disk_cache_entry,
                             int disk_cache_stream_index);
+
   // The content of the side data is accessible with BlobReader::ReadSideData().
   void AppendDiskCacheEntryWithSideData(
       const scoped_refptr<DataHandle>& data_handle,
@@ -124,12 +138,14 @@ class STORAGE_EXPORT BlobDataBuilder {
   void Clear();
 
  private:
+  friend class BlobMemoryControllerTest;
   friend class BlobStorageContext;
-  friend class BlobAsyncBuilderHostTest;
   friend bool operator==(const BlobDataBuilder& a, const BlobDataBuilder& b);
   friend bool operator==(const BlobDataSnapshot& a, const BlobDataBuilder& b);
   friend STORAGE_EXPORT void PrintTo(const BlobDataBuilder& x,
                                      ::std::ostream* os);
+  FRIEND_TEST_ALL_PREFIXES(BlobDataBuilderTest, TestFutureFiles);
+  FRIEND_TEST_ALL_PREFIXES(BlobStorageContextTest, BuildBlobFuzzy);
 
   std::string uuid_;
   std::string content_type_;