[BlobStorage] BlobMemoryController & tests

storage/browser/blob/blob_data_builder.cc

Index: storage/browser/blob/blob_data_builder.cc
diff --git a/storage/browser/blob/blob_data_builder.cc b/storage/browser/blob/blob_data_builder.cc
index 1397cede297e47dbb88f2f52f3fa5f24172c39b9..3ec6b65e78e5b8d067ee4595a446b43b40f17be8 100644
--- a/storage/browser/blob/blob_data_builder.cc
+++ b/storage/browser/blob/blob_data_builder.cc
@@ -12,9 +12,10 @@
 
 #include "base/numerics/safe_conversions.h"
 #include "base/numerics/safe_math.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
 #include "base/time/time.h"
 #include "net/disk_cache/disk_cache.h"
-#include "storage/browser/blob/shareable_file_reference.h"
 
 namespace storage {
 
@@ -24,14 +25,35 @@ const static int kInvalidDiskCacheSideStreamIndex = -1;
 
 }  // namespace
 
-const char BlobDataBuilder::kAppendFutureFileTemporaryFileName[] =
-    "kFakeFilenameToBeChangedByPopulateFutureFile";
+const char kFutureFileName[] = "_future_name_";
 
-BlobDataBuilder::BlobDataBuilder(const std::string& uuid) : uuid_(uuid) {
+/* static */
+base::FilePath BlobDataBuilder::GetFutureFileItemPath(uint64_t file_id) {
+  return base::FilePath::FromUTF8Unsafe(kFutureFileName)
+      .AddExtension(base::Uint64ToString(file_id));
 }
-BlobDataBuilder::~BlobDataBuilder() {
+
+/* static */
+bool BlobDataBuilder::IsFutureFileItem(const DataElement& element) {
+  const std::string prefix(kFutureFileName);
+  const std::string path = element.path().MaybeAsASCII();
+  return path.size() >= prefix.size() &&

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

not sure the size comparison condition needed, StartsWith implies this test
built in.

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

Ah, right.Done.

+         base::StartsWith(path, prefix, base::CompareCase::SENSITIVE);

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

is there any chance that "_future_name_" is valid input from elsewhere? maybe
comment about how/why that can't happen

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

I mean, it's technically valid. I can DCHECK in AppendFile to make sure. Not
sure what else I can do.

[michaeln, 2016/10/04 00:11:54]

This seems like something we have to resolve? I don't think we should be able to
confuse actual input with _future_files_.

Are actual inputs required to be absolute paths? If so, I think we're good.

+}
+
+/* static */
+uint64_t BlobDataBuilder::GetFutureFileID(const DataElement& element) {
+  DCHECK(IsFutureFileItem(element));
+  uint64_t id = 0;
+  bool success =
+      base::StringToUint64(element.path().Extension().substr(1), &id);
+  DCHECK(success) << element.path().Extension();
+  return id;
 }
 
+BlobDataBuilder::BlobDataBuilder(const std::string& uuid) : uuid_(uuid) {}
+BlobDataBuilder::~BlobDataBuilder() {}
+
 void BlobDataBuilder::AppendIPCDataElement(const DataElement& ipc_data) {
   uint64_t length = ipc_data.length();
   switch (ipc_data.type()) {
@@ -83,7 +105,7 @@ bool BlobDataBuilder::PopulateFutureData(size_t index,
                                          size_t length) {
   DCHECK_LT(index, items_.size());
   DCHECK(data);
-  DataElement* element = items_.at(index)->data_element_ptr();
+  DataElement* element = items_[index]->data_element_ptr();
 
   // We lazily allocate our data buffer by waiting until the first
   // PopulateFutureData call.
@@ -110,12 +132,13 @@ bool BlobDataBuilder::PopulateFutureData(size_t index,
   return true;
 }
 
-size_t BlobDataBuilder::AppendFutureFile(uint64_t offset, uint64_t length) {
+size_t BlobDataBuilder::AppendFutureFile(uint64_t offset,
+                                         uint64_t length,
+                                         uint64_t file_id) {
   CHECK_NE(length, 0ull);
   std::unique_ptr<DataElement> element(new DataElement());
-  element->SetToFilePathRange(base::FilePath::FromUTF8Unsafe(std::string(
-                                  kAppendFutureFileTemporaryFileName)),
-                              offset, length, base::Time());
+  element->SetToFilePathRange(GetFutureFileItemPath(file_id), offset, length,
+                              base::Time());
   items_.push_back(new BlobDataItem(std::move(element)));
   return items_.size() - 1;
 }
@@ -125,22 +148,20 @@ bool BlobDataBuilder::PopulateFutureFile(
     const scoped_refptr<ShareableFileReference>& file_reference,
     const base::Time& expected_modification_time) {
   DCHECK_LT(index, items_.size());
-  DataElement* old_element = items_.at(index)->data_element_ptr();
+  DataElement* element = items_[index]->data_element_ptr();
 
-  if (old_element->type() != DataElement::TYPE_FILE) {
+  if (element->type() != DataElement::TYPE_FILE) {
     DVLOG(1) << "Invalid item type.";
     return false;
-  } else if (old_element->path().AsUTF8Unsafe() !=
-             std::string(kAppendFutureFileTemporaryFileName)) {
+  } else if (!IsFutureFileItem(*element)) {
     DVLOG(1) << "Item not created by AppendFutureFile";
     return false;
   }
-  uint64_t length = old_element->length();
-  uint64_t offset = old_element->offset();
-  std::unique_ptr<DataElement> element(new DataElement());
+  uint64_t length = element->length();
+  uint64_t offset = element->offset();
+  items_[index]->data_handle_ = std::move(file_reference);
   element->SetToFilePathRange(file_reference->path(), offset, length,
                               expected_modification_time);
-  items_[index] = new BlobDataItem(std::move(element), file_reference);
   return true;
 }