ServiceWorker: Migrate the script cache backend from BlockFile to Simple

content/browser/service_worker/service_worker_database.cc

Index: content/browser/service_worker/service_worker_database.cc
diff --git a/content/browser/service_worker/service_worker_database.cc b/content/browser/service_worker/service_worker_database.cc
index 4da2ca77aa7de0fda7db944507d15f7e467bc4e5..7c5d352695d9004f1aa178d91038d2322468dfef 100644
--- a/content/browser/service_worker/service_worker_database.cc
+++ b/content/browser/service_worker/service_worker_database.cc
@@ -72,6 +72,12 @@
 //
 //   key: "REGID_TO_ORIGIN:" + <int64 'registration_id'>
 //   value: <GURL 'origin'>
+//
+//   key: "INITDATA_DISKCACHE_VERSION"

[michaeln, 2015/06/11 00:52:38]

It feels a little early to generalize a diskcache versioning scheme file
deletion mechanism. I think the plan is to remove the migration code after a few
release cycles. Would you expect to also remove this code at this time?

Consider something more specific to this blockfile -> simplecache migration, and
then to remove the code at some point.

[nhiroki, 2015/06/11 21:04:50]

I was thinking to keep these fields after migration code are removed and abuse
them for something. But, yeah..., it looks like overkill.
Ok, let's simplify them (Done).

+//   value: <int64 'current_disk_cache_version'>
+//
+//   key: "INITDATA_PURGEABLE_FILE:" + <string 'filename'>
+//   value: <empty>
 namespace content {
 
 namespace {
@@ -81,6 +87,8 @@ const char kNextRegIdKey[] = "INITDATA_NEXT_REGISTRATION_ID";
 const char kNextResIdKey[] = "INITDATA_NEXT_RESOURCE_ID";
 const char kNextVerIdKey[] = "INITDATA_NEXT_VERSION_ID";
 const char kUniqueOriginKey[] = "INITDATA_UNIQUE_ORIGIN:";
+const char kDiskCacheVersionKey[] = "INITDATA_DISKCACHE_VERSION";
+const char kPurgeableFileKey[] = "INITDATA_PURGEABLE_FILE:";
 
 const char kRegKeyPrefix[] = "REG:";
 const char kRegUserDataKeyPrefix[] = "REG_USER_DATA:";
@@ -88,6 +96,7 @@ const char kRegHasUserDataKeyPrefix[] = "REG_HAS_USER_DATA:";
 const char kRegIdToOriginKeyPrefix[] = "REGID_TO_ORIGIN:";
 const char kResKeyPrefix[] = "RES:";
 const char kKeySeparator = '\x00';
+const char kEmptyValue[] = "";
 
 const char kUncommittedResIdKeyPrefix[] = "URES:";
 const char kPurgeableResIdKeyPrefix[] = "PRES:";
@@ -408,6 +417,50 @@ ServiceWorkerDatabase::Status ServiceWorkerDatabase::GetNextAvailableIds(
   return STATUS_OK;
 }
 
+ServiceWorkerDatabase::Status ServiceWorkerDatabase::ReadDiskCacheVersion(
+    int64* disk_cache_version) {
+  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
+
+  Status status = LazyOpen(false);
+  if (IsNewOrNonexistentDatabase(status)) {
+    *disk_cache_version = 0;

[michaeln, 2015/06/11 00:52:38]

should this be kCurrentDiskCacheVersion?

[nhiroki, 2015/06/11 21:04:50]

(This code is gone)

+    return STATUS_OK;
+  }
+  if (status != STATUS_OK)
+    return status;
+
+  std::string value;
+  status = LevelDBStatusToStatus(
+      db_->Get(leveldb::ReadOptions(), kDiskCacheVersionKey, &value));
+  if (status == STATUS_ERROR_NOT_FOUND) {
+    *disk_cache_version = 0;
+    HandleReadResult(FROM_HERE, STATUS_OK);
+    return STATUS_OK;
+  }
+
+  if (status != STATUS_OK) {
+    HandleReadResult(FROM_HERE, status);
+    return status;
+  }
+
+  status = ParseId(value, disk_cache_version);
+  HandleReadResult(FROM_HERE, status);
+  return status;
+}
+
+ServiceWorkerDatabase::Status ServiceWorkerDatabase::WriteDiskCacheVersion(
+    int64 disk_cache_version) {
+  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
+
+  Status status = LazyOpen(false);
+  if (status != STATUS_OK)
+    return status;
+
+  leveldb::WriteBatch batch;
+  batch.Put(kDiskCacheVersionKey, base::Int64ToString(disk_cache_version));
+  return WriteBatch(&batch);
+}
+
 ServiceWorkerDatabase::Status
 ServiceWorkerDatabase::GetOriginsWithRegistrations(std::set<GURL>* origins) {
   DCHECK(sequence_checker_.CalledOnValidSequencedThread());
@@ -933,6 +986,74 @@ ServiceWorkerDatabase::PurgeUncommittedResourceIds(
   return WriteBatch(&batch);
 }
 
+ServiceWorkerDatabase::Status ServiceWorkerDatabase::GetPurgeableFiles(
+    std::vector<std::string>* filenames) {
+  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
+  DCHECK(filenames->empty());
+
+  Status status = LazyOpen(false);
+  if (IsNewOrNonexistentDatabase(status))
+    return STATUS_OK;
+  if (status != STATUS_OK)
+    return status;
+
+  scoped_ptr<leveldb::Iterator> itr(db_->NewIterator(leveldb::ReadOptions()));
+  for (itr->Seek(kPurgeableFileKey); itr->Valid(); itr->Next()) {
+    status = LevelDBStatusToStatus(itr->status());
+    if (status != STATUS_OK) {
+      HandleReadResult(FROM_HERE, status);
+      filenames->clear();
+      return status;
+    }
+
+    std::string filename;
+    if (!RemovePrefix(itr->key().ToString(), kPurgeableFileKey, &filename))
+      break;
+
+    if (filename.empty()) {
+      HandleReadResult(FROM_HERE, STATUS_ERROR_CORRUPTED);
+      filenames->clear();
+      return status;
+    }
+    filenames->push_back(filename);
+  }
+
+  HandleReadResult(FROM_HERE, status);
+  return status;
+}
+
+ServiceWorkerDatabase::Status ServiceWorkerDatabase::WritePurgeableFile(
+    const std::string& filename) {
+  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
+  if (filename.empty())

[michaeln, 2015/06/11 00:52:38]

when would we ever expect empty names here?

[nhiroki, 2015/06/11 21:04:50]

(This code is gone)

+    return ServiceWorkerDatabase::STATUS_OK;
+
+  Status status = LazyOpen(true);
+  if (status != STATUS_OK)
+    return status;
+
+  leveldb::WriteBatch batch;
+  batch.Put(std::string(kPurgeableFileKey).append(filename), kEmptyValue);
+  return WriteBatch(&batch);
+}
+
+ServiceWorkerDatabase::Status ServiceWorkerDatabase::ClearPurgeableFile(
+    const std::string& filename) {
+  DCHECK(sequence_checker_.CalledOnValidSequencedThread());
+  if (filename.empty())
+    return ServiceWorkerDatabase::STATUS_OK;
+
+  Status status = LazyOpen(false);
+  if (IsNewOrNonexistentDatabase(status))
+    return STATUS_OK;
+  if (status != STATUS_OK)
+    return status;
+
+  leveldb::WriteBatch batch;
+  batch.Delete(std::string(kPurgeableFileKey).append(filename));
+  return WriteBatch(&batch);
+}
+
 ServiceWorkerDatabase::Status ServiceWorkerDatabase::DeleteAllDataForOrigins(
     const std::set<GURL>& origins,
     std::vector<int64>* newly_purgeable_resources) {