Bug 1133763 - Part 3: Wipe out the cache directory when detecting a change in the DB schema; r=bkelly

dom/cache/DBAction.cpp

@@ -14,6 +14,8 @@
 #include "nsIFile.h"
 #include "nsIURI.h"
 #include "nsNetUtil.h"
+#include "DBSchema.h"
+#include "FileUtils.h"
 
 namespace mozilla {
 namespace dom {
@@ -75,6 +77,8 @@ DBAction::OpenConnection(const QuotaInfo& aQuotaInfo, nsIFile* aDBDir,
   MOZ_ASSERT(aDBDir);
   MOZ_ASSERT(aConnOut);
 
+  nsCOMPtr<mozIStorageConnection> conn;
+
   bool exists;
   nsresult rv = aDBDir->Exists(&exists);
   if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
@@ -123,21 +127,48 @@ DBAction::OpenConnection(const QuotaInfo& aQuotaInfo, nsIFile* aDBDir,
     do_GetService(MOZ_STORAGE_SERVICE_CONTRACTID);
   if (NS_WARN_IF(!ss)) { return NS_ERROR_UNEXPECTED; }
 
-  rv = ss->OpenDatabaseWithFileURL(dbFileUrl, aConnOut);
+  rv = ss->OpenDatabaseWithFileURL(dbFileUrl, getter_AddRefs(conn));
   if (rv == NS_ERROR_FILE_CORRUPTED) {
     NS_WARNING("Cache database corrupted. Recreating empty database.");
 
+    conn = nullptr;
+
     // There is nothing else we can do to recover.  Also, this data can
     // be deleted by QuotaManager at any time anyways.
-    rv = dbFile->Remove(false);
+    rv = WipeDatabase(dbFile, aDBDir);
     if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
 
-    // TODO: clean up any orphaned body files (bug 1110446)
-
-    rv = ss->OpenDatabaseWithFileURL(dbFileUrl, aConnOut);
+    rv = ss->OpenDatabaseWithFileURL(dbFileUrl, getter_AddRefs(conn));
   }
   if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
-  MOZ_ASSERT(*aConnOut);
+
+  // Check the schema to make sure it is not too old.
+  int32_t schemaVersion = 0;
+  rv = conn->GetSchemaVersion(&schemaVersion);
+  if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+  if (schemaVersion > 0 && schemaVersion < DBSchema::kMaxWipeSchemaVersion) {
+    conn = nullptr;
+    rv = WipeDatabase(dbFile, aDBDir);
+    if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+
+    rv = ss->OpenDatabaseWithFileURL(dbFileUrl, getter_AddRefs(conn));
+  }
+
+  conn.forget(aConnOut);
+
+  return rv;
+}
+
+nsresult
+DBAction::WipeDatabase(nsIFile* aDBFile, nsIFile* aDBDir)
+{
+  nsresult rv = aDBFile->Remove(false);
+  if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+
+  // Delete the morgue as well.
+  rv = FileUtils::BodyDeleteDir(aDBDir);
+  if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+
   return rv;
 }
 

dom/cache/DBAction.h

@@ -49,6 +49,8 @@ private:
   nsresult OpenConnection(const QuotaInfo& aQuotaInfo, nsIFile* aQuotaDir,
                           mozIStorageConnection** aConnOut);
 
+  nsresult WipeDatabase(nsIFile* aDBFile, nsIFile* aDBDir);
+
   const Mode mMode;
 };
 

dom/cache/DBSchema.cpp

@@ -20,6 +20,7 @@ namespace dom {
 namespace cache {
 
 
+const int32_t DBSchema::kMaxWipeSchemaVersion = 1;
 const int32_t DBSchema::kLatestSchemaVersion = 1;
 const int32_t DBSchema::kMaxEntriesPerStatement = 255;
 

dom/cache/DBSchema.h

@@ -88,6 +88,9 @@ public:
                                  Namespace aNamespace,
                                  nsTArray<nsString>& aKeysOut);
 
+  // We will wipe out databases with a schema versions less than this.
+  static const int32_t kMaxWipeSchemaVersion;
+
 private:
   typedef int32_t EntryId;
 

dom/cache/FileUtils.cpp

@@ -47,6 +47,29 @@ FileUtils::BodyCreateDir(nsIFile* aBaseDir)
   return rv;
 }
 
+// static
+nsresult
+FileUtils::BodyDeleteDir(nsIFile* aBaseDir)
+{
+  MOZ_ASSERT(aBaseDir);
+
+  nsCOMPtr<nsIFile> aBodyDir;
+  nsresult rv = aBaseDir->Clone(getter_AddRefs(aBodyDir));
+  if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+
+  rv = aBodyDir->Append(NS_LITERAL_STRING("morgue"));
+  if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+
+  rv = aBodyDir->Remove(/* recursive = */ true);
+  if (rv == NS_ERROR_FILE_NOT_FOUND ||
+      rv == NS_ERROR_FILE_TARGET_DOES_NOT_EXIST) {
+    rv = NS_OK;
+  }
+  if (NS_WARN_IF(NS_FAILED(rv))) { return rv; }
+
+  return rv;
+}
+
 // static
 nsresult
 FileUtils::BodyGetCacheDir(nsIFile* aBaseDir, const nsID& aId,

dom/cache/FileUtils.h

@@ -30,6 +30,10 @@ public:
   };
 
   static nsresult BodyCreateDir(nsIFile* aBaseDir);
+  // Note that this function can only be used during the initialization of the
+  // database.  We're unlikely to be able to delete the DB successfully past
+  // that point due to the file being in use.
+  static nsresult BodyDeleteDir(nsIFile* aBaseDir);
   static nsresult BodyGetCacheDir(nsIFile* aBaseDir, const nsID& aId,
                                   nsIFile** aCacheDirOut);