Fix build caused by DeleteFile not tolerating / at the beginning

Summary: db->DeleteFile calls ParseFileName to check name that was returned for sst file. Now, sst filename is returned using TableFileName which uses MakeFileName. This puts a / at the front of the name and ParseFileName doesn't like that. Changed ParseFileName to tolerate /s at the beginning. The test delet_file_test used to pass earlier because this behaviour of MakeFileName had been changed a while back to not return a / during which delete_file_test was checked in. But MakeFileName had to be reverted to add / at the front because GetLiveFiles used at many places outside rocksdb used the previous behaviour of MakeFileName.

Test Plan: make;./delete_filetest;make all check

Reviewers: dhruba, haobo, vamsi

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D12663

db/db_impl.cc

@@ -3042,8 +3042,7 @@ Status DBImpl::DeleteFile(std::string name) {
   return status;
 }
 
-void DBImpl::GetLiveFilesMetaData(
+void DBImpl::GetLiveFilesMetaData(std::vector<LiveFileMetaData> *metadata) {
-  std::vector<LiveFileMetaData> *metadata) {
   MutexLock l(&mutex_);
   return versions_->GetLiveFilesMetaData(metadata);
 }

db/deletefile_test.cc

@@ -167,7 +167,7 @@ TEST(DeleteFileTest, DeleteFileWithIterator) {
   }
 
   Status status = db_->DeleteFile(level2file);
-  fprintf(stderr, "Deletion status %s: %s\n",
+  fprintf(stdout, "Deletion status %s: %s\n",
           level2file.c_str(), status.ToString().c_str());
   ASSERT_TRUE(status.ok());
   it->SeekToFirst();

db/filename.cc

@@ -130,10 +130,14 @@ std::string MetaDatabaseName(const std::string& dbname, uint64_t number) {
 //    dbname/MANIFEST-[0-9]+
 //    dbname/[0-9]+.(log|sst)
 //    dbname/METADB-[0-9]+
+//    Disregards / at the beginning
 bool ParseFileName(const std::string& fname,
                    uint64_t* number,
                    FileType* type) {
   Slice rest(fname);
+  if (fname.length() > 1 && fname[0] == '/') {
+    rest.remove_prefix(1);
+  }
   if (rest == "CURRENT") {
     *number = 0;
     *type = kCurrentFile;