import quincy beta 17.1.0

[ceph.git] / ceph / src / rocksdb / db / blob / blob_log_writer.h

diff --git a/ceph/src/rocksdb/db/blob/blob_log_writer.h b/ceph/src/rocksdb/db/blob/blob_log_writer.h
new file mode 100644 (file)
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+++ b/ceph/src/rocksdb/db/blob/blob_log_writer.h
@@ -0,0 +1,83 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+#pragma once
+
+#include <cstdint>
+#include <memory>
+#include <string>
+
+#include "db/blob/blob_log_format.h"
+#include "rocksdb/env.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/statistics.h"
+#include "rocksdb/status.h"
+#include "rocksdb/types.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class WritableFileWriter;
+
+/**
+ * BlobLogWriter is the blob log stream writer. It provides an append-only
+ * abstraction for writing blob data.
+ *
+ *
+ * Look at blob_db_format.h to see the details of the record formats.
+ */
+
+class BlobLogWriter {
+ public:
+  // Create a writer that will append data to "*dest".
+  // "*dest" must be initially empty.
+  // "*dest" must remain live while this BlobLogWriter is in use.
+  BlobLogWriter(std::unique_ptr<WritableFileWriter>&& dest, Env* env,
+                Statistics* statistics, uint64_t log_number, bool use_fsync,
+                uint64_t boffset = 0);
+  // No copying allowed
+  BlobLogWriter(const BlobLogWriter&) = delete;
+  BlobLogWriter& operator=(const BlobLogWriter&) = delete;
+
+  ~BlobLogWriter();
+
+  static void ConstructBlobHeader(std::string* buf, const Slice& key,
+                                  const Slice& val, uint64_t expiration);
+
+  Status AddRecord(const Slice& key, const Slice& val, uint64_t* key_offset,
+                   uint64_t* blob_offset);
+
+  Status AddRecord(const Slice& key, const Slice& val, uint64_t expiration,
+                   uint64_t* key_offset, uint64_t* blob_offset);
+
+  Status EmitPhysicalRecord(const std::string& headerbuf, const Slice& key,
+                            const Slice& val, uint64_t* key_offset,
+                            uint64_t* blob_offset);
+
+  Status AppendFooter(BlobLogFooter& footer, std::string* checksum_method,
+                      std::string* checksum_value);
+
+  Status WriteHeader(BlobLogHeader& header);
+
+  WritableFileWriter* file() { return dest_.get(); }
+
+  const WritableFileWriter* file() const { return dest_.get(); }
+
+  uint64_t get_log_number() const { return log_number_; }
+
+  Status Sync();
+
+ private:
+  std::unique_ptr<WritableFileWriter> dest_;
+  Env* env_;
+  Statistics* statistics_;
+  uint64_t log_number_;
+  uint64_t block_offset_;  // Current offset in block
+  bool use_fsync_;
+
+ public:
+  enum ElemType { kEtNone, kEtFileHdr, kEtRecord, kEtFileFooter };
+  ElemType last_elem_type_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE