SERVER-19583: Implement full-time diagnostic data capture compressor and decompressor

1 files changed, 63 insertions, 0 deletions

diff --git a/src/mongo/db/ftdc/decompressor.h b/src/mongo/db/ftdc/decompressor.h
new file mode 100644
index 00000000000..42af2985783
--- /dev/null
+++ b/src/mongo/db/ftdc/decompressor.h
@@ -0,0 +1,63 @@
+/**
+ * Copyright (C) 2015 MongoDB Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ */
+
+#pragma once
+
+#include <vector>
+
+#include "mongo/base/data_range.h"
+#include "mongo/base/disallow_copying.h"
+#include "mongo/base/status_with.h"
+#include "mongo/db/ftdc/block_compressor.h"
+#include "mongo/db/jsobj.h"
+
+namespace mongo {
+
+/**
+ * Inflates a compressed chunk of metrics into a list of BSON documents
+ */
+class FTDCDecompressor {
+    MONGO_DISALLOW_COPYING(FTDCDecompressor);
+
+public:
+    FTDCDecompressor() = default;
+
+    /**
+     * Inflates a compressed chunk of metrics into a vector of owned BSON documents.
+     *
+     * Will fail if the chunk is corrupt or too short.
+     *
+     * Returns N samples where N = sample count + 1. The 1 is the reference document.
+     */
+    StatusWith<std::vector<BSONObj>> uncompress(ConstDataRange buf);
+
+private:
+    BlockCompressor _compressor;
+};
+
+}  // namespace mongo