LevelDB glue

Database-independent glue for supporting LevelDB databases.

Based on code from earlier commits by Mike Hearn in his leveldb
branch.

src/leveldb.cpp

@@ -0,0 +1,58 @@
+// Copyright (c) 2012 The Bitcoin developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "leveldb.h"
+#include "util.h"
+
+#include <leveldb/env.h>
+#include <leveldb/cache.h>
+#include <leveldb/filter_policy.h>
+
+#include <boost/filesystem.hpp>
+
+static leveldb::Options GetOptions() {
+    leveldb::Options options;
+    int nCacheSizeMB = GetArg("-dbcache", 25);
+    options.block_cache = leveldb::NewLRUCache(nCacheSizeMB * 1048576);
+    options.filter_policy = leveldb::NewBloomFilterPolicy(10);
+    options.compression = leveldb::kNoCompression;
+    return options;
+}
+
+CLevelDB::CLevelDB(const boost::filesystem::path &path) {
+    penv = NULL;
+    readoptions.verify_checksums = true;
+    iteroptions.verify_checksums = true;
+    iteroptions.fill_cache = false;
+    syncoptions.sync = true;
+    options = GetOptions();
+    options.create_if_missing = true;
+    boost::filesystem::create_directory(path);
+    printf("Opening LevelDB in %s\n", path.string().c_str());
+    leveldb::Status status = leveldb::DB::Open(options, path.string(), &pdb);
+    if (!status.ok())
+        throw std::runtime_error(strprintf("CLevelDB(): error opening database environment %s", status.ToString().c_str()));
+    printf("Opened LevelDB successfully\n");
+}
+
+CLevelDB::~CLevelDB() {
+    delete pdb;
+    pdb = NULL;
+    delete options.filter_policy;
+    options.filter_policy = NULL;
+    delete options.block_cache;
+    options.block_cache = NULL;
+    delete penv;
+    options.env = NULL;
+}
+
+bool CLevelDB::WriteBatch(CLevelDBBatch &batch, bool fSync) {
+    leveldb::Status status = pdb->Write(fSync ? syncoptions : writeoptions, &batch.batch);
+    if (!status.ok()) {
+        printf("LevelDB write failure: %s\n", status.ToString().c_str());
+        return false;
+    }
+    return true;
+}
+