1 files changed, 266 insertions, 0 deletions

diff --git a/common/storage_lmdb.cpp b/common/storage_lmdb.cpp
new file mode 100644
index 0000000..6c25448
--- /dev/null
+++ b/common/storage_lmdb.cpp
@@ -0,0 +1,266 @@
+#include "storage.h"
+
+#include <iostream>
+
+#include <QAtomicInt>
+#include <QDebug>
+#include <QDir>
+#include <QReadWriteLock>
+#include <QString>
+#include <QTime>
+
+#include <lmdb.h>
+
+class Storage::Private
+{
+public:
+    Private(const QString &p);
+    ~Private();
+
+    QString path;
+    MDB_dbi dbi;
+    MDB_env *env;
+    MDB_txn *transaction;
+    bool readTransaction;
+    bool firstOpen;
+};
+
+Storage::Private::Private(const QString &p)
+    : path(p),
+      transaction(0),
+      readTransaction(false),
+      firstOpen(true)
+{
+    QDir dir;
+    dir.mkdir(path);
+
+    //create file
+    if (mdb_env_create(&env)) {
+        // TODO: handle error
+    } else {
+        int rc = mdb_env_open(env, path.toStdString().data(), 0, 0664);
+
+        if (rc) {
+            std::cerr << "mdb_env_open: " << rc << " " << mdb_strerror(rc) << std::endl;
+            mdb_env_close(env);
+            env = 0;
+        } else {
+            const size_t dbSize = 10485760 * 100; //10MB * 100
+            mdb_env_set_mapsize(env, dbSize);
+        }
+    }
+}
+
+Storage::Private::~Private()
+{
+    if (transaction) {
+        mdb_txn_abort(transaction);
+    }
+
+    // it is still there and still unused, so we can shut it down
+    mdb_dbi_close(env, dbi);
+    mdb_env_close(env);
+}
+
+Storage::Storage(const QString &storageRoot, const QString &name)
+    : d(new Private(storageRoot + '/' + name))
+{
+}
+
+Storage::~Storage()
+{
+    delete d;
+}
+
+bool Storage::isInTransaction() const
+{
+    return d->transaction;
+}
+
+bool Storage::startTransaction(TransactionType type)
+{
+    if (!d->env) {
+        return false;
+    }
+
+    bool requestedRead = type == ReadOnly;
+    if (d->transaction && (!d->readTransaction || requestedRead)) {
+        return true;
+    }
+
+    if (d->transaction) {
+        // we are about to turn a read transaction into a writable one
+        abortTransaction();
+    }
+
+    if (d->firstOpen && requestedRead) {
+        //A write transaction is at least required the first time
+        mdb_txn_begin(d->env, nullptr, 0, &d->transaction);
+        //Open the database
+        //With this we could open multiple named databases if we wanted to
+        mdb_dbi_open(d->transaction, nullptr, 0, &d->dbi);
+        mdb_txn_abort(d->transaction);
+    }
+
+    int rc;
+    rc = mdb_txn_begin(d->env, NULL, requestedRead ? MDB_RDONLY : 0, &d->transaction);
+    if (!rc) {
+        rc = mdb_dbi_open(d->transaction, NULL, 0, &d->dbi);
+    }
+
+    d->firstOpen = false;
+    return !rc;
+}
+
+bool Storage::commitTransaction()
+{
+    if (!d->env) {
+        return false;
+    }
+
+    if (!d->transaction) {
+        return false;
+    }
+
+    int rc;
+    rc = mdb_txn_commit(d->transaction);
+    d->transaction = 0;
+
+    if (rc) {
+        std::cerr << "mdb_txn_commit: " << rc << " " << mdb_strerror(rc) << std::endl;
+    }
+
+    return !rc;
+}
+
+void Storage::abortTransaction()
+{
+    if (!d->env || !d->transaction) {
+        return;
+    }
+
+    mdb_txn_abort(d->transaction);
+    d->transaction = 0;
+}
+
+bool Storage::write(const std::string &sKey, const std::string &sValue)
+{
+    if (!d->env) {
+        return false;
+    }
+
+    const bool implicitTransaction = !d->transaction || d->readTransaction;
+    if (implicitTransaction) {
+        // TODO: if this fails, still try the write below?
+        if (!startTransaction()) {
+            return false;
+        }
+    }
+
+    int rc;
+    MDB_val key, data;
+    key.mv_size = sKey.size();
+    key.mv_data = (void*)sKey.data();
+    data.mv_size = sValue.size();
+    data.mv_data = (void*)sValue.data();
+    rc = mdb_put(d->transaction, d->dbi, &key, &data, 0);
+
+    if (rc) {
+        std::cerr << "mdb_put: " << rc << " " << mdb_strerror(rc) << std::endl;
+    }
+
+    if (implicitTransaction) {
+        if (rc) {
+            abortTransaction();
+        } else {
+            rc = commitTransaction();
+        }
+    }
+
+    return !rc;
+}
+
+void Storage::read(const std::string &sKey, const std::function<void(const std::string &value)> &resultHandler)
+{
+    read(sKey,
+         [&](void *ptr, int size) {
+            const std::string resultValue(static_cast<char*>(ptr), size);
+            resultHandler(resultValue);
+         });
+// std::cout << "key: " << resultKey << " data: " << resultValue << std::endl;
+}
+
+void Storage::read(const std::string &sKey, const std::function<void(void *ptr, int size)> &resultHandler)
+{
+    if (!d->env) {
+        return;
+    }
+
+    int rc;
+    MDB_val key;
+    MDB_val data;
+    MDB_cursor *cursor;
+
+    key.mv_size = sKey.size();
+    key.mv_data = (void*)sKey.data();
+
+    const bool implicitTransaction = !d->transaction;
+    if (implicitTransaction) {
+        // TODO: if this fails, still try the write below?
+        if (!startTransaction(ReadOnly)) {
+            return;
+        }
+    }
+
+    rc = mdb_cursor_open(d->transaction, d->dbi, &cursor);
+    if (rc) {
+        std::cerr << "mdb_cursor_get: " << rc << " " << mdb_strerror(rc) << std::endl;
+        return;
+    }
+
+    if (sKey.empty()) {
+        std::cout << "Iterating over all values of store!" << std::endl;
+        rc = mdb_cursor_get(cursor, &key, &data, MDB_FIRST);
+        while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
+            resultHandler(key.mv_data, data.mv_size);
+        }
+
+        //We never find the last value
+        if (rc == MDB_NOTFOUND) {
+            rc = 0;
+        }
+    } else {
+        if ((rc = mdb_cursor_get(cursor, &key, &data, MDB_SET)) == 0) {
+            resultHandler(data.mv_data, data.mv_size);
+        } else {
+            std::cout << "couldn't find value " << sKey << " " << std::endl;
+        }
+    }
+
+    if (rc) {
+        std::cerr << "mdb_cursor_get: " << rc << " " << mdb_strerror(rc) << std::endl;
+    }
+
+    mdb_cursor_close(cursor);
+
+    /**
+      we don't abort the transaction since we need it for reading the values
+    if (implicitTransaction) {
+        abortTransaction();
+    }
+    */
+}
+
+qint64 Storage::diskUsage() const
+{
+    QFileInfo info(d->path, "data.mdb");
+    return info.size();
+}
+
+void Storage::removeFromDisk() const
+{
+    QDir dir(d->path);
+    dir.remove("data.mdb");
+    dir.remove("lock.mdb");
+}
+