[ADD/WIP] Start to add LMDB operations

src/Db/LMDB.c

@@ -1,30 +1,270 @@
 #include <Memory.h>
-
+#include <Json.h>
+#include <Log.h>
 #include <Db.h>
 
 #include "Db/Internal.h"
 
-#ifdef EDB_LMDB
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+
+#ifdef EDB_IMPL
+
+#include <lmdb.h>
 
 typedef struct LMDB {
     Db base; /* The base implementation required to pass */
+
+    MDB_env *environ;
 } LMDB;
+typedef struct LMDBRef {
+    DbRef base;
+
+    /* TODO: LMDB-dependent stuff */
+    MDB_txn *transaction;
+    MDB_dbi dbi;
+} LMDBRef;
+
+/* Helper functions */
+static MDB_val
+LMDBTranslateKey(Array *key)
+{
+    MDB_val ret = { 0 };
+    char *data = NULL;
+    size_t length = 0;
+    size_t i;
+    if (!key || ArraySize(key) > 255)
+    {
+        return ret;
+    }
+
+    data = Realloc(data, ++length);
+    data[0] = ArraySize(key);
+
+    /* Now, let's push every item */
+    for (i = 0; i < ArraySize(key); i++)
+    {
+        char *entry = ArrayGet(key, i);
+        size_t offset = length;
+
+        data = Realloc(data, (length += strlen(entry) + 1));
+        memcpy(data + offset, entry, strlen(entry));
+        data[length - 1] = '\0';
+    }
+
+    /* We now have every key */
+    ret.mv_size = length;
+    ret.mv_data = data;
+    return ret;
+}
+static void
+LMDBKillKey(MDB_val key)
+{
+    if (!key.mv_data || !key.mv_size)
+    {
+        return;
+    }
+
+    Free(key.mv_data);
+}
+
+static bool
+LMDBUnlock(Db *d, DbRef *r)
+{
+    LMDBRef *ref = (LMDBRef *) r;
+    LMDB *db = (LMDB *) d;
+    FILE *fakestream;
+    Stream *stream;
+    MDB_val key, val;
+    bool ret;
+
+    if (!d || !r)
+    {
+        return false;
+    }
+
+    val.mv_data = NULL;
+    val.mv_size = 0;
+    key = LMDBTranslateKey(r->name);
+
+    fakestream = open_memstream((char **) &val.mv_data, &val.mv_size);
+    stream = StreamFile(fakestream);
+    JsonEncode(r->json, stream, JSON_DEFAULT);
+    StreamFlush(stream);
+    StreamClose(stream);
+
+    mdb_put(ref->transaction, ref->dbi, &key, &val, 0);
+
+    mdb_txn_commit(ref->transaction);
+    mdb_dbi_close(db->environ, ref->dbi);
+    StringArrayFree(ref->base.name);
+    JsonFree(ref->base.json);
+    Free(ref);
+
+    LMDBKillKey(key);
+    if (val.mv_data)
+    {
+        free(val.mv_data);
+    }
+    pthread_mutex_unlock(&d->lock);
+    return ret;
+}
+static DbRef *
+LMDBCreate(Db *d, Array *k)
+{
+    LMDB *db = (LMDB *) d;
+    MDB_txn *transaction;
+    LMDBRef *ret = NULL;
+    MDB_val key, empty_json;
+    MDB_dbi dbi;
+    int code;
+    if (!d || !k)
+    {
+        return NULL;
+    }
+
+    pthread_mutex_lock(&d->lock);
+    key = LMDBTranslateKey(k);
+
+    /* create a txn */
+    if ((code = mdb_txn_begin(db->environ, NULL, 0, &transaction)) != 0)
+    {
+        /* Very bad! */
+        Log(LOG_ERR,
+            "%s: could not begin transaction: %s",
+            __func__, mdb_strerror(code)
+        );
+        pthread_mutex_unlock(&d->lock);
+        goto end;
+    }
+    /* apparently you need to give it a dbi */
+    if ((code = mdb_dbi_open(transaction, "db", MDB_CREATE, &dbi)) != 0)
+    {
+        Log(LOG_ERR,
+            "%s: could not get transaction dbi: %s",
+            __func__, mdb_strerror(code)
+        );
+        pthread_mutex_unlock(&d->lock);
+        goto end;
+
+    }
+
+    empty_json.mv_size = 2;
+    empty_json.mv_data = "{}";
+    /* put data in it */
+    code = mdb_put(transaction, dbi, &key, &empty_json, MDB_NOOVERWRITE);
+    if (code == MDB_KEYEXIST)
+    {
+        mdb_dbi_close(db->environ, dbi);
+        mdb_txn_abort(transaction);
+        goto end;
+    }
+    else if (code == MDB_MAP_FULL)
+    {
+        Log(LOG_ERR, "%s: db is full", __func__);
+        mdb_dbi_close(db->environ, dbi);
+        mdb_txn_abort(transaction);
+        goto end;
+    }
+    else if (code != 0)
+    {
+        Log(LOG_ERR, "%s: mdb_put failure: %s", __func__, mdb_strerror(code));
+        mdb_dbi_close(db->environ, dbi);
+        mdb_txn_abort(transaction);
+        goto end;
+    }
+
+    ret = Malloc(sizeof(*ret));
+    DbRefInit(d, (DbRef *) ret);
+    /* TODO: Timestamp */
+    {
+        size_t i;
+        ret->base.name = ArrayCreate();
+        for (i = 0; i < ArraySize(k); i++)
+        {
+            char *ent = ArrayGet(k, i);
+            StringArrayAppend(ret->base.name, ent);
+        }
+    }
+    ret->base.json = HashMapCreate();
+    ret->transaction = transaction;
+    ret->dbi = dbi;
+end:
+    LMDBKillKey(key);
+    return (DbRef *) ret;
+}
+
+
+/* Implementation functions */
+static void
+LMDBClose(Db *d)
+{
+    LMDB *db = (LMDB *) d;
+    if (!d)
+    {
+        return;
+    }
+
+    mdb_env_close(db->environ);
+}
+
 Db *
 DbOpenLMDB(char *dir, size_t size)
 {
     /* TODO */
+    MDB_env *env = NULL;
+    int code;
     LMDB *db;
     if (!dir || !size)
     {
         return NULL;
     }
 
-    db = Malloc(sizeof(*db));
-    DbInit(db);
+    /* Try initialising LMDB */
+    if ((code = mdb_env_create(&env)) != 0)
+    {
+        Log(LOG_ERR, 
+            "%s: could not create LMDB env: %s",
+            __func__, mdb_strerror(code)
+        );
+        return NULL;
+    }
+    if ((code = mdb_env_set_mapsize(env, size) != 0))
+    {
+        Log(LOG_ERR, 
+            "%s: could not set mapsize to %lu: %s",
+            __func__, (unsigned long) size, 
+            mdb_strerror(code)
+        );
+        mdb_env_close(env);
+        return NULL;
+    }
+    mdb_env_set_maxdbs(env, 4);
+    if ((code = mdb_env_open(env, dir, 0, 0644)) != 0)
+    {
+        Log(LOG_ERR, 
+            "%s: could not open LMDB env: %s",
+            __func__, mdb_strerror(code)
+        );
+        mdb_env_close(env);
+        return NULL;
+    }
 
-    (void) size;
-    (void) dir;
-    return db;
+
+    db = Malloc(sizeof(*db));
+    DbInit((Db *) db);
+    db->environ = env;
+
+    db->base.lockFunc = NULL;
+    db->base.create = LMDBCreate;
+    db->base.unlock = LMDBUnlock;
+    db->base.delete = NULL;
+    db->base.exists = NULL;
+    db->base.close = LMDBClose;
+    db->base.list = NULL;
+    
+    return (Db *) db;
 }
 
 #else
@@ -32,6 +272,9 @@ Db *
 DbOpenLMDB(char *dir, size_t size)
 {
     /* Unimplemented function */
+    Log(LOG_ERR, 
+        "LMDB support is not enabled. Please compile with --use-lmdb"
+    );
     (void) size;
     (void) dir;
     return NULL;