Add logdb to libbtc, a simple and save append only key value file sto…

…rage format

Makefile.am

@@ -23,7 +23,8 @@ include_HEADERS = include/btc/btc.h \
 	include/btc/cstr.h \
 	include/btc/script.h \
 	include/btc/aes.h \
-	include/btc/random.h
+	include/btc/random.h \
+	include/btc/logdb.h
 
 noinst_HEADERS = \
 	src/sha2.h \
@@ -51,7 +52,8 @@ libbtc_la_SOURCES = \
 	src/tx.c \
 	src/script.c \
 	src/ecc_key.c \
-	src/aes.c
+	src/aes.c \
+	src/logdb.c
 
 libbtc_la_CFLAGS = -I$(top_srcdir)/include
 libbtc_la_LIBADD = $(LIBSECP256K1)
@@ -75,7 +77,8 @@ tests_SOURCES = \
 	test/serialize_tests.c \
 	test/tx_tests.c \
 	test/eckey_tests.c \
-	test/aes_tests.c
+	test/aes_tests.c \
+	test/logdb_tests.c
 
 tests_CFLAGS = -I$(top_srcdir)/include
 tests_CPPFLAGS = -I$(top_srcdir)/src

include/btc/logdb.h

@@ -0,0 +1,151 @@
+/*
+
+ The MIT License (MIT)
+
+ Copyright (c) 2015 Jonas Schnelli
+
+ Permission is hereby granted, free of charge, to any person obtaining
+ a copy of this software and associated documentation files (the "Software"),
+ to deal in the Software without restriction, including without limitation
+ the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ and/or sell copies of the Software, and to permit persons to whom the
+ Software is furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included
+ in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
+ OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+
+
+/*
+ File Format
+ 
+ [4 bytes]          per file magic 0xF9, 0xAA, 0x03, 0xBA
+ [int32_t/4 bytes]  version number
+ [int32_t/4 bytes]  version flags
+ [varint]           *hashlength* = length of hash used in file (shorten sha256, max 32 bytes, 8 by default)
+ ---- records
+ [4 bytes]          static per record magic 0x88, 0x61, 0xAD, 0xFC
+ [hashlength]       partial sha256 hash of the record body
+ [body]
+   [1 byte]         record type (0 = write | 1 = erase)
+   [varint]         length of the key
+   [variable]       key data
+   [varint]         length of the value
+   [variable]       value data
+ [hashlength]       partial sha256 of *all data* up to this point in logdb
+ ---- more records
+*/
+
+#ifndef __LIBBTC_LOGDB_H__
+#define __LIBBTC_LOGDB_H__
+
+#include "btc.h"
+#include "hash.h"
+#include "sha2.h"
+#include "buffer.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stddef.h>
+
+/** record types */
+enum btc_logdb_record_type {
+    RECORD_TYPE_WRITE = 0,
+    RECORD_TYPE_ERASE = 1
+};
+
+/** error types */
+enum btc_logdb_error {
+    LOGDB_SUCCESS = 0,
+    LOGDB_ERROR_UNKNOWN,
+    LOGDB_ERROR_FOPEN_FAILED,
+    LOGDB_ERROR_WRONG_FILE_FORMAT,
+    LOGDB_ERROR_DATASTREAM_ERROR,
+    LOGDB_ERROR_CHECKSUM,
+};
+
+/** single key/value record */
+typedef struct btc_logdb_record {
+    cstring* key;
+    cstring* value;
+    struct btc_logdb_record* next;
+    struct btc_logdb_record* prev;
+    btc_bool written;
+    uint8_t mode;
+} btc_logdb_record;
+
+/** logdb handle */
+typedef struct btc_log_db {
+    FILE *file;
+    uint256 ctx_state;
+    btc_logdb_record *head;
+    SHA256_CTX hashctx;
+    uint8_t hashlen;
+    uint32_t version;
+    uint32_t support_flags;
+} btc_log_db;
+
+/////////// RECORD HANDLING
+//////////////////////////////////
+/** creates new logdb key/value record */
+LIBBTC_API btc_logdb_record* btc_logdb_record_new();
+
+/** free record including containing key/value data */
+LIBBTC_API void btc_logdb_record_free(btc_logdb_record* rec);
+
+/** sets key value (binary buffer copy) */
+LIBBTC_API void btc_logdb_record_set(btc_logdb_record* rec, struct buffer *key, struct buffer *val);
+
+/** copy database record */
+LIBBTC_API btc_logdb_record* btc_logdb_record_copy(btc_logdb_record* b_rec);
+
+/** serialize a record into a cstring */
+void btc_logdb_record_ser(btc_logdb_record* rec, cstring *buf);
+
+/////////// DB HANDLING
+//////////////////////////////////
+/** creates new logdb handle, sets default values */
+LIBBTC_API btc_log_db* btc_logdb_new();
+/** frees database and all in-memory records, closes file if open */
+LIBBTC_API void btc_logdb_free(btc_log_db* db);
+
+/** loads given file as database (memory mapping) */
+LIBBTC_API btc_bool btc_logdb_load(btc_log_db* handle, const char *file_path, btc_bool create, enum btc_logdb_error *error);
+
+/** flushes database: writes down new records */
+LIBBTC_API btc_bool btc_logdb_flush(btc_log_db* db);
+
+/** deletes record with key */
+LIBBTC_API void btc_logdb_delete(btc_log_db* db, struct buffer *key);
+
+/** appends record to the logdb */
+LIBBTC_API void btc_logdb_append(btc_log_db* db, struct buffer *key, struct buffer *value);
+
+/** find and get value from key */
+LIBBTC_API cstring * btc_logdb_get(btc_log_db* db, struct buffer *key);
+
+/** writes down single record, internal */
+void btc_logdb_write_record(btc_log_db* db, btc_logdb_record *rec);
+
+/** deserializes next logdb record from file */
+btc_bool btc_logdb_record_deser_from_file(btc_logdb_record* rec, btc_log_db *db, enum btc_logdb_error *error);
+
+/** remove records with given key (to keep memory clean) */
+btc_bool btc_logdb_remove_existing_records(btc_logdb_record *usehead, cstring *key);
+#ifdef __cplusplus
+}
+#endif
+
+#endif //__LIBBTC_LOGDB_H__