add data_writer_truncate/data_writer_clear

src/tkc/data_writer.c

@@ -20,6 +20,7 @@
  */
 
 #include "tkc/data_writer.h"
+#include "tkc/data_writer_factory.h"
 
 int32_t data_writer_write(data_writer_t* writer, uint64_t offset, const void* data, uint32_t size) {
   return_value_if_fail(writer != NULL && writer->vt != NULL && writer->vt->write != NULL, -1);
@@ -28,9 +29,28 @@ int32_t data_writer_write(data_writer_t* writer, uint64_t offset, const void* da
   return writer->vt->write(writer, offset, data, size);
 }
 
+ret_t data_writer_truncate(data_writer_t* writer, uint64_t size) {
+  return_value_if_fail(writer != NULL && writer->vt != NULL && writer->vt->truncate != NULL,
+                       RET_BAD_PARAMS);
+
+  return writer->vt->truncate(writer, size);
+}
+
 ret_t data_writer_destroy(data_writer_t* writer) {
   return_value_if_fail(writer != NULL && writer->vt != NULL && writer->vt->destroy != NULL,
                        RET_BAD_PARAMS);
 
   return writer->vt->destroy(writer);
 }
+
+ret_t data_writer_clear(const char* url) {
+  ret_t ret = RET_OK;
+  data_writer_t* writer = data_writer_factory_create_writer(data_writer_factory(), url);
+  return_value_if_fail(writer != NULL, RET_BAD_PARAMS);
+
+  ret = data_writer_truncate(writer, 0);
+  data_writer_destroy(writer);
+
+  return ret;
+}
+

src/tkc/data_writer.h

@@ -31,10 +31,12 @@ typedef struct _data_writer_t data_writer_t;
 
 typedef int32_t (*data_writer_write_t)(data_writer_t* writer, uint64_t offset, const void* data,
                                        uint32_t size);
+typedef ret_t (*data_writer_truncate_t)(data_writer_t* writer, uint64_t size);
 typedef ret_t (*data_writer_destroy_t)(data_writer_t* writer);
 
 typedef struct _data_writer_vtable_t {
   data_writer_write_t write;
+  data_writer_truncate_t truncate;
   data_writer_destroy_t destroy;
 } data_writer_vtable_t;
 
@@ -62,6 +64,16 @@ struct _data_writer_t {
  */
 int32_t data_writer_write(data_writer_t* writer, uint64_t offset, const void* data, uint32_t size);
 
+/**
+ * @method data_writer_truncate
+ * 截去指定长度之后的数据。
+ * @param {data_writer_t*} writer writer对象。
+ * @param {uint64_t} size 保留长度。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
+ret_t data_writer_truncate(data_writer_t* writer, uint64_t size);
+
 /**
  * @method data_writer_destroy
  * 销毁writer对象。
@@ -71,6 +83,15 @@ int32_t data_writer_write(data_writer_t* writer, uint64_t offset, const void* da
  */
 ret_t data_writer_destroy(data_writer_t* writer);
 
+/**
+ * @method data_writer_clear
+ * 清除指定URL的数据。
+ * @param {const char*} url URL。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
+ret_t data_writer_clear(const char* url);
+
 #define DATA_WRITER(writer) ((data_writer_t*)(writer))
 
 END_C_DECLS

src/tkc/data_writer_file.c

@@ -46,8 +46,15 @@ static ret_t data_writer_file_destroy(data_writer_t* writer) {
   return RET_OK;
 }
 
+static ret_t data_writer_file_truncate(data_writer_t* writer, uint64_t size) {
+  data_writer_file_t* file = (data_writer_file_t*)writer;
+
+  return fs_file_truncate(file->file, size);
+}
+
 static const data_writer_vtable_t s_data_writer_file_vtable = {
     .write = data_writer_file_write,
+    .truncate = data_writer_file_truncate,
     .destroy = data_writer_file_destroy,
 };