refactor: remove unnecessary allocation in read operation

lib/webfuse/impl/operation/read.c

@@ -14,32 +14,28 @@
 // do not read chunks larger than 1 MByte
 #define WF_MAX_READ_LENGTH (1024 * 1024)
 
-char * wf_impl_fill_buffer(
-	char const * data,
+char * wf_impl_operation_read_transform(
+	char * data,
 	size_t data_size,
 	char const * format,
 	size_t count,
 	wf_status * status)
 {
 	*status = WF_GOOD;
-	char * buffer = malloc(count);
+	char * buffer = data;
 
 	if (0 < count)
 	{
 		if (0 == strcmp("identity", format))
 		{
-			if (count == data_size)
-			{
-				memcpy(buffer, data, count);
-			}
-			else
+			if (count != data_size)
 			{
 				*status = WF_BAD;
 			}			
 		}
 		else if (0 == strcmp("base64", format))
 		{
-			size_t result = wf_impl_base64_decode(data, data_size, (uint8_t *) buffer, count);
+			size_t result = wf_impl_base64_decode(data, data_size, (uint8_t *) data, count);
 			if (result != count)
 			{
 				*status = WF_BAD;
@@ -51,12 +47,6 @@ char * wf_impl_fill_buffer(
 		}
 	}
 
-	if (WF_GOOD != *status)
-	{
-		free(buffer);
-		buffer = NULL;
-	}
-
 	return buffer;
 }
 
@@ -80,12 +70,12 @@ void wf_impl_operation_read_finished(
         	(wf_impl_json_is_string(format_holder)) &&
             (wf_impl_json_is_int(count_holder)))
 		{
-			char const * const data = wf_impl_json_string_get(data_holder);
+			char * const data = (char*) wf_impl_json_string_get(data_holder);
 			size_t const data_size = wf_impl_json_string_size(data_holder);
 			char const * const format = wf_impl_json_string_get(format_holder);
 			length = (size_t) wf_impl_json_int_get(count_holder);
 
-			buffer = wf_impl_fill_buffer(data, data_size, format, length, &status);
+			buffer = wf_impl_operation_read_transform(data, data_size, format, length, &status);
 		}
 		else
 		{
@@ -101,9 +91,6 @@ void wf_impl_operation_read_finished(
 	{
    		fuse_reply_err(request, ENOENT);
 	}
-	
-    free(buffer);
-
 }
 
 void wf_impl_operation_read(

lib/webfuse/impl/operation/read.h

@@ -17,8 +17,8 @@ extern void wf_impl_operation_read(
 	fuse_ino_t ino, size_t size, off_t off,
 			struct fuse_file_info *fi);
 
-extern char * wf_impl_fill_buffer(
-	char const * data,
+extern char * wf_impl_operation_read_transform(
+	char * data,
 	size_t data_size,
 	char const * format,
 	size_t count,

test/webfuse/operation/test_read.cc

@@ -84,53 +84,52 @@ TEST(wf_impl_operation_read, fail_rpc_null)
 TEST(wf_impl_operation_read, fill_buffer_identity)
 {
     wf_status status;
-    char * buffer = wf_impl_fill_buffer("brummni", 8, "identity", 8, &status);
+    char text[] = "brummni";
+    char * buffer = wf_impl_operation_read_transform(text, 8, "identity", 8, &status);
     ASSERT_EQ(WF_GOOD, status);
     ASSERT_STREQ("brummni", buffer);
-    free(buffer);
 }
 
 TEST(wf_impl_operation_read, fill_buffer_identity_fail_inconsistent_size)
 {
     wf_status status;
-    char * buffer = wf_impl_fill_buffer("brummni", 8, "identity", 7, &status);
+    char text[] = "brummni";
+    wf_impl_operation_read_transform(text, 8, "identity", 7, &status);
     ASSERT_NE(WF_GOOD, status);
-    ASSERT_EQ(nullptr, buffer);
 }
 
 TEST(wf_impl_operation_read, fill_buffer_base64)
 {
     wf_status status;
-    char * buffer = wf_impl_fill_buffer("YnJ1bW1uaQ==", 12, "base64", 7, &status);    
+    char text[] = "YnJ1bW1uaQ==";
+    char * buffer = wf_impl_operation_read_transform(text, 12, "base64", 7, &status);    
 
     ASSERT_EQ(WF_GOOD, status);
     ASSERT_EQ(0, strncmp("brummni", buffer, 7));
-    free(buffer);
 }
 
 TEST(wf_impl_operation_read, fill_buffer_base64_fail_invalid_data)
 {
     wf_status status;
-    char * buffer = wf_impl_fill_buffer("YnJ1bW1uaQ=A", 12, "base64", 8, &status);    
+    char text[] = "YnJ1bW1uaQ=A";
+    wf_impl_operation_read_transform(text, 12, "base64", 8, &status);    
     ASSERT_NE(WF_GOOD, status);
-    ASSERT_EQ(nullptr, buffer);
 }
 
 TEST(wf_impl_operation_read, fill_buffer_empty)
 {
     wf_status status;
-    char * buffer = wf_impl_fill_buffer(nullptr, 0, "identity", 0, &status);    
+    wf_impl_operation_read_transform(nullptr, 0, "identity", 0, &status);    
 
     ASSERT_EQ(WF_GOOD, status);
-    free(buffer);
 }
 
 TEST(wf_impl_operation_read, fill_buffer_fail_invalid_format)
 {
     wf_status status;
-    char * buffer = wf_impl_fill_buffer("some data", 9, "unknown", 9, &status);    
+    char text[] = "some data";
+    wf_impl_operation_read_transform(text, 9, "unknown", 9, &status);    
     ASSERT_NE(WF_GOOD, status);
-    ASSERT_EQ(nullptr, buffer);
 }
 
 TEST(wf_impl_operation_read, finished)