refactor: load_file_into_buffer

runtime/src/module.c

@@ -217,17 +217,14 @@ err:
 }
 
 /**
- * Parses a JSON file and allocates one or more new modules
- * @param file_name The path of the JSON file
- * @return RC 0 on Success. -1 on Error
+ * Allocates a buffer in memory containing the entire contents of the file provided
+ * @param file_name file to load into memory
+ * @param ret_ptr Pointer to set with address of buffer this function allocates. The caller must free this!
+ * @return size of the allocated buffer or -1 in case of error;
  */
-int
-module_alloc_from_json(char *file_name)
+static inline size_t
+load_file_into_buffer(char *file_name, char **file_buffer)
 {
-	assert(file_name != NULL);
-	int       return_code = -1;
-	jsmntok_t tokens[JSON_MAX_ELEMENT_SIZE * JSON_MAX_ELEMENT_COUNT];
-
 	/* Use stat to get file attributes and make sure file is present and not empty */
 	struct stat stat_buffer;
 	if (stat(file_name, &stat_buffer) < 0) {
@@ -251,16 +248,16 @@ module_alloc_from_json(char *file_name)
 	}
 
 	/* Initialize a Buffer */
-	char *file_buffer = calloc(1, stat_buffer.st_size);
-	if (file_buffer == NULL) {
+	*file_buffer = calloc(1, stat_buffer.st_size);
+	if (*file_buffer == NULL) {
 		fprintf(stderr, "Attempt to allocate file buffer failed: %s\n", strerror(errno));
 		goto stat_buffer_alloc_err;
 	}
 
 	/* Read the file into the buffer and check that the buffer size equals the file size */
-	int total_chars_read = fread(file_buffer, sizeof(char), stat_buffer.st_size, module_file);
+	ssize_t total_chars_read = fread(*file_buffer, sizeof(char), stat_buffer.st_size, module_file);
 #ifdef LOG_MODULE_LOADING
-	debuglog("size read: %d content: %s\n", total_chars_read, file_buffer);
+	debuglog("size read: %d content: %s\n", total_chars_read, *file_buffer);
 #endif
 	if (total_chars_read != stat_buffer.st_size) {
 		fprintf(stderr, "Attempt to read %s into buffer failed: %s\n", file_name, strerror(errno));
@@ -275,6 +272,39 @@ module_alloc_from_json(char *file_name)
 	};
 	module_file = NULL;
 
+	return total_chars_read;
+
+fclose_err:
+	/* We will retry fclose when we fall through into stat_buffer_alloc_err */
+fread_err:
+	free(*file_buffer);
+stat_buffer_alloc_err:
+	// Check to ensure we haven't already close this
+	if (module_file != NULL) {
+		if (fclose(module_file) == EOF) panic("Failed to close file\n");
+	}
+err:
+	return (ssize_t)-1;
+}
+
+/**
+ * Parses a JSON file and allocates one or more new modules
+ * @param file_name The path of the JSON file
+ * @return RC 0 on Success. -1 on Error
+ */
+int
+module_alloc_from_json(char *file_name)
+{
+	assert(file_name != NULL);
+
+	int       return_code = -1;
+	jsmntok_t tokens[JSON_MAX_ELEMENT_SIZE * JSON_MAX_ELEMENT_COUNT];
+
+	/* Load file_name into memory */
+	char   *file_buffer      = NULL;
+	ssize_t total_chars_read = load_file_into_buffer(file_name, &file_buffer);
+	if (total_chars_read <= 0) goto module_alloc_err;
+
 	/* Initialize the Jasmine Parser and an array to hold the tokens */
 	jsmn_parser module_parser;
 	jsmn_init(&module_parser);
@@ -432,15 +462,8 @@ done:
 	return return_code;
 module_alloc_err:
 json_parse_err:
-fclose_err:
-	/* We will retry fclose when we fall through into stat_buffer_alloc_err */
-fread_err:
+file_load_err:
 	free(file_buffer);
-stat_buffer_alloc_err:
-	// Check to ensure we haven't already close this
-	if (module_file != NULL) {
-		if (fclose(module_file) == EOF) panic("Failed to close file\n");
-	}
 err:
 	return_code = -1;
 	goto done;