refactor: move api_buffer to web/buffer

include/villas/api.h

@@ -19,7 +19,6 @@ struct super_node;
 
 struct api;
 struct api_ressource;
-struct api_buffer;
 struct api_session;
 
 /** Callback type of command function
@@ -49,12 +48,6 @@ struct api {
 	struct super_node *super_node;
 };
 
-struct api_buffer {
-	char *buf;	/**< A pointer to the buffer. Usually resized via realloc() */
-	size_t size;	/**< The allocated size of the buffer. */
-	size_t len;	/**< The used length of the buffer. */
-};
-
 /** A connection via HTTP REST or WebSockets to issue API actions. */
 struct api_session {
 	enum api_mode mode;
@@ -102,12 +95,6 @@ int api_session_destroy(struct api_session *s);
 
 int api_session_run_command(struct api_session *s, json_t *req, json_t **resp);
 
-/** Send contents of buffer over libwebsockets connection */
-int api_buffer_send(struct api_buffer *b, struct lws *w, enum lws_write_protocol prot);
-
-/** Append received data to buffer. */
-int api_buffer_append(struct api_buffer *b, const char *in, size_t len);
-
 /** Libwebsockets callback for "api" endpoint */
 int api_ws_protocol_cb(struct lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len);
 

include/villas/web/buffer.h

@@ -0,0 +1,56 @@
+/** WebSocket buffer.
+ *
+ * @file
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
+ *********************************************************************************/
+
+#pragma once
+
+#include <stddef.h>
+
+#include <libwebsockets.h>
+
+#include "common.h"
+
+struct web_buffer {
+	char *buffer;	/**< A pointer to the buffer. Usually resized via realloc() */
+	size_t size;	/**< The allocated size of the buffer. */
+	size_t len;	/**< The used length of the buffer. */
+	size_t prefix;	/**< The used length of the buffer. */
+
+	enum lws_write_protocol protocol;
+	
+	enum state state;
+};
+
+/** Initialize a libwebsockets buffer. */
+int web_buffer_init(struct web_buffer *b, enum lws_write_protocol prot);
+
+/** Destroy a libwebsockets buffer. */
+int web_buffer_destroy(struct web_buffer *b);
+
+/** Flush the buffers contents to lws_write() */
+int web_buffer_write(struct web_buffer *b, struct lws *w);
+
+/** Copy \p len bytes from the beginning of the buffer and copy them to \p out.
+ *
+ * @param out The destination buffer. If NULL, we just remove \p len bytes from the buffer.
+ */
+int web_buffer_read(struct web_buffer *b, char *out, size_t len);
+
+/** Parse JSON from the beginning of the buffer.
+ *
+ * @retval -1 The buffer is empty.
+ * @retval -2 The buffer contains malformed JSON.
+ */
+int web_buffer_read_json(struct web_buffer *b, json_t **req);
+
+/** Append \p len bytes of \p in at the end of the buffer.
+ *
+ * The buffer is automatically resized.
+ */
+int web_buffer_append(struct web_buffer *b, const char *in, size_t len);
+
+/** Append the serialized represetnation of the JSON object \p res at the end of the buffer. */
+int web_buffer_append_json(struct web_buffer *b, json_t *res);

lib/api.c

@@ -11,46 +11,9 @@
 #include "log.h"
 #include "config.h"
 
-static int api_parse_request(struct api_buffer *b, json_t **req)
 {
-	json_error_t e;
-	
-	if (b->len <= 0)
-		return -1;
 
-	*req = json_loadb(b->buf, b->len, JSON_DISABLE_EOF_CHECK, &e);
-	if (!*req)
-		return -1;
 
-	if (e.position < b->len) {
-		void *dst = (void *) b->buf;
-		void *src = (void *) (b->buf + e.position);
-		
-		memmove(dst, src, b->len - e.position);
-		
-		b->len -= e.position;
-	}
-	else
-		b->len = 0;
-
-	return 1;
-}
-
-static int api_unparse_response(struct api_buffer *b, json_t *res)
-{
-	size_t len;
-
-retry:	len = json_dumpb(res, b->buf + b->len, b->size - b->len, 0);
-	if (len > b->size - b->len) {
-		b->buf = realloc(b->buf, b->len + len);
-		b->size += len;
-		goto retry;
-	}
-	else
-		b->len += len;
-	
-	return 0;
-}
 
 int api_session_run_command(struct api_session *s, json_t *json_in, json_t **json_out)
 {

lib/web/Makefile.inc

@@ -0,0 +1 @@
+LIB_SRCS += $(wildcard lib/web/*.c)

lib/web/buffer.c

@@ -0,0 +1,144 @@
+/** API buffer for sending and receiving data from libwebsockets.
+ *
+ * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
+ * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
+ *********************************************************************************/
+
+#include <jansson.h>
+
+#include "compat.h"
+#include "assert.h"
+#include "utils.h"
+#include "web/buffer.h"
+
+int web_buffer_init(struct web_buffer *b, enum lws_write_protocol prot)
+{
+	assert(b->state == STATE_DESTROYED);
+	
+	b->protocol = prot;
+	b->size = 0;
+	b->len = 0;
+	b->buffer = NULL;
+	b->prefix = b->protocol == LWS_WRITE_TEXT || b->protocol == LWS_WRITE_BINARY ? LWS_PRE : 0;
+	
+	b->state = STATE_INITIALIZED;
+
+	return 0;
+}
+
+int web_buffer_destroy(struct web_buffer *b)
+{
+	if (b->state == STATE_DESTROYED)
+		return 0;
+	
+	if (b->buffer)
+		free(b->buffer);
+	
+	b->state = STATE_DESTROYED;
+	
+	return 0;
+}
+
+int web_buffer_write(struct web_buffer *b, struct lws *w)
+{
+	int ret, len, sent = 0;
+	unsigned char *chunk;
+	
+	assert(b->state == STATE_INITIALIZED);
+	
+	if (b->len <= 0)
+		return 0;
+	
+	do {
+		chunk = (unsigned char *) b->buffer + b->prefix + sent;
+		len = strlen(b->buffer + b->prefix);
+
+		ret = lws_write(w, chunk, len, b->protocol);
+		if (ret < 0)
+			break;
+
+		sent += ret + 1;
+	} while (sent < b->len);
+
+	web_buffer_read(b, NULL, sent); /* drop sent bytes from the buffer*/
+	
+	return sent;
+}
+
+int web_buffer_read(struct web_buffer *b, char *out, size_t len)
+{
+	assert(b->state == STATE_INITIALIZED);
+
+	if (len > b->len)
+		len = b->len;
+
+	if (out)
+		memcpy(out, b->buffer + b->prefix, len);
+	
+	memmove(b->buffer + b->prefix, b->buffer + b->prefix + len, b->len - len);
+	b->len -= len;
+	
+	return 0;
+}
+
+int web_buffer_read_json(struct web_buffer *b, json_t **req)
+{
+	json_error_t e;
+
+	assert(b->state == STATE_INITIALIZED);
+
+	if (b->len <= 0)
+		return -1;
+
+	*req = json_loadb(b->buffer + b->prefix, b->len, JSON_DISABLE_EOF_CHECK, &e);
+	if (!*req)
+		return -2;
+	
+	web_buffer_read(b, NULL, e.position);
+
+	return 1;
+}
+
+int web_buffer_append(struct web_buffer *b, const char *in, size_t len)
+{
+	assert(b->state == STATE_INITIALIZED);
+	
+	/* We append a \0 to split messages */
+	len++;
+	
+	if (b->size < b->len + len) {
+		b->buffer = realloc(b->buffer, b->prefix + b->len + len);
+		if (!b->buffer)
+			return -1;
+		
+		b->size = b->len + len;
+	}
+	
+	memcpy(b->buffer + b->prefix + b->len, in, len);
+	b->len += len;
+	b->buffer[b->len+b->prefix] = 0;
+	
+	return 0;
+}
+
+int web_buffer_append_json(struct web_buffer *b, json_t *res)
+{
+	size_t len;
+
+	assert(b->state == STATE_INITIALIZED);
+
+retry:	len = json_dumpb(res, b->buffer + b->prefix + b->len, b->size - b->len, 0) + 1;
+	if (b->size < b->len + len) {
+		b->buffer = realloc(b->buffer, b->prefix + b->len + len);
+		if (!b->buffer)
+			return -1;
+		
+		b->size = b->len + len;
+		goto retry;
+	}
+
+	b->len += len;
+	b->buffer[b->len+b->prefix] = 0;
+
+	return 0;
+}