Hi Zhenhua,
> Use two layers to cache server side response data to client.
> 1. A fixed-length ring buffer.
> 2. A list of free ring buffers and a list of empty full ring buffer.
>
> If current ring buffer is full, put it into full buffer list and fetch
> a free buffer frome free list.
> ---
> gatchat/gatserver.c | 106
> +++++++++++++++++++++++++++++++++++++++++++++++---- 1 files changed, 98
> insertions(+), 8 deletions(-)
>
> diff --git a/gatchat/gatserver.c b/gatchat/gatserver.c
> index bf7e847..6e76016 100644
> --- a/gatchat/gatserver.c
> +++ b/gatchat/gatserver.c
> @@ -32,6 +32,15 @@
> #include "ringbuffer.h"
> #include "gatserver.h"
>
> +#define MAX_BUFFER_NUM 5
> +#define READ_BUF_SIZE 4096
> +/* #define WRITE_SCHEDULER_DEBUG 1 */
> +#ifdef WRITE_SCHEDULER_DEBUG
> +#define WRITE_BUF_SIZE 4
> +#else
> +#define WRITE_BUF_SIZE 4096
> +#endif
> +
So I don't like this limitation, we should simply alloc a new buffer when we
run out of space.
> enum ParserState {
> PARSER_STATE_IDLE,
> PARSER_STATE_A,
> @@ -90,17 +99,50 @@ struct _GAtServer {
> struct v250_settings v250; /* V.250 command setting */
> GIOChannel *channel; /* Server IO */
> guint read_watch; /* GSource read id, 0 if none */
> + guint write_watch; /* GSource write id, 0 if none
> */
> guint read_so_far; /* Number of bytes processed */
> GAtDisconnectFunc user_disconnect; /* User disconnect func */
> gpointer user_disconnect_data; /* User disconnect data */
> GAtDebugFunc debugf; /* Debugging output function */
> gpointer debug_data; /* Data to pass to debug func */
> struct ring_buffer *read_buf; /* Current read buffer */
> + struct ring_buffer *write_buf; /* Current write buffer */
> + GSList *full_list; /* List of full ring buffer */
> + GSList *free_list; /* List of free ring buffer */
See above, we can really just maintain one list, the full list. The head and
tail pointers should be easily accessible (write new data out from the head,
put data on the tail.) Maintain at least one buffer in the list.
> guint max_read_attempts; /* Max reads per select */
> enum ParserState parser_state;
> gboolean destroyed; /* Re-entrancy guard */
> };
>
> +static void g_at_server_wakeup_writer(GAtServer *server);
> +
> +static gboolean alloc_free_list(GAtServer *server)
> +{
> + struct ring_buffer *buf;
> + guint i;
> +
> + for (i = 0; i < MAX_BUFFER_NUM; i++) {
> + buf = ring_buffer_new(WRITE_BUF_SIZE);
> + if (!buf)
> + return FALSE;
> +
> + server->free_list = g_slist_prepend(server->free_list, buf);
> + }
> +
> + return TRUE;
> +}
> +
> +static void send_common(GAtServer *server, const char *buf)
> +{
> + gsize avail = ring_buffer_avail(server->write_buf);
> + gsize len = strlen(buf);
This part is wrong, the data can actually be binary as well.
> +
> + if (avail >= len)
> + ring_buffer_write(server->write_buf, buf, len);
> +
> + g_at_server_wakeup_writer(server);
> +}
> +
> static void g_at_server_send_result(GAtServer *server, GAtServerResult
> result) {
> struct v250_settings v250 = server->v250;
> @@ -108,7 +150,6 @@ static void g_at_server_send_result(GAtServer *server,
> GAtServerResult result) char buf[1024];
> char t = v250.s3;
> char r = v250.s4;
> - gsize wbuf;
>
> if (v250.quiet)
> return;
> @@ -125,8 +166,7 @@ static void g_at_server_send_result(GAtServer *server,
> GAtServerResult result) g_at_util_debug_chat(FALSE, buf, strlen(buf),
> server->debugf, server->debug_data);
>
> - g_io_channel_write(server->channel, (char *) buf, strlen(buf),
> - &wbuf);
> + send_common(server, buf);
> }
>
> static inline gboolean is_at_command_prefix(const char c)
> @@ -432,12 +472,30 @@ static gboolean received_data(GIOChannel *channel,
> GIOCondition cond, return TRUE;
> }
>
> +static gboolean can_write_data(GIOChannel *channel, GIOCondition cond,
> + gpointer data)
> +{
> + return FALSE;
> +}
> +
> static void g_at_server_cleanup(GAtServer *server)
> {
> /* Cleanup all received data */
> ring_buffer_free(server->read_buf);
> server->read_buf = NULL;
>
> + /* Cleanup pending data to write */
> + ring_buffer_free(server->write_buf);
> + server->write_buf = NULL;
> +
> + if (server->full_list)
> + g_slist_foreach(server->full_list, (GFunc)ring_buffer_free,
> + NULL);
> +
> + if (server->free_list)
> + g_slist_foreach(server->free_list, (GFunc)ring_buffer_free,
> + NULL);
> +
> server->channel = NULL;
> }
>
> @@ -446,8 +504,6 @@ static void read_watcher_destroy_notify(GAtServer
> *server) g_at_server_cleanup(server);
> server->read_watch = 0;
>
> - server->channel = NULL;
> -
> if (server->user_disconnect)
> server->user_disconnect(server->user_disconnect_data);
>
> @@ -455,6 +511,23 @@ static void read_watcher_destroy_notify(GAtServer
> *server) g_free(server);
> }
>
> +static void write_watcher_destroy_notify(GAtServer *server)
> +{
> + server->write_watch = 0;
> +}
> +
> +static void g_at_server_wakeup_writer(GAtServer *server)
> +{
> + if (server->write_watch != 0)
> + return;
> +
> + server->write_watch = g_io_add_watch_full(server->channel,
> + G_PRIORITY_DEFAULT,
> + G_IO_OUT | G_IO_HUP | G_IO_ERR | G_IO_NVAL,
> + can_write_data, server,
> + (GDestroyNotify)write_watcher_destroy_notify);
> +}
> +
> static void v250_settings_create(struct v250_settings *v250)
> {
> v250->s3 = '\r';
> @@ -482,12 +555,19 @@ GAtServer *g_at_server_new(GIOChannel *io)
> server->ref_count = 1;
> v250_settings_create(&server->v250);
> server->channel = io;
> - server->read_buf = ring_buffer_new(4096);
> - server->max_read_attempts = 3;
> -
> + server->read_buf = ring_buffer_new(READ_BUF_SIZE);
> if (!server->read_buf)
> goto error;
>
> + server->write_buf = ring_buffer_new(WRITE_BUF_SIZE);
> + if (!server->write_buf)
> + goto error;
> +
> + if (!alloc_free_list(server))
> + goto error;
> +
> + server->max_read_attempts = 3;
> +
> if (!g_at_util_setup_io(server->channel, G_IO_FLAG_NONBLOCK))
> goto error;
>
> @@ -502,6 +582,13 @@ error:
> if (server->read_buf)
> ring_buffer_free(server->read_buf);
>
> + if (server->write_buf)
> + ring_buffer_free(server->write_buf);
> +
> + if (server->free_list)
> + g_slist_foreach(server->free_list, (GFunc)ring_buffer_free,
> + NULL);
> +
> if (server)
> g_free(server);
>
> @@ -552,6 +639,9 @@ gboolean g_at_server_shutdown(GAtServer *server)
> server->user_disconnect = NULL;
> server->user_disconnect_data = NULL;
>
> + if (server->write_watch)
> + g_source_remove(server->write_watch);
> +
> if (server->read_watch)
> g_source_remove(server->read_watch);
>
Regards,
-Denis
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