[FFmpeg-devel] [PATCH 3/3] lavd/v4l2: simplify return value checks

[Stephan Hilb]

---
 libavdevice/v4l2.c | 49 ++++++++++++++++++-------------------------------
 1 file changed, 18 insertions(+), 31 deletions(-)

diff --git a/libavdevice/v4l2.c b/libavdevice/v4l2.c
index 41ae3e8..2b11359 100644
--- a/libavdevice/v4l2.c
+++ b/libavdevice/v4l2.c
@@ -162,15 +162,14 @@ static int device_open(AVFormatContext *ctx)
 {
     struct v4l2_capability cap;
     int fd;
-    int res, err;
+    int err;
     int flags = O_RDWR;
 
     if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
         flags |= O_NONBLOCK;
     }
 
-    fd = v4l2_open(ctx->filename, flags, 0);
-    if (fd < 0) {
+    if ((fd = v4l2_open(ctx->filename, flags, 0)) < 0) {
         err = errno;
 
         av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",
@@ -179,8 +178,7 @@ static int device_open(AVFormatContext *ctx)
         return AVERROR(err);
     }
 
-    res = v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap);
-    if (res < 0) {
+    if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
         err = errno;
         av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
                strerror(err));
@@ -258,11 +256,9 @@ static int device_init(AVFormatContext *ctx, int *width, int *height,
 
 static int first_field(int fd)
 {
-    int res;
     v4l2_std_id std;
 
-    res = v4l2_ioctl(fd, VIDIOC_G_STD, &std);
-    if (res < 0) {
+    if (v4l2_ioctl(fd, VIDIOC_G_STD, &std) < 0) {
         return 0;
     }
     if (std & V4L2_STD_NTSC) {
@@ -382,7 +378,7 @@ static void list_formats(AVFormatContext *ctx, int fd, int type)
 
 static int mmap_init(AVFormatContext *ctx)
 {
-    int i, res;
+    int i;
     struct video_data *s = ctx->priv_data;
     struct v4l2_requestbuffers req = {
         .type   = V4L2_BUF_TYPE_VIDEO_CAPTURE,
@@ -390,8 +386,7 @@ static int mmap_init(AVFormatContext *ctx)
         .memory = V4L2_MEMORY_MMAP
     };
 
-    res = v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req);
-    if (res < 0) {
+    if (v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req) < 0) {
         if (errno == EINVAL) {
             av_log(ctx, AV_LOG_ERROR, "Device does not support mmap\n");
         } else {
@@ -423,8 +418,7 @@ static int mmap_init(AVFormatContext *ctx)
             .index  = i,
             .memory = V4L2_MEMORY_MMAP
         };
-        res = v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf);
-        if (res < 0) {
+        if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {
             av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n");
             return AVERROR(errno);
         }
@@ -453,7 +447,7 @@ static int mmap_init(AVFormatContext *ctx)
 static void mmap_release_buffer(AVPacket *pkt)
 {
     struct v4l2_buffer buf = { 0 };
-    int res, fd;
+    int fd;
     struct buff_data *buf_descriptor = pkt->priv;
 
     if (pkt->data == NULL)
@@ -465,8 +459,7 @@ static void mmap_release_buffer(AVPacket *pkt)
     fd = buf_descriptor->fd;
     av_free(buf_descriptor);
 
-    res = v4l2_ioctl(fd, VIDIOC_QBUF, &buf);
-    if (res < 0)
+    if (v4l2_ioctl(fd, VIDIOC_QBUF, &buf) < 0)
         av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
                strerror(errno));
 
@@ -516,11 +509,10 @@ static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)
 static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)
 {
     struct video_data *s = ctx->priv_data;
+    int res;
 
-    if (s->ts_mode) {
-        int r = init_convert_timestamp(ctx, *ts);
-        if (r < 0)
-            return r;
+    if (s->ts_mode && (res = init_convert_timestamp(ctx, *ts)) < 0) {
+        return res;
     }
 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
     if (s->timefilter) {
@@ -580,8 +572,7 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
     pkt->data= s->buf_start[buf.index];
     pkt->size = buf.bytesused;
     pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec;
-    res = convert_timestamp(ctx, &pkt->pts);
-    if (res < 0)
+    if ((res = convert_timestamp(ctx, &pkt->pts)) < 0)
         return res;
     pkt->destruct = mmap_release_buffer;
     buf_descriptor = av_malloc(sizeof(struct buff_data));
@@ -605,7 +596,7 @@ static int mmap_start(AVFormatContext *ctx)
 {
     struct video_data *s = ctx->priv_data;
     enum v4l2_buf_type type;
-    int i, res;
+    int i;
 
     for (i = 0; i < s->buffers; i++) {
         struct v4l2_buffer buf = {
@@ -614,8 +605,7 @@ static int mmap_start(AVFormatContext *ctx)
             .memory = V4L2_MEMORY_MMAP
         };
 
-        res = v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf);
-        if (res < 0) {
+        if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
             av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
                    strerror(errno));
 
@@ -624,8 +614,7 @@ static int mmap_start(AVFormatContext *ctx)
     }
 
     type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
-    res = v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type);
-    if (res < 0) {
+    if (v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type) < 0) {
         av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n",
                strerror(errno));
 
@@ -793,12 +782,10 @@ static int v4l2_read_header(AVFormatContext *s1)
     enum AVCodecID codec_id = AV_CODEC_ID_NONE;
     enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
 
-    st = avformat_new_stream(s1, NULL);
-    if (!st)
+    if (!(st = avformat_new_stream(s1, NULL)))
         return AVERROR(ENOMEM);
 
-    s->fd = device_open(s1);
-    if (s->fd < 0)
+    if ((s->fd = device_open(s1)) < 0)
         return s->fd;
 
     if (s->list_format) {
-- 
1.8.1