stream: remove chaos related to writeable streams

For some reason, we support writeable streams. (Only encoding uses that,
and the use of it looks messy enough that I want to replace it with FILE
or avio today.)

It's a chaos: most streams do not actually check the mode parameter like
they should. Simplify it, and let streams signal availability of write
mode by setting a flag in the stream info struct.

stream/stream.c

@@ -289,6 +289,13 @@ static int open_internal(const stream_info_t *sinfo, struct stream *underlying,
     s->path = talloc_strdup(s, path);
     s->source = underlying;
     s->allow_caching = true;
+    s->mode = flags & (STREAM_READ | STREAM_WRITE);
+
+    if ((s->mode & STREAM_WRITE) && !sinfo->can_write) {
+        MP_ERR(s, "No write access implemented.\n");
+        talloc_free(s);
+        return STREAM_ERROR;
+    }
 
     // Parse options
     if (sinfo->priv_size) {
@@ -306,8 +313,7 @@ static int open_internal(const stream_info_t *sinfo, struct stream *underlying,
         }
     }
 
-    s->mode = flags & (STREAM_READ | STREAM_WRITE);
-    int r = sinfo->open(s, s->mode);
+    int r = sinfo->open(s);
     if (r != STREAM_OK) {
         talloc_free(s);
         return r;

stream/stream.h

@@ -110,13 +110,14 @@ struct stream;
 typedef struct stream_info_st {
     const char *name;
     // opts is set from ->opts
-    int (*open)(struct stream *st, int mode);
+    int (*open)(struct stream *st);
     const char **protocols;
     int priv_size;
     const void *priv_defaults;
     const struct m_option *options;
     const char **url_options;
     bool stream_filter;
+    bool can_write;
 } stream_info_t;
 
 typedef struct stream {

stream/stream_avdevice.c

@@ -20,11 +20,8 @@
 
 #include "stream.h"
 
-static int open_f(stream_t *stream, int mode)
+static int open_f(stream_t *stream)
 {
-    if (mode != STREAM_READ)
-        return STREAM_ERROR;
-
     stream->type = STREAMTYPE_AVDEVICE;
     stream->demuxer = "lavf";
 

stream/stream_bluray.c

@@ -712,7 +712,7 @@ static void select_initial_angle(stream_t *s) {
     bd_free_title_info(info);
 }
 
-static int bluray_stream_open(stream_t *s, int mode)
+static int bluray_stream_open(stream_t *s)
 {
     struct bluray_priv_s *b = s->priv;
 

stream/stream_cdda.c

@@ -283,7 +283,7 @@ static int control(stream_t *stream, int cmd, void *arg)
     return STREAM_UNSUPPORTED;
 }
 
-static int open_cdda(stream_t *st, int m)
+static int open_cdda(stream_t *st)
 {
     cdda_priv *priv = st->priv;
     cdda_priv *p = priv;
@@ -292,10 +292,6 @@ static int open_cdda(stream_t *st, int m)
     cdrom_drive_t *cdd = NULL;
     int last_track;
 
-    if (m != STREAM_READ) {
-        return STREAM_UNSUPPORTED;
-    }
-
     if (!p->device) {
         if (cdrom_device)
             p->device = talloc_strdup(NULL, cdrom_device);

stream/stream_dvb.c

@@ -627,7 +627,7 @@ static int dvb_streaming_start(stream_t *stream, int tuner_type, char *progname)
 
 
 
-static int dvb_open(stream_t *stream, int mode)
+static int dvb_open(stream_t *stream)
 {
         // I don't force  the file format bacause, although it's almost always TS,
         // there are some providers that stream an IP multicast with M$ Mpeg4 inside
@@ -637,10 +637,6 @@ static int dvb_open(stream_t *stream, int mode)
         char *progname;
         int tuner_type = 0, i;
 
-
-        if(mode != STREAM_READ)
-                return STREAM_UNSUPPORTED;
-
         priv->fe_fd = priv->sec_fd = priv->dvr_fd = -1;
         priv->config = dvb_get_config(stream);
         if(priv->config == NULL)

stream/stream_dvd.c

@@ -663,7 +663,7 @@ static int control(stream_t *stream,int cmd,void* arg)
 }
 
 
-static int open_s(stream_t *stream, int mode)
+static int open_s(stream_t *stream)
 {
   int k;
   dvd_priv_t *d = stream->priv;
@@ -932,7 +932,7 @@ fail:
   return STREAM_UNSUPPORTED;
 }
 
-static int ifo_stream_open (stream_t *stream, int mode)
+static int ifo_stream_open (stream_t *stream)
 {
     char* filename;
     dvd_priv_t *priv = talloc_ptrtype(stream, priv);
@@ -963,7 +963,7 @@ static int ifo_stream_open (stream_t *stream, int mode)
     free(filename);
     stream->url=talloc_strdup(stream, "dvd://");
 
-    return open_s(stream, mode);
+    return open_s(stream);
 }
 
 const stream_info_t stream_info_dvd = {

stream/stream_dvdnav.c

@@ -664,7 +664,7 @@ static struct priv *new_dvdnav_stream(stream_t *stream, char *filename)
     return priv;
 }
 
-static int open_s(stream_t *stream, int mode)
+static int open_s(stream_t *stream)
 {
     struct priv *priv, *p;
     priv = p = stream->priv;

stream/stream_edl.c

@@ -3,11 +3,8 @@
 
 #include "stream.h"
 
-static int s_open (struct stream *stream, int mode)
+static int s_open (struct stream *stream)
 {
-    if (mode != STREAM_READ)
-        return STREAM_ERROR;
-
     stream->type = STREAMTYPE_EDL;
     stream->demuxer = "edl";
 

stream/stream_file.c

@@ -204,7 +204,7 @@ static bool check_stream_network(stream_t *stream)
 }
 #endif
 
-static int open_f(stream_t *stream, int mode)
+static int open_f(stream_t *stream)
 {
     int fd;
     struct priv *priv = talloc_ptrtype(stream, priv);
@@ -213,15 +213,8 @@ static int open_f(stream_t *stream, int mode)
     };
     stream->priv = priv;
 
-    int m = O_CLOEXEC;
-    if (mode == STREAM_READ)
-        m |= O_RDONLY;
-    else if (mode == STREAM_WRITE)
-        m |= O_RDWR | O_CREAT | O_TRUNC;
-    else {
-        MP_ERR(stream, "Unknown open mode %d\n", mode);
-        return STREAM_UNSUPPORTED;
-    }
+    bool write = stream->mode == STREAM_WRITE;
+    int m = O_CLOEXEC | (write ? O_RDWR | O_CREAT | O_TRUNC : O_RDONLY);
 
     char *filename = mp_file_url_to_filename(stream, bstr0(stream->url));
     if (filename) {
@@ -231,7 +224,7 @@ static int open_f(stream_t *stream, int mode)
     }
 
     if (!strcmp(filename, "-")) {
-        if (mode == STREAM_READ) {
+        if (!write) {
             MP_INFO(stream, "Reading from stdin...\n");
             fd = 0;
 #if HAVE_SETMODE
@@ -301,4 +294,5 @@ const stream_info_t stream_info_file = {
     .name = "file",
     .open = open_f,
     .protocols = (const char*[]){ "file", "", NULL },
+    .can_write = true,
 };

stream/stream_lavf.c

@@ -32,7 +32,7 @@
 #include "bstr/bstr.h"
 #include "talloc.h"
 
-static int open_f(stream_t *stream, int mode);
+static int open_f(stream_t *stream);
 static char **read_icy(stream_t *stream);
 
 static int fill_buffer(stream_t *s, char *buffer, int max_len)
@@ -113,7 +113,7 @@ static int control(stream_t *s, int cmd, void *arg)
         // avio doesn't seem to support this - emulate it by reopening
         close_f(s);
         s->priv = NULL;
-        return open_f(s, STREAM_READ);
+        return open_f(s);
     }
     }
     return STREAM_UNSUPPORTED;
@@ -127,10 +127,9 @@ static int interrupt_cb(void *ctx)
 
 static const char * const prefix[] = { "lavf://", "ffmpeg://" };
 
-static int open_f(stream_t *stream, int mode)
+static int open_f(stream_t *stream)
 {
     struct MPOpts *opts = stream->opts;
-    int flags = 0;
     AVIOContext *avio = NULL;
     int res = STREAM_ERROR;
     AVDictionary *dict = NULL;
@@ -139,15 +138,7 @@ static int open_f(stream_t *stream, int mode)
     stream->seek = NULL;
     stream->seekable = false;
 
-    if (mode == STREAM_READ)
-        flags = AVIO_FLAG_READ;
-    else if (mode == STREAM_WRITE)
-        flags = AVIO_FLAG_WRITE;
-    else {
-        MP_ERR(stream, "Unknown open mode %d\n", mode);
-        res = STREAM_UNSUPPORTED;
-        goto out;
-    }
+    int flags = stream->mode == STREAM_WRITE ? AVIO_FLAG_WRITE : AVIO_FLAG_READ;
 
     const char *filename = stream->url;
     if (!filename) {
@@ -330,4 +321,5 @@ const stream_info_t stream_info_ffmpeg = {
      "rtmpt", "rtmpte", "rtmpts", "srtp", "tcp", "udp", "tls", "unix", "sftp",
      "md5",
      NULL },
+  .can_write = true,
 };

stream/stream_memory.c

@@ -55,7 +55,7 @@ static int control(stream_t *s, int cmd, void *arg)
     return STREAM_UNSUPPORTED;
 }
 
-static int open_f(stream_t *stream, int mode)
+static int open_f(stream_t *stream)
 {
     stream->fill_buffer = fill_buffer;
     stream->seek = seek;

stream/stream_mf.c

@@ -29,7 +29,7 @@
 #include "stream.h"
 
 static int
-mf_stream_open (stream_t *stream, int mode)
+mf_stream_open (stream_t *stream)
 {
   stream->type = STREAMTYPE_MF;
   stream->demuxer = "mf";

stream/stream_null.c

@@ -25,14 +25,14 @@
 
 #include "stream.h"
 
-static int open_s(stream_t *stream,int mode)
+static int open_s(stream_t *stream)
 {
   return 1;
 }
 
-
 const stream_info_t stream_info_null = {
     .name = "null",
     .open = open_s,
     .protocols = (const char*[]){ "null", NULL },
+    .can_write = true,
 };

stream/stream_pvr.c

@@ -1510,15 +1510,12 @@ pvr_stream_read (stream_t *stream, char *buffer, int size)
 }
 
 static int
-pvr_stream_open (stream_t *stream, int mode)
+pvr_stream_open (stream_t *stream)
 {
   struct v4l2_capability vcap;
   struct v4l2_ext_controls ctrls;
   struct pvr_t *pvr = NULL;
 
-  if (mode != STREAM_READ)
-    return STREAM_UNSUPPORTED;
-
   pvr = pvr_init ();
   pvr->log = stream->log;
 

stream/stream_rar.c

@@ -86,7 +86,7 @@ static int rar_entry_control(stream_t *s, int cmd, void *arg)
     return STREAM_UNSUPPORTED;
 }
 
-static int rar_entry_open(stream_t *stream, int mode)
+static int rar_entry_open(stream_t *stream)
 {
     if (!strchr(stream->path, '|'))
         return STREAM_ERROR;
@@ -158,11 +158,8 @@ static void rar_filter_close(stream_t *s)
     free_stream(m);
 }
 
-static int rar_filter_open(stream_t *stream, int mode)
+static int rar_filter_open(stream_t *stream)
 {
-    if (mode != STREAM_READ)
-        return STREAM_UNSUPPORTED;
-
     struct stream *rar = stream->source;
     if (!rar)
         return STREAM_UNSUPPORTED;

stream/stream_smb.c

@@ -87,10 +87,9 @@ static void close_f(stream_t *s){
   smbc_close(p->fd);
 }
 
-static int open_f (stream_t *stream, int mode)
+static int open_f (stream_t *stream)
 {
   char *filename;
-  mode_t m = 0;
   int64_t len;
   int fd, err;
 
@@ -99,14 +98,7 @@ static int open_f (stream_t *stream, int mode)
 
   filename = stream->url;
 
-  if(mode == STREAM_READ)
-    m = O_RDONLY;
-  else if (mode == STREAM_WRITE) //who's gonna do that ?
-    m = O_RDWR|O_CREAT|O_TRUNC;
-  else {
-    MP_ERR(stream, "[smb] Unknown open mode %d\n", mode);
-    return STREAM_UNSUPPORTED;
-  }
+  mode_t m = stream->mode == STREAM_WRITE ? O_RDWR|O_CREAT|O_TRUNC : O_RDONLY;
 
   if(!filename) {
     MP_ERR(stream, "[smb] Bad url\n");
@@ -149,4 +141,5 @@ const stream_info_t stream_info_smb = {
     .name = "smb",
     .open = open_f,
     .protocols = (const char*[]){"smb", NULL},
+    .can_write = true, //who's gonna do that?
 };

stream/stream_tv.c

@@ -86,7 +86,7 @@ tv_stream_close (stream_t *stream)
 {
 }
 static int
-tv_stream_open (stream_t *stream, int mode)
+tv_stream_open (stream_t *stream)
 {
 
   stream->type = STREAMTYPE_TV;

stream/stream_vcd.c

@@ -78,7 +78,7 @@ static void close_s(stream_t *stream) {
   free(stream->priv);
 }
 
-static int open_s(stream_t *stream,int mode)
+static int open_s(stream_t *stream)
 {
   int ret,ret2,f,sect,tmp;
   mp_vcd_priv_t* vcd;
@@ -90,14 +90,6 @@ static int open_s(stream_t *stream,int mode)
   char device[20] = "\\\\.\\?:";
 #endif
 
-  if(mode != STREAM_READ
-#if defined(__MINGW32__) || defined(__CYGWIN__)
-      || GetVersion() > 0x80000000 // Win9x
-#endif
-      ) {
-    return STREAM_UNSUPPORTED;
-  }
-
   char *dev = stream->url;
   if (strncmp("vcd://", dev, 6) != 0)
     return STREAM_UNSUPPORTED;