Implement a minimal GstCaps binding and use it in the demuxer

gst-plugin-flv/src/flvdemux.rs

@@ -29,6 +29,8 @@ use gst_plugin::adapter::*;
 use gst_plugin::utils;
 use gst_plugin::utils::Element;
 use gst_plugin::log::*;
+use gst_plugin::caps::Caps;
+use gst_plugin::caps;
 
 use slog::*;
 
@@ -134,29 +136,46 @@ impl AudioFormat {
     }
 
     fn to_string(&self) -> Option<String> {
-        let mut format = match self.format {
+        self.to_caps().map(|c| c.to_string())
+    }
+
+    fn to_caps(&self) -> Option<Caps> {
+        let mut caps = match self.format {
             flavors::SoundFormat::MP3 |
             flavors::SoundFormat::MP3_8KHZ => {
-                Some(String::from("audio/mpeg, mpegversion=(int) 1, layer=(int) 3"))
+                Some(Caps::new_simple("audio/mpeg",
+                                      vec![("mpegversion", &caps::Value::Int(1)),
+                                           ("layer", &caps::Value::Int(3))]))
             }
             flavors::SoundFormat::PCM_BE |
             flavors::SoundFormat::PCM_LE => {
                 if self.rate != 0 && self.channels != 0 {
                     // Assume little-endian for "PCM_NE", it's probably more common and we have no
                     // way to know what the endianness of the system creating the stream was
-                    Some(format!("audio/x-raw, layout=(string) interleaved, \
+                    Some(Caps::new_simple("audio/x-raw",
-                                          format=(string) {}",
+                                          vec![("layout",
-                                 if self.width == 8 { "U8" } else { "S16LE" }))
+                                                &caps::Value::String("interleaved".into())),
+                                               ("format",
+                                                &caps::Value::String(if self.width == 8 {
+                                                    "U8".into()
+                                                } else {
+                                                    "S16LE".into()
+                                                }))]))
                 } else {
                     None
                 }
             }
-            flavors::SoundFormat::ADPCM => Some(String::from("audio/x-adpcm, layout=(string) swf")),
+            flavors::SoundFormat::ADPCM => {
+                Some(Caps::new_simple("audio/x-adpcm",
+                                      vec![("layout", &caps::Value::String("swf".into()))]))
+            }
             flavors::SoundFormat::NELLYMOSER_16KHZ_MONO |
             flavors::SoundFormat::NELLYMOSER_8KHZ_MONO |
-            flavors::SoundFormat::NELLYMOSER => Some(String::from("audio/x-nellymoser")),
+            flavors::SoundFormat::NELLYMOSER => {
-            flavors::SoundFormat::PCM_ALAW => Some(String::from("audio/x-alaw")),
+                Some(Caps::new_simple("audio/x-nellymoser", vec![]))
-            flavors::SoundFormat::PCM_ULAW => Some(String::from("audio/x-mulaw")),
+            }
+            flavors::SoundFormat::PCM_ALAW => Some(Caps::new_simple("audio/x-alaw", vec![])),
+            flavors::SoundFormat::PCM_ULAW => Some(Caps::new_simple("audio/x-mulaw", vec![])),
             flavors::SoundFormat::AAC => {
                 // TODO: This requires getting the codec config from the stream
                 None
@@ -172,13 +191,15 @@ impl AudioFormat {
         };
 
         if self.rate != 0 {
-            format.as_mut().map(|f| f.push_str(&format!(", rate=(int) {}", self.rate)));
+            caps.as_mut()
+                .map(|c| c.set_simple(vec![("rate", &caps::Value::Int(self.rate as i32))]));
         }
         if self.channels != 0 {
-            format.as_mut().map(|f| f.push_str(&format!(", channels=(int) {}", self.channels)));
+            caps.as_mut()
+                .map(|c| c.set_simple(vec![("channels", &caps::Value::Int(self.channels as i32))]));
         }
 
-        format
+        caps
     }
 }
 
@@ -236,12 +257,19 @@ impl VideoFormat {
     }
 
     fn to_string(&self) -> Option<String> {
-        let mut format = match self.format {
+        self.to_caps().map(|caps| caps.to_string())
-            flavors::CodecId::H263 => Some(String::from("video/x-flash-video, flvversion=(int) 1")),
+    }
-            flavors::CodecId::SCREEN => Some(String::from("video/x-flash-screen")),
+
-            flavors::CodecId::VP6 => Some(String::from("video/x-vp6-flash")),
+    fn to_caps(&self) -> Option<Caps> {
-            flavors::CodecId::VP6A => Some(String::from("video/x-vp6-alpha")),
+        let mut caps = match self.format {
-            flavors::CodecId::SCREEN2 => Some(String::from("video/x-flash-screen2")),
+            flavors::CodecId::H263 => {
+                Some(Caps::new_simple("video/x-flash-video",
+                                      vec![("flvversion", &caps::Value::Int(1))]))
+            }
+            flavors::CodecId::SCREEN => Some(Caps::new_simple("video/x-flash-screen", vec![])),
+            flavors::CodecId::VP6 => Some(Caps::new_simple("video/x-vp6-flash", vec![])),
+            flavors::CodecId::VP6A => Some(Caps::new_simple("video/x-vp6-flash-alpha", vec![])),
+            flavors::CodecId::SCREEN2 => Some(Caps::new_simple("video/x-flash-screen2", vec![])),
             flavors::CodecId::H264 => {
                 // TODO: Need codec_data from the stream
                 None
@@ -253,26 +281,31 @@ impl VideoFormat {
         };
 
         if let (Some(width), Some(height)) = (self.width, self.height) {
-            format.as_mut()
+            caps.as_mut().map(|c| {
-                .map(|f| f.push_str(&format!(", width=(int) {}, height=(int) {}", width, height)));
+                c.set_simple(vec![("width", &caps::Value::Int(width as i32)),
+                                  ("height", &caps::Value::Int(height as i32))])
+            });
         }
 
         if let Some(par) = self.pixel_aspect_ratio {
             if par.0 != 0 && par.1 != 0 {
-                format.as_mut().map(|f| {
+                caps.as_mut().map(|c| {
-                    f.push_str(&format!(", pixel-aspect-ratio=(fraction) {}/{}", par.0, par.1))
+                    c.set_simple(vec![("pixel-aspect-ratio",
+                                       &caps::Value::Fraction(par.0 as i32, par.1 as i32))])
                 });
             }
         }
 
         if let Some(fps) = self.framerate {
             if fps.1 != 0 {
-                format.as_mut()
+                caps.as_mut().map(|c| {
-                    .map(|f| f.push_str(&format!(", framerate=(fraction) {}/{}", fps.0, fps.1)));
+                    c.set_simple(vec![("framerate",
+                                       &caps::Value::Fraction(fps.0 as i32, fps.1 as i32))])
+                });
             }
         }
 
-        format
+        caps
     }
 }
 
@@ -448,21 +481,17 @@ impl FlvDemux {
                     let mut streams = Vec::new();
 
                     if audio_changed {
-                        if let Some(format) = streaming_state.audio
+                        if let Some(caps) = streaming_state.audio
                             .as_ref()
-                            .and_then(|a| a.to_string()) {
+                            .and_then(|a| a.to_caps()) {
-                            streams.push(Stream::new(AUDIO_STREAM_ID,
+                            streams.push(Stream::new(AUDIO_STREAM_ID, caps, String::from("audio")));
-                                                         format,
-                                                         String::from("audio")));
                         }
                     }
                     if video_changed {
-                        if let Some(format) = streaming_state.video
+                        if let Some(caps) = streaming_state.video
                             .as_ref()
-                            .and_then(|v| v.to_string()) {
+                            .and_then(|v| v.to_caps()) {
-                            streams.push(Stream::new(VIDEO_STREAM_ID,
+                            streams.push(Stream::new(VIDEO_STREAM_ID, caps, String::from("video")));
-                                                         format,
-                                                         String::from("video")));
                         }
                     }
 
@@ -495,10 +524,10 @@ impl FlvDemux {
             debug!(logger, "Got new audio format: {:?}", new_audio_format);
             let new_stream = streaming_state.audio == None;
 
-            let format = new_audio_format.to_string();
+            let caps = new_audio_format.to_caps();
-            if let Some(format) = format {
+            if let Some(caps) = caps {
                 streaming_state.audio = Some(new_audio_format);
-                let stream = Stream::new(AUDIO_STREAM_ID, format, String::from("audio"));
+                let stream = Stream::new(AUDIO_STREAM_ID, caps, String::from("audio"));
                 if new_stream {
                     return Ok(HandleBufferResult::StreamAdded(stream));
                 } else {
@@ -564,10 +593,10 @@ impl FlvDemux {
 
             let new_stream = streaming_state.video == None;
 
-            let format = new_video_format.to_string();
+            let caps = new_video_format.to_caps();
-            if let Some(format) = format {
+            if let Some(caps) = caps {
                 streaming_state.video = Some(new_video_format);
-                let stream = Stream::new(VIDEO_STREAM_ID, format, String::from("video"));
+                let stream = Stream::new(VIDEO_STREAM_ID, caps, String::from("video"));
                 if new_stream {
                     return Ok(HandleBufferResult::StreamAdded(stream));
                 } else {

gst-plugin/src/caps.rs

@@ -0,0 +1,191 @@
+//  Copyright (C) 2016 Sebastian Dröge <sebastian@centricular.com>
+//
+//  This library is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU Library General Public
+//  License as published by the Free Software Foundation; either
+//  version 2 of the License, or (at your option) any later version.
+//
+//  This library is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//  Library General Public License for more details.
+//
+//  You should have received a copy of the GNU Library General Public
+//  License along with this library; if not, write to the
+//  Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+//  Boston, MA 02110-1301, USA.
+
+use libc::c_char;
+use std::os::raw::c_void;
+use std::ffi::CString;
+use std::ffi::CStr;
+use std::mem;
+use std::borrow::Cow;
+use std::fmt;
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Value<'a> {
+    Bool(bool),
+    Int(i32),
+    String(Cow<'a, str>),
+    Fraction(i32, i32),
+}
+
+pub struct Caps(*mut c_void);
+
+#[repr(C)]
+struct GValue {
+    typ: usize,
+    data: [u64; 2],
+}
+
+// See gtype.h
+const TYPE_BOOLEAN: usize = (5 << 2);
+const TYPE_INT: usize = (6 << 2);
+const TYPE_STRING: usize = (16 << 2);
+
+impl Caps {
+    pub fn new_simple(name: &str, values: Vec<(&str, &Value)>) -> Self {
+        extern "C" {
+            fn gst_caps_new_empty() -> *mut c_void;
+            fn gst_caps_append_structure(caps: *mut c_void, structure: *mut c_void);
+            fn gst_structure_new_empty(name: *const c_char) -> *mut c_void;
+        }
+
+        let mut caps = Caps(unsafe { gst_caps_new_empty() });
+
+        let name_cstr = CString::new(name).unwrap();
+        let structure = unsafe { gst_structure_new_empty(name_cstr.as_ptr()) };
+
+        unsafe {
+            gst_caps_append_structure(caps.0, structure);
+        }
+
+        caps.set_simple(values);
+
+        caps
+    }
+
+    pub fn set_simple(&mut self, values: Vec<(&str, &Value)>) {
+        extern "C" {
+            fn gst_caps_set_value(caps: *mut c_void, name: *const c_char, value: *const GValue);
+            fn g_value_init(value: *mut GValue, gtype: usize);
+            fn g_value_unset(value: *mut GValue);
+            fn g_value_set_boolean(value: *mut GValue, value: i32);
+            fn g_value_set_int(value: *mut GValue, value: i32);
+            fn g_value_set_string(value: *mut GValue, value: *const c_char);
+            fn gst_value_set_fraction(value: *mut GValue, value_n: i32, value_d: i32);
+            fn gst_fraction_get_type() -> usize;
+        }
+
+        for value in values {
+            let name_cstr = CString::new(value.0).unwrap();
+            let mut gvalue: GValue = unsafe { mem::zeroed() };
+
+            match value.1 {
+                &Value::Bool(v) => unsafe {
+                    g_value_init(&mut gvalue as *mut GValue, TYPE_BOOLEAN);
+                    g_value_set_boolean(&mut gvalue as *mut GValue, if v { 1 } else { 0 });
+                    gst_caps_set_value(self.0, name_cstr.as_ptr(), &mut gvalue as *mut GValue);
+                    g_value_unset(&mut gvalue as *mut GValue);
+                },
+                &Value::Int(v) => unsafe {
+                    g_value_init(&mut gvalue as *mut GValue, TYPE_INT);
+                    g_value_set_int(&mut gvalue as *mut GValue, v);
+                    gst_caps_set_value(self.0, name_cstr.as_ptr(), &mut gvalue as *mut GValue);
+                    g_value_unset(&mut gvalue as *mut GValue);
+                },
+                &Value::String(ref v) => unsafe {
+                    let v_cstr = CString::new(String::from((*v).clone())).unwrap();
+
+                    g_value_init(&mut gvalue as *mut GValue, TYPE_STRING);
+                    g_value_set_string(&mut gvalue as *mut GValue, v_cstr.as_ptr());
+                    gst_caps_set_value(self.0, name_cstr.as_ptr(), &mut gvalue as *mut GValue);
+                    g_value_unset(&mut gvalue as *mut GValue);
+                },
+                &Value::Fraction(v_n, v_d) => unsafe {
+                    g_value_init(&mut gvalue as *mut GValue, gst_fraction_get_type());
+                    gst_value_set_fraction(&mut gvalue as *mut GValue, v_n, v_d);
+                    gst_caps_set_value(self.0, name_cstr.as_ptr(), &mut gvalue as *mut GValue);
+                    g_value_unset(&mut gvalue as *mut GValue);
+                },
+            }
+        }
+    }
+
+    pub fn to_string(&self) -> String {
+        extern "C" {
+            fn gst_caps_to_string(caps: *mut c_void) -> *mut c_char;
+        }
+
+        unsafe { CStr::from_ptr(gst_caps_to_string(self.0)).to_string_lossy().into_owned() }
+    }
+
+    pub unsafe fn as_ptr(&self) -> *const c_void {
+        self.0
+    }
+
+    pub fn make_writable(self: Caps) -> Caps {
+        extern "C" {
+            fn gst_mini_object_make_writable(obj: *mut c_void) -> *mut c_void;
+        }
+
+        let raw = unsafe { gst_mini_object_make_writable(self.0) };
+
+        Caps(raw)
+    }
+
+    pub fn copy(&self) -> Caps {
+        extern "C" {
+            fn gst_mini_object_copy(obj: *const c_void) -> *mut c_void;
+        }
+        unsafe { Caps(gst_mini_object_copy(self.0)) }
+    }
+}
+
+impl Clone for Caps {
+    fn clone(&self) -> Self {
+        extern "C" {
+            fn gst_mini_object_ref(mini_object: *mut c_void) -> *mut c_void;
+        }
+
+        unsafe { Caps(gst_mini_object_ref(self.0)) }
+    }
+}
+
+impl fmt::Debug for Caps {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.write_str(&self.to_string())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::ptr;
+    use std::os::raw::c_void;
+
+    fn init() {
+        extern "C" {
+            fn gst_init(argc: *mut c_void, argv: *mut c_void);
+        }
+
+        unsafe {
+            gst_init(ptr::null_mut(), ptr::null_mut());
+        }
+    }
+
+    #[test]
+    fn test_simple() {
+        init();
+
+        let caps = Caps::new_simple("foo/bar",
+                                    vec![("int", &Value::Int(12)),
+                                         ("bool", &Value::Bool(true)),
+                                         ("string", &Value::String("bla".into())),
+                                         ("fraction", &Value::Fraction(1, 2))]);
+        assert_eq!(caps.to_string(),
+                   "foo/bar, int=(int)12, bool=(boolean)true, string=(string)bla, \
+                    fraction=(fraction)1/2");
+    }
+}

gst-plugin/src/demuxer.c

@@ -381,18 +381,18 @@ gst_rs_demuxer_loop (GstRsDemuxer * demuxer)
 
 void
 gst_rs_demuxer_add_stream (GstRsDemuxer * demuxer, guint32 index,
-    const gchar * format, const gchar * stream_id)
+    GstCaps * caps, const gchar * stream_id)
 {
   GstPad *pad;
   GstPadTemplate *templ;
-  GstCaps *caps;
   GstEvent *event;
   gchar *name, *full_stream_id;
 
   g_assert (demuxer->srcpads[index] == NULL);
 
-  GST_DEBUG_OBJECT (demuxer, "Adding stream %u with format %s and stream id %s",
+  GST_DEBUG_OBJECT (demuxer,
-      index, format, stream_id);
+      "Adding stream %u with format %" GST_PTR_FORMAT " and stream id %s",
+      index, caps, stream_id);
 
   templ =
       gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (demuxer),
@@ -414,9 +414,7 @@ gst_rs_demuxer_add_stream (GstRsDemuxer * demuxer, guint32 index,
   g_free (full_stream_id);
   gst_pad_push_event (pad, event);
 
-  caps = gst_caps_from_string (format);
   event = gst_event_new_caps (caps);
-  gst_caps_unref (caps);
   gst_pad_push_event (pad, event);
 
   event = gst_event_new_segment (&demuxer->segment);
@@ -438,18 +436,16 @@ gst_rs_demuxer_added_all_streams (GstRsDemuxer * demuxer)
 
 void
 gst_rs_demuxer_stream_format_changed (GstRsDemuxer * demuxer, guint32 index,
-    const gchar * format)
+    GstCaps * caps)
 {
-  GstCaps *caps;
   GstEvent *event;
 
   g_assert (demuxer->srcpads[index] != NULL);
 
-  GST_DEBUG_OBJECT (demuxer, "Format changed for stream %u: %s", index, format);
+  GST_DEBUG_OBJECT (demuxer, "Format changed for stream %u: %" GST_PTR_FORMAT,
+      index, caps);
 
-  caps = gst_caps_from_string (format);
   event = gst_event_new_caps (caps);
-  gst_caps_unref (caps);
 
   gst_pad_push_event (demuxer->srcpads[index], event);
 }

gst-plugin/src/demuxer.rs

@@ -33,6 +33,7 @@ use utils::*;
 use error::*;
 use buffer::*;
 use log::*;
+use caps::Caps;
 use plugin::Plugin;
 
 pub type StreamIndex = u32;
@@ -79,15 +80,15 @@ pub trait Demuxer {
 #[derive(Debug)]
 pub struct Stream {
     pub index: StreamIndex,
-    pub format: String,
+    pub caps: Caps,
     pub stream_id: String,
 }
 
 impl Stream {
-    pub fn new(index: StreamIndex, format: String, stream_id: String) -> Stream {
+    pub fn new(index: StreamIndex, caps: Caps, stream_id: String) -> Stream {
         Stream {
             index: index,
-            format: format,
+            caps: caps,
             stream_id: stream_id,
         }
     }
@@ -254,13 +255,13 @@ impl DemuxerWrapper {
             fn gst_rs_demuxer_stream_eos(raw: *mut c_void, index: u32);
             fn gst_rs_demuxer_add_stream(raw: *mut c_void,
                                          index: u32,
-                                         format: *const c_char,
+                                         caps: *const c_void,
                                          stream_id: *const c_char);
             fn gst_rs_demuxer_added_all_streams(raw: *mut c_void);
             // fn gst_rs_demuxer_remove_all_streams(raw: *mut c_void);
             fn gst_rs_demuxer_stream_format_changed(raw: *mut c_void,
                                                     index: u32,
-                                                    format: *const c_char);
+                                                    caps: *const c_void);
             fn gst_rs_demuxer_stream_push_buffer(raw: *mut c_void,
                                                  index: u32,
                                                  buffer: *mut c_void)
@@ -295,36 +296,29 @@ impl DemuxerWrapper {
                     return GstFlowReturn::Ok;
                 }
                 HandleBufferResult::StreamAdded(stream) => {
-                    let format_cstr = CString::new(stream.format.as_bytes()).unwrap();
                     let stream_id_cstr = CString::new(stream.stream_id.as_bytes()).unwrap();
 
                     unsafe {
                         gst_rs_demuxer_add_stream(self.raw,
                                                   stream.index,
-                                                  format_cstr.as_ptr(),
+                                                  stream.caps.as_ptr(),
                                                   stream_id_cstr.as_ptr());
                     }
                 }
                 HandleBufferResult::HaveAllStreams => unsafe {
                     gst_rs_demuxer_added_all_streams(self.raw);
                 },
-                HandleBufferResult::StreamChanged(stream) => {
+                HandleBufferResult::StreamChanged(stream) => unsafe {
-                    let format_cstr = CString::new(stream.format.as_bytes()).unwrap();
+                    gst_rs_demuxer_stream_format_changed(self.raw,
-
+                                                         stream.index,
-                    unsafe {
+                                                         stream.caps.as_ptr());
-                        gst_rs_demuxer_stream_format_changed(self.raw,
+                },
-                                                             stream.index,
-                                                             format_cstr.as_ptr());
-                    }
-                }
                 HandleBufferResult::StreamsChanged(streams) => {
                     for stream in streams {
-                        let format_cstr = CString::new(stream.format.as_bytes()).unwrap();
-
                         unsafe {
                             gst_rs_demuxer_stream_format_changed(self.raw,
                                                                  stream.index,
-                                                                 format_cstr.as_ptr());
+                                                                 stream.caps.as_ptr());
                         }
                     }
                 }

gst-plugin/src/lib.rs

@@ -37,3 +37,4 @@ pub mod source;
 pub mod sink;
 pub mod demuxer;
 pub mod log;
+pub mod caps;