From 171b7097087460bc08e5f07adfa814352ff1b1f9 Mon Sep 17 00:00:00 2001
From: Spencer Russell <spencer.f.russell@gmail.com>
Date: Sat, 21 Dec 2013 18:48:36 -0500
Subject: [PATCH] basic audio callback synchronization is working

---
 deps/src/shim.c  | 50 ++++++++++++++++--------------------------------
 src/PortAudio.jl | 33 +++++++++++++++++++++-----------
 2 files changed, 39 insertions(+), 44 deletions(-)

diff --git a/deps/src/shim.c b/deps/src/shim.c
index ef2f0f3..dc92d57 100644
--- a/deps/src/shim.c
+++ b/deps/src/shim.c
@@ -1,29 +1,7 @@
 #include <portaudio.h>
 #include <semaphore.h>
-#include <julia/julia.h>
-#include <math.h>
 #include <stdio.h>
-
-// some defines we need to include until PR 4997 is merged
-STATIC_INLINE jl_function_t *jl_get_function(jl_module_t *m, const char *name)
-{
-    return  (jl_function_t*) jl_get_global(m, jl_symbol(name));
-}
-
-DLLEXPORT jl_value_t *jl_call2(jl_function_t *f, jl_value_t *a, jl_value_t *b)
-{
-    jl_value_t *v;
-    JL_TRY {
-        JL_GC_PUSH3(&f,&a,&b);
-        jl_value_t *args[2] = {a,b};
-        v = jl_apply(f, args, 2);
-        JL_GC_POP();
-    }
-    JL_CATCH {
-        v = NULL;
-    }
-    return v;
-}
+#include <unistd.h>
 
 static int paCallback(const void *inputBuffer, void *outputBuffer,
                           unsigned long framesPerBuffer,
@@ -32,12 +10,22 @@ static int paCallback(const void *inputBuffer, void *outputBuffer,
                           void *userData);
 
 static PaStream *AudioStream;
-static jl_value_t *JuliaRemote;
+static int JuliaPipeReadFD = 0;
+static int JuliaPipeWriteFD = 0;
 static sem_t CSemaphore;
 static void *OutData = NULL;
 static unsigned long OutFrames = 0;
-static jl_function_t *RemotePutFunc = NULL;
-static jl_value_t *RemotePutArg = NULL;
+
+
+int make_pipe(void)
+{
+    int pipefd[2];
+    pipe(pipefd);
+    JuliaPipeReadFD = pipefd[0];
+    JuliaPipeWriteFD = pipefd[1];
+    sem_init(&CSemaphore, 0, 0);
+    return JuliaPipeReadFD;
+}
 
 
 void wake_callback_thread(void *outData, unsigned int outFrames)
@@ -47,15 +35,10 @@ void wake_callback_thread(void *outData, unsigned int outFrames)
     sem_post(&CSemaphore);
 }
 
-PaError open_stream(unsigned int sampleRate, unsigned int bufSize,
-                    jl_value_t *jlRemote)
+PaError open_stream(unsigned int sampleRate, unsigned int bufSize)
 {
     PaError err;
 
-    JuliaRemote = jlRemote;
-    sem_init(&CSemaphore, 0, 0);
-    RemotePutFunc = jl_get_function(jl_base_module, "put");
-    RemotePutArg = jl_box_int32(0);
 
     err = Pa_OpenDefaultStream(&AudioStream,
             0,          /* no input channels */
@@ -114,6 +97,7 @@ static int paCallback(const void *inputBuffer, void *outputBuffer,
                            void *userData)
 {
     unsigned int i;
+    unsigned char fd_data = 0;
 
     sem_wait(&CSemaphore);
     for(i=0; i<framesPerBuffer; i++)
@@ -121,6 +105,6 @@ static int paCallback(const void *inputBuffer, void *outputBuffer,
         ((float *)outputBuffer)[i] = ((float *)OutData)[i];
     }
     // TODO: copy the input data somewhere
-    jl_call2(RemotePutFunc, JuliaRemote, RemotePutArg);
+    write(JuliaPipeWriteFD, &fd_data, 1);
     return 0;
 }
diff --git a/src/PortAudio.jl b/src/PortAudio.jl
index 81cd408..47e9dcc 100644
--- a/src/PortAudio.jl
+++ b/src/PortAudio.jl
@@ -13,15 +13,22 @@ const PA_NO_ERROR = 0
 ############ Exported Functions #############
 
 function play_sin(sample_rate, buf_size)
-    jl_remote = RemoteRef()
+    precompile(process!, (Array{Float32}, Array{Float32}))
 
-    ccall((:open_stream, libportaudio_shim), PaError,
-          (Cuint, Cuint, RemoteRef),
-          sample_rate, buf_size, jl_remote)
+    fd = ccall((:make_pipe, libportaudio_shim), Cint, ())
 
     info("Launching Audio Task...")
-    yieldto(Task(audio_task))
-    info("Audio Task Yielded")
+    function task_wrapper()
+        audio_task(fd)
+    end
+    schedule(Task(task_wrapper))
+    yield()
+    info("Audio Task Yielded, starting the stream...")
+
+    ccall((:open_stream, libportaudio_shim), PaError,
+          (Cuint, Cuint),
+          sample_rate, buf_size)
+    info("Portaudio stream started.")
 end
 
 #function stop_sin()
@@ -32,7 +39,7 @@ end
 ############ Internal Functions ############
 
 const sample_rate = 44100
-const buf_size = 512
+const buf_size = 1024
 const freq = 100
 phase = 0.0
 
@@ -54,10 +61,13 @@ function wake_callback_thread(out_array)
           out_array, size(out_array, 1))
 end
 
-function audio_task()
+function audio_task(jl_filedesc)
     info("Audio Task Launched")
-    in_array = zeros(buf_size)
-    out_array = zeros(buf_size)
+    in_array = convert(Array{Float32}, zeros(buf_size))
+    out_array = convert(Array{Float32}, zeros(buf_size))
+    desc_bytes = Cchar[0]
+    jl_stream = fdio(jl_filedesc)
+    jl_rawfd = RawFD(jl_filedesc)
     while true
         process!(out_array, in_array)
         # wake the C code so it knows we've given it some more data
@@ -65,7 +75,8 @@ function audio_task()
         # wait for new data to be available from the sound card (and for it to
         # have processed our last frame of data). At some point we should do
         # something with the data we get from the callback
-        take(jl_remote)
+        wait(jl_rawfd, readable=true)
+        ccall((:read, ""), Clong, (Cint, Ptr{Void}, Culong), jl_filedesc, desc_bytes, 1)
     end
 end