Add logging callback

src/core.rs

@@ -7,7 +7,7 @@ use std::borrow::Cow;
 use std::marker::PhantomData;
 use ffi;
 use ::tools::{to_cstr, from_cstr, from_cstr_ref};
-use ::libc::c_void;
+use ::libc::{c_void, c_char, c_int};
 use ::enums::*;
 
 /// Retrieve libvlc version. 
@@ -93,6 +93,15 @@ impl Instance {
             else { Some(ModuleDescriptionList{ptr: p}) }
         }
     }
+
+    /// Set logging callback
+    pub fn set_log<F: Fn(LogLevel, Log, Cow<str>) + Send + 'static>(&self, f: F) {
+        let cb: Box<Box<Fn(LogLevel, Log, Cow<str>) + Send + 'static>> = Box::new(Box::new(f));
+        
+        unsafe{
+            ffi::libvlc_log_set(self.ptr, logging_cb, Box::into_raw(cb) as *mut _);
+        }
+    }
 }
 
 impl Drop for Instance {
@@ -103,6 +112,21 @@ impl Drop for Instance {
     }
 }
 
+extern "C" {
+    fn vsnprintf(s: *mut c_char, n: usize, fmt: *const c_char, arg: ffi::va_list);
+}
+const BUF_SIZE: usize = 1024; // Write log message to the buffer by vsnprintf.
+unsafe extern "C" fn logging_cb(
+    data: *mut c_void, level: c_int, ctx: *const ffi::libvlc_log_t, fmt: *const c_char, args: ffi::va_list) {
+
+    let f: &Box<Fn(LogLevel, Log, Cow<str>) + Send + 'static> = ::std::mem::transmute(data);
+    let mut buf: [c_char; BUF_SIZE] = [0; BUF_SIZE];
+
+    vsnprintf(buf.as_mut_ptr(), BUF_SIZE, fmt, args);
+
+    f(::std::mem::transmute(level), Log{ptr: ctx}, from_cstr_ref(buf.as_ptr()).unwrap());
+}
+
 /// List of module description.
 pub struct ModuleDescriptionList {
     ptr: *mut ffi::libvlc_module_description_t,
@@ -464,3 +488,7 @@ pub struct VLCObject {
     _ptr: *mut c_void,
 }
 
+pub struct Log {
+    pub ptr: *const ffi::libvlc_log_t
+}
+

src/ffi.rs

@@ -32,6 +32,8 @@ pub enum libvlc_log_t {}
 pub enum vlc_log_t {}
 
 pub type libvlc_callback_t = unsafe extern "C" fn(*const libvlc_event_t, *mut c_void);
+pub type va_list = *mut c_void;
+pub type libvlc_log_cb = unsafe extern "C" fn(*mut c_void, c_int, *const libvlc_log_t, *const c_char, va_list);
 
 pub use LogLevel as libvlc_log_level;
 
@@ -77,7 +79,7 @@ extern "C" {
         ctx: *const libvlc_log_t, name: *const *const c_char,
         header: *const *const c_char, id: *mut uintptr_t);
     pub fn libvlc_log_unset(_: *mut libvlc_instance_t);
-    // pub fn libvlc_log_set
+    pub fn libvlc_log_set(instance: *mut libvlc_instance_t, cb: libvlc_log_cb, data: *mut c_void);
     pub fn libvlc_log_set_file(_: *mut libvlc_instance_t, stream: *mut FILE);
     pub fn libvlc_module_description_list_release(p_list: *mut libvlc_module_description_t);
     pub fn libvlc_audio_filter_list_get(