log support

Cargo.toml

@@ -4,6 +4,9 @@ version = "0.1.0"
 authors = ["lifning <lifning+git@pm.me>"]
 edition = "2018"
 
+[build-dependencies]
+cc = "^1"
+
 [dependencies]
 libretro-sys = "^0.1"
 failure = "^0.1"

build.rs

@@ -0,0 +1,6 @@
+
+fn main() {
+    cc::Build::new()
+        .file("src/retro/c_ext/log_wrapper.c")
+        .compile("log_wrapper");
+}

src/bin/example.rs

@@ -261,6 +261,10 @@ impl retro::wrapper::Handler for MyEmulator {
         self.av_info.geometry = geom;
         true
     }
+
+    fn log_print(&mut self, level: retro::ffi::LogLevel, msg: &str) {
+        eprint!("[{:?}] {}", level, msg);
+    }
 }
 
 

src/retro/c_ext/log_wrapper.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <stdarg.h>
+#include "libretro.h"
+
+typedef void (*rust_retro_ffi_log_print_t)(enum retro_log_level level, const char* msg);
+rust_retro_ffi_log_print_t g_rust_retro_ffi_log_print = NULL;
+
+void retro_log_snprintf_wrapper(enum retro_log_level level, const char* fmt, ...)
+{
+    if (g_rust_retro_ffi_log_print != NULL)
+    {
+        char msg[4096];
+
+        va_list args;
+        va_start(args, fmt);
+        vsnprintf(msg, sizeof(msg), fmt, args);
+        va_end(args);
+
+        g_rust_retro_ffi_log_print(level, msg);
+    }
+}
+
+bool c_ext_handle_get_log_interface(struct retro_log_callback* retro_cb)
+{
+    retro_cb->log = retro_log_snprintf_wrapper;
+    return true;
+}
+
+void c_ext_set_log_print_cb(rust_retro_ffi_log_print_t cb)
+{
+    g_rust_retro_ffi_log_print = cb;
+}

src/retro/wrapper.rs

@@ -2,7 +2,7 @@ use core::convert::TryInto;
 use core::ffi::c_void;
 use core::slice::from_raw_parts;
 
-use std::ffi::CString;
+use std::ffi::{CString, CStr};
 use std::os::raw::{c_uint, c_char};
 use std::path::{Path, PathBuf};
 use std::pin::Pin;
@@ -17,6 +17,19 @@ static mut CB_SINGLETON: StaticCallbacks = StaticCallbacks {
     handler: None,
 };
 
+pub type WrappedLogPrintFn = extern "C" fn(level: LogLevel, fmt: *const c_char);
+extern "C"  {
+    fn c_ext_handle_get_log_interface(cb: *mut LogCallback) -> bool;
+    fn c_ext_set_log_print_cb(cb: WrappedLogPrintFn);
+}
+extern "C" fn rust_retro_ffi_log_print(level: LogLevel, msg: *const c_char) {
+    unsafe {
+        if let Some(cb) = CB_SINGLETON.handler.as_mut() {
+            cb.log_print(level, CStr::from_ptr(msg).to_string_lossy().as_ref());
+        }
+    }
+}
+
 #[allow(unused)]
 pub trait Handler: Unpin + 'static {
     fn _delegate_handler(&self) -> Option<&mut dyn Handler> { None }
@@ -66,6 +79,9 @@ pub trait Handler: Unpin + 'static {
     fn get_username(&mut self) -> Option<String> { None }
     fn get_language(&mut self) -> Option<Language> { None }
     // fn set_serialization_quirks(&mut self, quirks: &mut u64) -> bool { false }
+
+    // -- environment-set callbacks (API extensions) --
+    fn log_print(&mut self, level: LogLevel, msg: &str) {}
 }
 
 #[derive(Default)]
@@ -123,7 +139,7 @@ impl StaticCallbacks {
             EnvCmd::GetInputDeviceCapabilities => Self::clone_into_void(data, &handler.get_input_device_capabilities()?)?,
             // TODO EnvCmd::GetSensorInterface => {},
             // TODO EnvCmd::GetCameraInterface => {},
-            // TODO EnvCmd::GetLogInterface => {},
+            EnvCmd::GetLogInterface => unsafe { c_ext_handle_get_log_interface(data as *mut LogCallback) },
             // TODO EnvCmd::GetPerfInterface => {},
             // TODO EnvCmd::GetLocationInterface => {},
             EnvCmd::GetCoreAssetsDirectory => Self::path_into_void(data, handler.get_core_assets_directory()?)?,
@@ -210,6 +226,7 @@ impl From<LibretroApi> for LibretroWrapper {
         api.set_audio_sample_batch(StaticCallbacks::audio_sample_batch_cb);
         api.set_input_poll(StaticCallbacks::input_poll_cb);
         api.set_input_state(StaticCallbacks::input_state_cb);
+        unsafe { c_ext_set_log_print_cb(rust_retro_ffi_log_print); }
         LibretroWrapper { api }
     }
 }