Added support in CInitOptions to pass logging/filter modules to VSLogger.

ports/libsimpleservo/capi/Cargo.toml

@@ -15,8 +15,8 @@ bench = false
 [dependencies]
 simpleservo = { path = "../api" }
 log = "0.4"
-env_logger = "0.6"
 lazy_static = "1"
+env_logger = "0.6"
 backtrace = "0.3"
 
 [target.'cfg(target_os = "windows")'.dependencies]

ports/libsimpleservo/capi/src/lib.rs

@@ -21,6 +21,7 @@ use std::ffi::{CStr, CString};
 use std::mem;
 use std::os::raw::{c_char, c_void};
 use std::panic::{self, UnwindSafe};
+use std::slice;
 use std::sync::RwLock;
 
 extern "C" fn default_panic_handler(msg: *const c_char) {
@@ -222,6 +223,8 @@ pub struct CInitOptions {
     pub density: f32,
     pub vr_pointer: *mut c_void,
     pub enable_subpixel_text_antialiasing: bool,
+    pub vslogger_mod_list: *const *const c_char,
+    pub vslogger_mod_size: u32,
 }
 
 /// The returned string is not freed. This will leak.
@@ -231,13 +234,22 @@ pub extern "C" fn servo_version() -> *const c_char {
 }
 
 #[cfg(target_os = "windows")]
-fn init_logger() {
+fn init_logger(modules: &[*const c_char]) {
+    use crate::vslogger::LOG_MODULE_FILTERS;
     use log::LevelFilter;
     use std::sync::Once;
     use vslogger::VSLogger;
 
     static LOGGER: VSLogger = VSLogger;
     static LOGGER_INIT: Once = Once::new();
+
+    if !modules.is_empty() {
+        *LOG_MODULE_FILTERS.lock().unwrap() = modules
+            .iter()
+            .map(|modules| unsafe { CStr::from_ptr(*modules).to_string_lossy().into_owned() })
+            .collect::<Vec<_>>();
+    }
+
     LOGGER_INIT.call_once(|| {
         log::set_logger(&LOGGER)
             .map(|_| log::set_max_level(LevelFilter::Debug))
@@ -246,7 +258,7 @@ fn init_logger() {
 }
 
 #[cfg(not(target_os = "windows"))]
-fn init_logger() {
+fn init_logger(_modules: &[*const c_char]) {
     crate::env_logger::init();
 }
 
@@ -258,7 +270,13 @@ unsafe fn init(
     wakeup: extern "C" fn(),
     callbacks: CHostCallbacks,
 ) {
-    init_logger();
+    let logger_modules = if opts.vslogger_mod_list.is_null() {
+        &[]
+    } else {
+        slice::from_raw_parts(opts.vslogger_mod_list, opts.vslogger_mod_size as usize)
+    };
+
+    init_logger(logger_modules);
 
     if let Err(reason) = redirect_stdout_stderr() {
         warn!("Error redirecting stdout/stderr: {}", reason);
@@ -310,7 +328,6 @@ pub extern "C" fn init_with_egl(
     callbacks: CHostCallbacks,
 ) {
     catch_any_panic(|| {
-        init_logger();
         let gl = gl_glue::egl::init().unwrap();
         unsafe {
             init(
@@ -333,7 +350,6 @@ pub extern "C" fn init_with_gl(
     callbacks: CHostCallbacks,
 ) {
     catch_any_panic(|| {
-        init_logger();
         let gl = gl_glue::gl::init().unwrap();
         unsafe { init(opts, gl, None, None, wakeup, callbacks) }
     });

ports/libsimpleservo/capi/src/vslogger.rs

@@ -3,6 +3,11 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use log::{self, Level, Metadata, Record};
+use std::sync::{Arc, Mutex};
+
+lazy_static! {
+    pub static ref LOG_MODULE_FILTERS: Arc<Mutex<Vec<String>>> = Arc::new(Mutex::new(vec![]));
+}
 
 extern "C" {
     fn OutputDebugStringA(s: *const u8);
@@ -12,7 +17,10 @@ pub struct VSLogger;
 
 impl log::Log for VSLogger {
     fn enabled(&self, metadata: &Metadata) -> bool {
-        metadata.level() <= Level::Warn
+        let modules = LOG_MODULE_FILTERS.lock().unwrap();
+        let is_module_enabled =
+            modules.contains(&String::from(metadata.target())) || modules.is_empty();
+        return metadata.level() <= Level::Warn && is_module_enabled;
     }
 
     fn log(&self, record: &Record) {

support/hololens/ServoApp/ServoControl/Servo.cpp

@@ -69,6 +69,28 @@ Servo::Servo(hstring url, GLsizei width, GLsizei height, float dpi,
   o.enable_subpixel_text_antialiasing = false;
   o.vr_pointer = NULL;
 
+  // 7 filter modules.
+  /* Sample list of servo modules to filter.
+  static char *pfilters[] = {
+	  "servo",
+	  "simpleservo", 
+	  "simpleservo::jniapi",
+	  "simpleservo::gl_glue::egl",
+	  // Show JS errors by default.
+	  "script::dom::bindings::error",
+	  // Show GL errors by default.
+	  "canvas::webgl_thread",
+	  "compositing::compositor",
+	  "constellation::constellation",
+  };
+  */
+
+  // Example Call when *pfilters[] is used:
+  // o.vslogger_mod_list = pfilters; // servo log modules
+  // o.vslogger_mod_size = sizeof(pfilters) / sizeof(pfilters[0]) -1; // Important: Number of modules in pfilters
+  o.vslogger_mod_list = NULL;
+  o.vslogger_mod_size = 0;
+
   sServo = this; // FIXME;
 
   capi::CHostCallbacks c;