Use log, env_logger crates for logging

Cargo.lock

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Cargo.toml

 name = "deltamap"
 version = "0.1.0"
 authors = ["Johannes Hofmann <mail@b-r-u.org>"]
+readme = "README.md"
+repository = "https://github.com/b-r-u/deltamap"
+homepage = "https://github.com/b-r-u/deltamap"
+description = """
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+"""
+license = "GPL-3.0"
 
 [dependencies]
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+env_logger = "0.5.0-rc.2"
 gl = "0.9"
 image = "0.18"
 linked-hash-map = "0.5.0"
+log = "0.4"
 osmpbf = "0.1"
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 servo-glutin = "0.13"

src/config.rs

     pub fn load() -> Result<Config, String> {
         if let Ok(xdg_dirs) = xdg::BaseDirectories::with_prefix("deltamap") {
             if let Some(config_path) = xdg_dirs.find_config_file("config.toml") {
-                println!("Load config from path {:?}", config_path);
+                info!("load config from path {:?}", config_path);
 
                 Config::from_toml_file(config_path)
             } else {
                 // try to write a default config file
                 if let Ok(path) = xdg_dirs.place_config_file("config.toml") {
                     if let Ok(mut file) = File::create(&path) {
-                        println!("write default config {:?}", &path);
-                        let _ = file.write_all(DEFAULT_CONFIG.as_bytes());
+                        if file.write_all(DEFAULT_CONFIG.as_bytes()).is_ok() {
+                            info!("write default config to {:?}", &path);
+                        }
                     }
                 }
 
                 Config::from_toml_str(DEFAULT_CONFIG)
             }
         } else {
+            info!("load default config");
             Config::from_toml_str(DEFAULT_CONFIG)
         }
     }

src/context.rs

 impl Context {
     pub fn from_window(window: &glutin::Window) -> Context {
         let gl = gl::Gl::load_with(|ptr| window.get_proc_address(ptr) as *const _);
+        let cx = Context {gl: gl};
 
-        Context {gl: gl}
+        info!("OpenGL version: {}", cx.gl_version());
+        debug!("MAX_TEXTURE_SIZE: {}", cx.max_texture_size());
+
+        cx
     }
 
     pub fn gl_version(&self) -> String {
             match self.gl.GetError() {
                 gl::NO_ERROR => break,
                 gl::INVALID_VALUE => {
-                    println!("{}:{}, invalid value error", file, line);
+                    error!("{}:{}, invalid value error", file, line);
                 },
                 gl::INVALID_ENUM => {
-                    println!("{}:{}, invalid enum error", file, line);
+                    error!("{}:{}, invalid enum error", file, line);
                 },
                 gl::INVALID_OPERATION => {
-                    println!("{}:{}, invalid operation error", file, line);
+                    error!("{}:{}, invalid operation error", file, line);
                 },
                 gl::INVALID_FRAMEBUFFER_OPERATION => {
-                    println!("{}:{}, invalid framebuffer operation error", file, line);
+                    error!("{}:{}, invalid framebuffer operation error", file, line);
                 },
                 gl::OUT_OF_MEMORY => {
-                    println!("{}:{}, out of memory error", file, line);
+                    error!("{}:{}, out of memory error", file, line);
                 },
                 x => {
-                    println!("{}:{}, unknown error {}", file, line, x);
+                    error!("{}:{}, unknown error {}", file, line, x);
                 },
             }
         }

src/main.rs

+#[macro_use]
 extern crate clap;
+extern crate env_logger;
 extern crate glutin;
 extern crate image;
 extern crate linked_hash_map;
+#[macro_use]
+extern crate log;
 extern crate reqwest;
 extern crate toml;
 extern crate xdg;
 use tile_source::TileSource;
 
 
-static VERSION: &'static str = "0.1.0";
-
-
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 enum Action {
     Nothing,
 }
 
 fn main() {
+    env_logger::init();
+
     let matches = clap::App::new("DeltaMap")
-        .version(VERSION)
-        .author("Johannes Hofmann <mail@b-r-u.org>")
-        .about("A map viewer")
+        .version(crate_version!())
+        .author(crate_authors!())
+        .about(crate_description!())
         .arg(Arg::with_name("config")
             .short("c")
             .long("config")

src/program.rs

         match cx.gl.GetError() {
             context::gl::NO_ERROR => (),
             context::gl::INVALID_VALUE => {
-                println!("invalid value");
+                error!("invalid value");
                 return;
             },
             context::gl::INVALID_OPERATION => {
-                println!("invalid operation");
+                error!("invalid operation");
                 return;
             },
             _ => {
-                println!("unknown error");
+                error!("unknown error");
                 return;
             }
         };
         error_log.set_len(error_log_size as usize);
 
         let msg = String::from_utf8(error_log).unwrap();
-        println!("{}", msg);
+        error!("{}", msg);
     }
 }
 
         error_log.set_len(error_log_size as usize);
 
         if let Ok(msg) = String::from_utf8(error_log) {
-            println!("{}", msg);
+            error!("{}", msg);
         }
     }
 }

src/tile_loader.rs

                             client_opt = Client::builder().build().ok();
                         }
 
+                        info!("thread {}, download {:?}", thread_id, request.url);
+
                         if let Some(Ok(mut response)) = client_opt.as_ref().map(|c| c.get(&request.url).send()) {
                             let mut buf: Vec<u8> = vec![];
                             if response.copy_to(&mut buf).is_ok() {
                         }
 
                         // failed not load tile
+                        info!("thread {}, fail {:?}", thread_id, request.url);
                         if result_tx.send((request.tile, None)).is_err() {
                             break;
                         }