Make the logging system static

No initialization is needed anymore and we can use the logging functions
safely at any point of the code (threading is not handled though, so you
might get multiplexed messages if you log from two threads
simultaneously).

13 files changed, 33 insertions, 121 deletions

diff --git a/android/cpp/jni.cpp b/android/cpp/jni.cpp
index 1163c33b57..62e153e9b9 100644
--- a/android/cpp/jni.cpp
+++ b/android/cpp/jni.cpp
@@ -15,7 +15,6 @@
 #include <mbgl/android/jni.hpp>
 #include <mbgl/android/native_map_view.hpp>
 #include <mbgl/map/map.hpp>
-#include <mbgl/platform/android/log_android.hpp>
 #include <mbgl/platform/event.hpp>
 #include <mbgl/platform/log.hpp>
 #include <mbgl/storage/network_status.hpp>
@@ -827,8 +826,6 @@ jobject JNICALL nativeLatLngForPixel(JNIEnv *env, jobject obj, jlong nativeMapVi
 extern "C" {
 
 extern "C" JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved) {
-    mbgl::Log::Set<mbgl::AndroidLogBackend>();
-
     mbgl::Log::Debug(mbgl::Event::JNI, "JNI_OnLoad");
 
     JNIEnv *env = nullptr;
diff --git a/bin/render.cpp b/bin/render.cpp
index 71981b9d96..01f6929092 100644
--- a/bin/render.cpp
+++ b/bin/render.cpp
@@ -5,15 +5,10 @@
 
 #include <mbgl/platform/default/headless_view.hpp>
 #include <mbgl/platform/default/headless_display.hpp>
+#include <mbgl/platform/log.hpp>
 #include <mbgl/storage/default_file_source.hpp>
 #include <mbgl/storage/default/sqlite_cache.hpp>
 
-#if __APPLE__
-#include <mbgl/platform/darwin/log_nslog.hpp>
-#else
-#include <mbgl/platform/default/log_stderr.hpp>
-#endif
-
 #pragma GCC diagnostic push
 #ifndef __clang__
 #pragma GCC diagnostic ignored "-Wunused-local-typedefs"
@@ -71,13 +66,6 @@ int main(int argc, char *argv[]) {
 
     using namespace mbgl;
 
-
-#if __APPLE__
-    Log::Set<NSLogBackend>();
-#else
-    Log::Set<StderrLogBackend>();
-#endif
-
     mbgl::SQLiteCache cache(cache_file);
     mbgl::DefaultFileSource fileSource(&cache);
 
diff --git a/include/mbgl/platform/android/log_android.hpp b/include/mbgl/platform/android/log_android.hpp
deleted file mode 100644
index 94d90a9b36..0000000000
--- a/include/mbgl/platform/android/log_android.hpp
+++ /dev/null
@@ -1,24 +0,0 @@
-#ifndef MBGL_PLATFORM_ANDROID_LOG_ANDROID
-#define MBGL_PLATFORM_ANDROID_LOG_ANDROID
-
-#include <mbgl/platform/log.hpp>
-
-namespace mbgl {
-
-class AndroidLogBackend : public LogBackend {
-private:
-    int severityToPriority(EventSeverity severity);
-
-public:
-    inline ~AndroidLogBackend() = default;
-
-    void record(EventSeverity severity, Event event, const std::string &msg);
-    void record(EventSeverity severity, Event event, const char* format, ...);
-    void record(EventSeverity severity, Event event, int64_t code);
-    void record(EventSeverity severity, Event event, int64_t code, const std::string &msg);
-};
-
-
-}
-
-#endif
diff --git a/include/mbgl/platform/darwin/log_nslog.hpp b/include/mbgl/platform/darwin/log_nslog.hpp
deleted file mode 100644
index 5b2ed04114..0000000000
--- a/include/mbgl/platform/darwin/log_nslog.hpp
+++ /dev/null
@@ -1,18 +0,0 @@
-#ifndef MBGL_COMMON_NSLOG_LOG
-#define MBGL_COMMON_NSLOG_LOG
-
-#include <mbgl/platform/log.hpp>
-
-namespace mbgl {
-
-class NSLogBackend : public LogBackend {
-public:
-    inline ~NSLogBackend() = default;
-
-    void record(EventSeverity severity, Event event, int64_t code, const std::string &msg);
-};
-
-
-}
-
-#endif
diff --git a/include/mbgl/platform/default/log_stderr.hpp b/include/mbgl/platform/default/log_stderr.hpp
deleted file mode 100644
index e07357593d..0000000000
--- a/include/mbgl/platform/default/log_stderr.hpp
+++ /dev/null
@@ -1,18 +0,0 @@
-#ifndef MBGL_COMMON_STDERR_LOG
-#define MBGL_COMMON_STDERR_LOG
-
-#include <mbgl/platform/log.hpp>
-
-namespace mbgl {
-
-class StderrLogBackend : public LogBackend {
-public:
-    inline ~StderrLogBackend() = default;
-
-    void record(EventSeverity severity, Event event, int64_t code, const std::string &msg) override;
-};
-
-
-}
-
-#endif
diff --git a/include/mbgl/platform/log.hpp b/include/mbgl/platform/log.hpp
index e5431a07cb..e6b8f17b65 100644
--- a/include/mbgl/platform/log.hpp
+++ b/include/mbgl/platform/log.hpp
@@ -10,17 +10,6 @@
 
 namespace mbgl {
 
-class LogBackend {
-public:
-    virtual inline ~LogBackend() = default;
-
-    void record(EventSeverity severity, Event event, const std::string &msg);
-    void record(EventSeverity severity, Event event, const char* format, ...);
-    void record(EventSeverity severity, Event event, int64_t code);
-
-    virtual void record(EventSeverity severity, Event event, int64_t code, const std::string &msg) = 0;
-};
-
 class Log {
 private:
     template <typename T, size_t N>
@@ -54,20 +43,20 @@ public:
         if (!includes(severity, disabledEventSeverities) &&
             !includes(event, disabledEvents) &&
             !includes({ severity, event }, disabledEventPermutations)) {
-            if (Backend) {
-                Backend->record(severity, event, ::std::forward<Args>(args)...);
-            }
+                record(severity, event, ::std::forward<Args>(args)...);
         }
     }
 
-    template<typename T, typename ...Args>
-    static inline const T &Set(Args&& ...args) {
-        Backend = util::make_unique<T>(::std::forward<Args>(args)...);
-        return *reinterpret_cast<T *>(Backend.get());
-    }
-
 private:
-    static std::unique_ptr<LogBackend> Backend;
+    static void record(EventSeverity severity, Event event, const std::string &msg);
+    static void record(EventSeverity severity, Event event, const char* format, ...);
+    static void record(EventSeverity severity, Event event, int64_t code);
+    static void record(EventSeverity severity, Event event, int64_t code, const std::string &msg);
+
+    // This method is the data sink that must be implemented by each platform we
+    // support. It should ideally output the error message in a human readable
+    // format to the developer.
+    static void platformRecord(EventSeverity severity, Event event, int64_t code, const std::string &msg);
 };
 
 }
diff --git a/linux/main.cpp b/linux/main.cpp
index 6688905ea9..6a2be43d7c 100644
--- a/linux/main.cpp
+++ b/linux/main.cpp
@@ -1,9 +1,9 @@
 #include <mbgl/mbgl.hpp>
 #include <mbgl/util/uv.hpp>
+#include <mbgl/platform/log.hpp>
 #include <mbgl/platform/platform.hpp>
 #include <mbgl/platform/default/settings_json.hpp>
 #include <mbgl/platform/default/glfw_view.hpp>
-#include <mbgl/platform/default/log_stderr.hpp>
 #include <mbgl/storage/default_file_source.hpp>
 #include <mbgl/storage/default/sqlite_cache.hpp>
 
@@ -26,8 +26,6 @@ void quit_handler(int) {
 }
 
 int main(int argc, char *argv[]) {
-    mbgl::Log::Set<mbgl::StderrLogBackend>();
-
     int fullscreen_flag = 0;
     std::string style;
 
diff --git a/macosx/main.mm b/macosx/main.mm
index f59fbda6a8..087544f7c4 100644
--- a/macosx/main.mm
+++ b/macosx/main.mm
@@ -1,6 +1,6 @@
+#include <mbgl/platform/log.hpp>
 #include <mbgl/platform/platform.hpp>
 #include <mbgl/platform/darwin/settings_nsuserdefaults.hpp>
-#include <mbgl/platform/darwin/log_nslog.hpp>
 #include <mbgl/platform/darwin/Reachability.h>
 #include <mbgl/platform/default/glfw_view.hpp>
 #include <mbgl/storage/default_file_source.hpp>
@@ -101,8 +101,6 @@ const std::string &defaultCacheDatabase() {
 }
 
 int main() {
-    mbgl::Log::Set<mbgl::NSLogBackend>();
-
     GLFWView view;
 
     mbgl::SQLiteCache cache(defaultCacheDatabase());
diff --git a/platform/android/log_android.cpp b/platform/android/log_android.cpp
index e1bec3e0cb..9de8232bac 100644
--- a/platform/android/log_android.cpp
+++ b/platform/android/log_android.cpp
@@ -1,4 +1,4 @@
-#include <mbgl/platform/android/log_android.hpp>
+#include <mbgl/platform/log.hpp>
 
 #define __STDC_FORMAT_MACROS // NDK bug workaround: https://code.google.com/p/android/issues/detail?id=72349
 #include <cinttypes>
@@ -7,7 +7,9 @@
 
 namespace mbgl {
 
-int AndroidLogBackend::severityToPriority(EventSeverity severity) {
+namespace {
+
+int severityToPriority(EventSeverity severity) {
     switch(severity) {
     case EventSeverity::Debug:
         return ANDROID_LOG_DEBUG;
@@ -26,7 +28,9 @@ int AndroidLogBackend::severityToPriority(EventSeverity severity) {
     }
 }
 
-void AndroidLogBackend::record(EventSeverity severity, Event event, int64_t code, const std::string &msg) {
+} // namespace
+
+void Log::platformRecord(EventSeverity severity, Event event, int64_t code, const std::string &msg) {
     __android_log_print(severityToPriority(severity), EventClass(event).c_str(), "(%" PRId64 ") %s", code, msg.c_str());
 }
 
diff --git a/platform/darwin/log_nslog.mm b/platform/darwin/log_nslog.mm
index edcf41ebb2..5d53ed812f 100644
--- a/platform/darwin/log_nslog.mm
+++ b/platform/darwin/log_nslog.mm
@@ -1,11 +1,11 @@
-#include <mbgl/platform/darwin/log_nslog.hpp>
+#include <mbgl/platform/log.hpp>
 
 #import <Foundation/Foundation.h>
 
 namespace mbgl {
 
-void NSLogBackend::record(EventSeverity severity, Event event, int64_t code,
-                          const std::string &msg) {
+void Log::platformRecord(EventSeverity severity, Event event, int64_t code,
+                         const std::string &msg) {
     NSString *message =
         [[NSString alloc] initWithBytes:msg.data() length:msg.size() encoding:NSUTF8StringEncoding];
     NSLog(@"[%s] %s: (%lld) %@", EventSeverityClass(severity).c_str(), EventClass(event).c_str(),
diff --git a/platform/default/log_stderr.cpp b/platform/default/log_stderr.cpp
index 891bfd57f8..3305176d96 100644
--- a/platform/default/log_stderr.cpp
+++ b/platform/default/log_stderr.cpp
@@ -1,10 +1,10 @@
-#include <mbgl/platform/default/log_stderr.hpp>
+#include <mbgl/platform/log.hpp>
 
 #include <iostream>
 
 namespace mbgl {
 
-void StderrLogBackend::record(EventSeverity severity, Event event, int64_t code, const std::string &msg) {
+void Log::platformRecord(EventSeverity severity, Event event, int64_t code, const std::string &msg) {
     std::cerr << "[" << severity << "] " << event << ": (" << code << ") " << msg << std::endl;
 }
 
diff --git a/platform/ios/MGLMapView.mm b/platform/ios/MGLMapView.mm
index 1ab1afcbba..f60d3a05ff 100644
--- a/platform/ios/MGLMapView.mm
+++ b/platform/ios/MGLMapView.mm
@@ -1,6 +1,6 @@
 #import "MGLMapView.h"
 
-#import <mbgl/platform/darwin/log_nslog.hpp>
+#import <mbgl/platform/log.hpp>
 #import <mbgl/platform/gl.hpp>
 
 #import <GLKit/GLKit.h>
@@ -181,10 +181,6 @@ mbgl::DefaultFileSource *mbglFileSource = nullptr;
 
 - (BOOL)commonInit
 {
-    // set logging backend
-    //
-    mbgl::Log::Set<mbgl::NSLogBackend>();
-
     // create context
     //
     _context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
diff --git a/src/mbgl/platform/log.cpp b/src/mbgl/platform/log.cpp
index 71463dc2f9..4bbff8da5d 100644
--- a/src/mbgl/platform/log.cpp
+++ b/src/mbgl/platform/log.cpp
@@ -4,13 +4,11 @@
 
 namespace mbgl {
 
-std::unique_ptr<LogBackend> Log::Backend;
-
-void LogBackend::record(EventSeverity severity, Event event, const std::string &msg) {
+void Log::record(EventSeverity severity, Event event, const std::string &msg) {
     record(severity, event, -1, msg);
 }
 
-void LogBackend::record(EventSeverity severity, Event event, const char* format, ...) {
+void Log::record(EventSeverity severity, Event event, const char* format, ...) {
     va_list args;
     va_start(args, format);
     char msg[4096];
@@ -20,8 +18,12 @@ void LogBackend::record(EventSeverity severity, Event event, const char* format,
     record(severity, event, -1, msg);
 }
 
-void LogBackend::record(EventSeverity severity, Event event, int64_t code) {
+void Log::record(EventSeverity severity, Event event, int64_t code) {
     record(severity, event, code, std::string());
 }
 
+void Log::record(EventSeverity severity, Event event, int64_t code, const std::string &msg) {
+    platformRecord(severity, event, code, msg);
+}
+
 }