Merge pull request #972 from mapbox/log_cleanup

Refactoring of the log system

4 files changed, 21 insertions, 84 deletions

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 d40f963036..0000000000
--- a/include/mbgl/platform/darwin/log_nslog.hpp
+++ /dev/null
@@ -1,21 +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, 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/default/log_stderr.hpp b/include/mbgl/platform/default/log_stderr.hpp
deleted file mode 100644
index 45f76f0d1a..0000000000
--- a/include/mbgl/platform/default/log_stderr.hpp
+++ /dev/null
@@ -1,21 +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, 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/log.hpp b/include/mbgl/platform/log.hpp
index 8b58921bbe..de7f131714 100644
--- a/include/mbgl/platform/log.hpp
+++ b/include/mbgl/platform/log.hpp
@@ -10,16 +10,19 @@
 
 namespace mbgl {
 
-class LogBackend {
+class Log {
 public:
-    virtual inline ~LogBackend() = default;
-    virtual void record(EventSeverity severity, Event event, const std::string &msg) = 0;
-    virtual void record(EventSeverity severity, Event event, const char* format, ...) = 0;
-    virtual void record(EventSeverity severity, Event event, int64_t code) = 0;
-    virtual void record(EventSeverity severity, Event event, int64_t code, const std::string &msg) = 0;
-};
+    class Observer {
+    public:
+        virtual ~Observer() = default;
+
+        // When an observer is set, this function will be called for every log
+        // message. Returning true will consume the message.
+        virtual bool onRecord(EventSeverity severity, Event event, int64_t code, const std::string &msg) = 0;
+    };
+
+    static void setObserver(std::unique_ptr<Observer> Observer);
 
-class Log {
 private:
     template <typename T, size_t N>
     constexpr static bool includes(const T e, const T (&l)[N], const size_t i = 0) {
@@ -52,20 +55,20 @@ 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);
 };
 
 }