4 files changed, 83 insertions, 9 deletions
diff --git a/Swiften/Base/Log.cpp b/Swiften/Base/Log.cpp
index 9b16531..abfd2bc 100644
--- a/Swiften/Base/Log.cpp
+++ b/Swiften/Base/Log.cpp
@@ -19,2 +19,3 @@ static Log::Severity logLevel = Log::warning;
 std::unique_ptr<FILE, Log::LogFileClose> Log::logfile;
+Log::Callback Log::logCallback;
 
@@ -28,3 +29,6 @@ Log::~Log() {
     // Using stdio for thread safety (POSIX file i/o calls are guaranteed to be atomic)
-    if (logfile) {
+    if (logCallback) {
+        logCallback(severity_, std::move(file_), line_, std::move(function_), stream.str());
+    }
+    else if (logfile) {
         fwrite(stream.str().c_str(), sizeof(char), stream.str().size(), logfile.get());
@@ -40,8 +44,16 @@ Log::~Log() {
 std::ostringstream& Log::getStream(
-        Severity /*severity*/,
-        const std::string& severityString,
-        const std::string& file,
+        Severity severity,
+        std::string severityString,
+        std::string file,
         int line,
-        const std::string& function) {
-    stream << "[" << severityString << "] " << file << ":" << line << " " << function << ": ";
+        std::string function) {
+    if (logCallback) {
+        severity_ = severity;
+        file_ = std::move(file);
+        line_ = line;
+        function_ = std::move(function);
+    }
+    else {
+        stream << "[" << severityString << "] " << file << ":" << line << " " << function << ": ";
+    }
     return stream;
@@ -63,2 +75,6 @@ void Log::setLogFile(const std::string& fileName) {
 
+void Log::setLogCallback(Callback callback) {
+    Log::logCallback = callback;
+}
+
 }
diff --git a/Swiften/Base/Log.h b/Swiften/Base/Log.h
index e3e04a5..255e478 100644
--- a/Swiften/Base/Log.h
+++ b/Swiften/Base/Log.h
@@ -9,2 +9,3 @@
 #include <cstdio>
+#include <functional>
 #include <memory>
@@ -20,2 +21,3 @@ namespace Swift {
             };
+            using Callback = std::function<void(Severity severity, std::string file, int line, std::string function, std::string message)>;
 
@@ -26,6 +28,6 @@ namespace Swift {
                     Severity severity,
-                    const std::string& severityString,
-                    const std::string& file,
+                    std::string severityString,
+                    std::string file,
                     int line,
-                    const std::string& function);
+                    std::string function);
 
@@ -34,2 +36,3 @@ namespace Swift {
             static void setLogFile(const std::string& fileName);
+            static void setLogCallback(Callback callback);
 
@@ -45,2 +48,7 @@ namespace Swift {
             static std::unique_ptr<FILE, LogFileClose> logfile;
+            static Callback logCallback;
+            Severity severity_;
+            std::string file_;
+            int line_;
+            std::string function_;
     };
diff --git a/Swiften/Base/UnitTest/LogTest.cpp b/Swiften/Base/UnitTest/LogTest.cpp
new file mode 100644
index 0000000..5d710db
--- /dev/null
+++ b/Swiften/Base/UnitTest/LogTest.cpp
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2019 Isode Limited.
+ * All rights reserved.
+ * See the COPYING file for more information.
+ */
+
+#include <vector>
+
+#include <boost/algorithm/string/predicate.hpp>
+
+#include <gtest/gtest.h>
+
+#include <Swiften/Base/Log.h>
+
+using namespace Swift;
+
+struct LogEntry {
+    LogEntry(Log::Severity severity, std::string file, int line, std::string function, std::string message) : severity(severity), file(std::move(file)), line(line), function(std::move(function)), message(std::move(message)) {}
+
+    Log::Severity severity;
+    std::string file;
+    int line;
+    std::string function;
+    std::string message;
+};
+
+// Helper class to set the logging callback.  Using this class to set it will ensure the
+// logCallback is reset to empty (its default state) after each test.
+class LogCallbackSetter {
+public:
+    LogCallbackSetter(Log::Callback callback) {
+        Log::setLogCallback(callback);
+    }
+    ~LogCallbackSetter() {
+        Log::setLogCallback({});
+    }
+};
+
+TEST(LogTest, testCallback) {
+    std::vector<LogEntry> logEntries;
+    LogCallbackSetter callbackSetter = {[&](Log::Severity severity, const std::string& file, int line, const std::string& function, const std::string& message) {
+        logEntries.emplace_back(severity, file, line, function, message);
+    }};
+
+    SWIFT_LOG(error) << "An error";
+    ASSERT_EQ(1, logEntries.size());
+    ASSERT_EQ(Log::error, logEntries[0].severity);
+    ASSERT_EQ("An error", logEntries[0].message);
+}
diff --git a/Swiften/SConscript b/Swiften/SConscript
index 5705113..7ea7355 100644
--- a/Swiften/SConscript
+++ b/Swiften/SConscript
@@ -385,2 +385,3 @@ if env["SCONS_STAGE"] == "build" :
             File("Base/UnitTest/IDGeneratorTest.cpp"),
+            File("Base/UnitTest/LogTest.cpp"),
             File("Base/UnitTest/LRUCacheTest.cpp"),