Merge pull request #607 from jroweboy/logging

Logging - Customizable backends

11 files changed, 334 insertions, 98 deletions

diff --git a/src/common/assert.h b/src/common/assert.h
index 3ee07f6a2..655446f34 100644
--- a/src/common/assert.h
+++ b/src/common/assert.h
@@ -30,15 +30,14 @@ __declspec(noinline, noreturn)
 #define ASSERT(_a_)                                                                                \
     do                                                                                             \
         if (!(_a_)) {                                                                              \
-            assert_noinline_call([] { NGLOG_CRITICAL(Debug, "Assertion Failed!"); });              \
+            assert_noinline_call([] { LOG_CRITICAL(Debug, "Assertion Failed!"); });                \
         }                                                                                          \
     while (0)
 
 #define ASSERT_MSG(_a_, ...)                                                                       \
     do                                                                                             \
         if (!(_a_)) {                                                                              \
-            assert_noinline_call(                                                                  \
-                [&] { NGLOG_CRITICAL(Debug, "Assertion Failed!\n" __VA_ARGS__); });                \
+            assert_noinline_call([&] { LOG_CRITICAL(Debug, "Assertion Failed!\n" __VA_ARGS__); }); \
         }                                                                                          \
     while (0)
 
diff --git a/src/common/common_paths.h b/src/common/common_paths.h
index 0a6132dab..d03fca314 100644
--- a/src/common/common_paths.h
+++ b/src/common/common_paths.h
@@ -32,12 +32,15 @@
 #define SDMC_DIR "sdmc"
 #define NAND_DIR "nand"
 #define SYSDATA_DIR "sysdata"
+#define LOG_DIR "log"
 
 // Filenames
 // Files in the directory returned by GetUserPath(D_CONFIG_IDX)
 #define EMU_CONFIG "emu.ini"
 #define DEBUGGER_CONFIG "debugger.ini"
 #define LOGGER_CONFIG "logger.ini"
+// Files in the directory returned by GetUserPath(D_LOGS_IDX)
+#define LOG_FILE "citra_log.txt"
 
 // Sys files
 #define SHARED_FONT "shared_font.bin"
diff --git a/src/common/file_util.cpp b/src/common/file_util.cpp
index 2d0b81c6e..b9e1fd1f6 100644
--- a/src/common/file_util.cpp
+++ b/src/common/file_util.cpp
@@ -118,7 +118,7 @@ bool IsDirectory(const std::string& filename) {
 #endif
 
     if (result < 0) {
-        NGLOG_DEBUG(Common_Filesystem, "stat failed on {}: {}", filename, GetLastErrorMsg());
+        LOG_DEBUG(Common_Filesystem, "stat failed on {}: {}", filename, GetLastErrorMsg());
         return false;
     }
 
@@ -128,29 +128,29 @@ bool IsDirectory(const std::string& filename) {
 // Deletes a given filename, return true on success
 // Doesn't supports deleting a directory
 bool Delete(const std::string& filename) {
-    NGLOG_TRACE(Common_Filesystem, "file {}", filename);
+    LOG_TRACE(Common_Filesystem, "file {}", filename);
 
     // Return true because we care about the file no
     // being there, not the actual delete.
     if (!Exists(filename)) {
-        NGLOG_DEBUG(Common_Filesystem, "{} does not exist", filename);
+        LOG_DEBUG(Common_Filesystem, "{} does not exist", filename);
         return true;
     }
 
     // We can't delete a directory
     if (IsDirectory(filename)) {
-        NGLOG_ERROR(Common_Filesystem, "Failed: {} is a directory", filename);
+        LOG_ERROR(Common_Filesystem, "Failed: {} is a directory", filename);
         return false;
     }
 
 #ifdef _WIN32
     if (!DeleteFileW(Common::UTF8ToUTF16W(filename).c_str())) {
-        NGLOG_ERROR(Common_Filesystem, "DeleteFile failed on {}: {}", filename, GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "DeleteFile failed on {}: {}", filename, GetLastErrorMsg());
         return false;
     }
 #else
     if (unlink(filename.c_str()) == -1) {
-        NGLOG_ERROR(Common_Filesystem, "unlink failed on {}: {}", filename, GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "unlink failed on {}: {}", filename, GetLastErrorMsg());
         return false;
     }
 #endif
@@ -160,16 +160,16 @@ bool Delete(const std::string& filename) {
 
 // Returns true if successful, or path already exists.
 bool CreateDir(const std::string& path) {
-    NGLOG_TRACE(Common_Filesystem, "directory {}", path);
+    LOG_TRACE(Common_Filesystem, "directory {}", path);
 #ifdef _WIN32
     if (::CreateDirectoryW(Common::UTF8ToUTF16W(path).c_str(), nullptr))
         return true;
     DWORD error = GetLastError();
     if (error == ERROR_ALREADY_EXISTS) {
-        NGLOG_DEBUG(Common_Filesystem, "CreateDirectory failed on {}: already exists", path);
+        LOG_DEBUG(Common_Filesystem, "CreateDirectory failed on {}: already exists", path);
         return true;
     }
-    NGLOG_ERROR(Common_Filesystem, "CreateDirectory failed on {}: {}", path, error);
+    LOG_ERROR(Common_Filesystem, "CreateDirectory failed on {}: {}", path, error);
     return false;
 #else
     if (mkdir(path.c_str(), 0755) == 0)
@@ -178,11 +178,11 @@ bool CreateDir(const std::string& path) {
     int err = errno;
 
     if (err == EEXIST) {
-        NGLOG_DEBUG(Common_Filesystem, "mkdir failed on {}: already exists", path);
+        LOG_DEBUG(Common_Filesystem, "mkdir failed on {}: already exists", path);
         return true;
     }
 
-    NGLOG_ERROR(Common_Filesystem, "mkdir failed on {}: {}", path, strerror(err));
+    LOG_ERROR(Common_Filesystem, "mkdir failed on {}: {}", path, strerror(err));
     return false;
 #endif
 }
@@ -190,10 +190,10 @@ bool CreateDir(const std::string& path) {
 // Creates the full path of fullPath returns true on success
 bool CreateFullPath(const std::string& fullPath) {
     int panicCounter = 100;
-    NGLOG_TRACE(Common_Filesystem, "path {}", fullPath);
+    LOG_TRACE(Common_Filesystem, "path {}", fullPath);
 
     if (FileUtil::Exists(fullPath)) {
-        NGLOG_DEBUG(Common_Filesystem, "path exists {}", fullPath);
+        LOG_DEBUG(Common_Filesystem, "path exists {}", fullPath);
         return true;
     }
 
@@ -209,14 +209,14 @@ bool CreateFullPath(const std::string& fullPath) {
         // Include the '/' so the first call is CreateDir("/") rather than CreateDir("")
         std::string const subPath(fullPath.substr(0, position + 1));
         if (!FileUtil::IsDirectory(subPath) && !FileUtil::CreateDir(subPath)) {
-            NGLOG_ERROR(Common, "CreateFullPath: directory creation failed");
+            LOG_ERROR(Common, "CreateFullPath: directory creation failed");
             return false;
         }
 
         // A safety check
         panicCounter--;
         if (panicCounter <= 0) {
-            NGLOG_ERROR(Common, "CreateFullPath: directory structure is too deep");
+            LOG_ERROR(Common, "CreateFullPath: directory structure is too deep");
             return false;
         }
         position++;
@@ -225,11 +225,11 @@ bool CreateFullPath(const std::string& fullPath) {
 
 // Deletes a directory filename, returns true on success
 bool DeleteDir(const std::string& filename) {
-    NGLOG_TRACE(Common_Filesystem, "directory {}", filename);
+    LOG_TRACE(Common_Filesystem, "directory {}", filename);
 
     // check if a directory
     if (!FileUtil::IsDirectory(filename)) {
-        NGLOG_ERROR(Common_Filesystem, "Not a directory {}", filename);
+        LOG_ERROR(Common_Filesystem, "Not a directory {}", filename);
         return false;
     }
 
@@ -240,14 +240,14 @@ bool DeleteDir(const std::string& filename) {
     if (rmdir(filename.c_str()) == 0)
         return true;
 #endif
-    NGLOG_ERROR(Common_Filesystem, "failed {}: {}", filename, GetLastErrorMsg());
+    LOG_ERROR(Common_Filesystem, "failed {}: {}", filename, GetLastErrorMsg());
 
     return false;
 }
 
 // renames file srcFilename to destFilename, returns true on success
 bool Rename(const std::string& srcFilename, const std::string& destFilename) {
-    NGLOG_TRACE(Common_Filesystem, "{} --> {}", srcFilename, destFilename);
+    LOG_TRACE(Common_Filesystem, "{} --> {}", srcFilename, destFilename);
 #ifdef _WIN32
     if (_wrename(Common::UTF8ToUTF16W(srcFilename).c_str(),
                  Common::UTF8ToUTF16W(destFilename).c_str()) == 0)
@@ -256,21 +256,21 @@ bool Rename(const std::string& srcFilename, const std::string& destFilename) {
     if (rename(srcFilename.c_str(), destFilename.c_str()) == 0)
         return true;
 #endif
-    NGLOG_ERROR(Common_Filesystem, "failed {} --> {}: {}", srcFilename, destFilename,
-                GetLastErrorMsg());
+    LOG_ERROR(Common_Filesystem, "failed {} --> {}: {}", srcFilename, destFilename,
+              GetLastErrorMsg());
     return false;
 }
 
 // copies file srcFilename to destFilename, returns true on success
 bool Copy(const std::string& srcFilename, const std::string& destFilename) {
-    NGLOG_TRACE(Common_Filesystem, "{} --> {}", srcFilename, destFilename);
+    LOG_TRACE(Common_Filesystem, "{} --> {}", srcFilename, destFilename);
 #ifdef _WIN32
     if (CopyFileW(Common::UTF8ToUTF16W(srcFilename).c_str(),
                   Common::UTF8ToUTF16W(destFilename).c_str(), FALSE))
         return true;
 
-    NGLOG_ERROR(Common_Filesystem, "failed {} --> {}: {}", srcFilename, destFilename,
-                GetLastErrorMsg());
+    LOG_ERROR(Common_Filesystem, "failed {} --> {}: {}", srcFilename, destFilename,
+              GetLastErrorMsg());
     return false;
 #else
 
@@ -282,8 +282,8 @@ bool Copy(const std::string& srcFilename, const std::string& destFilename) {
     // Open input file
     FILE* input = fopen(srcFilename.c_str(), "rb");
     if (!input) {
-        NGLOG_ERROR(Common_Filesystem, "opening input failed {} --> {}: {}", srcFilename,
-                    destFilename, GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "opening input failed {} --> {}: {}", srcFilename,
+                  destFilename, GetLastErrorMsg());
         return false;
     }
 
@@ -291,8 +291,8 @@ bool Copy(const std::string& srcFilename, const std::string& destFilename) {
     FILE* output = fopen(destFilename.c_str(), "wb");
     if (!output) {
         fclose(input);
-        NGLOG_ERROR(Common_Filesystem, "opening output failed {} --> {}: {}", srcFilename,
-                    destFilename, GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "opening output failed {} --> {}: {}", srcFilename,
+                  destFilename, GetLastErrorMsg());
         return false;
     }
 
@@ -302,8 +302,8 @@ bool Copy(const std::string& srcFilename, const std::string& destFilename) {
         size_t rnum = fread(buffer, sizeof(char), BSIZE, input);
         if (rnum != BSIZE) {
             if (ferror(input) != 0) {
-                NGLOG_ERROR(Common_Filesystem, "failed reading from source, {} --> {}: {}",
-                            srcFilename, destFilename, GetLastErrorMsg());
+                LOG_ERROR(Common_Filesystem, "failed reading from source, {} --> {}: {}",
+                          srcFilename, destFilename, GetLastErrorMsg());
                 goto bail;
             }
         }
@@ -311,8 +311,8 @@ bool Copy(const std::string& srcFilename, const std::string& destFilename) {
         // write output
         size_t wnum = fwrite(buffer, sizeof(char), rnum, output);
         if (wnum != rnum) {
-            NGLOG_ERROR(Common_Filesystem, "failed writing to output, {} --> {}: {}", srcFilename,
-                        destFilename, GetLastErrorMsg());
+            LOG_ERROR(Common_Filesystem, "failed writing to output, {} --> {}: {}", srcFilename,
+                      destFilename, GetLastErrorMsg());
             goto bail;
         }
     }
@@ -332,12 +332,12 @@ bail:
 // Returns the size of filename (64bit)
 u64 GetSize(const std::string& filename) {
     if (!Exists(filename)) {
-        NGLOG_ERROR(Common_Filesystem, "failed {}: No such file", filename);
+        LOG_ERROR(Common_Filesystem, "failed {}: No such file", filename);
         return 0;
     }
 
     if (IsDirectory(filename)) {
-        NGLOG_ERROR(Common_Filesystem, "failed {}: is a directory", filename);
+        LOG_ERROR(Common_Filesystem, "failed {}: is a directory", filename);
         return 0;
     }
 
@@ -348,11 +348,11 @@ u64 GetSize(const std::string& filename) {
     if (stat(filename.c_str(), &buf) == 0)
 #endif
     {
-        NGLOG_TRACE(Common_Filesystem, "{}: {}", filename, buf.st_size);
+        LOG_TRACE(Common_Filesystem, "{}: {}", filename, buf.st_size);
         return buf.st_size;
     }
 
-    NGLOG_ERROR(Common_Filesystem, "Stat failed {}: {}", filename, GetLastErrorMsg());
+    LOG_ERROR(Common_Filesystem, "Stat failed {}: {}", filename, GetLastErrorMsg());
     return 0;
 }
 
@@ -360,7 +360,7 @@ u64 GetSize(const std::string& filename) {
 u64 GetSize(const int fd) {
     struct stat buf;
     if (fstat(fd, &buf) != 0) {
-        NGLOG_ERROR(Common_Filesystem, "GetSize: stat failed {}: {}", fd, GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "GetSize: stat failed {}: {}", fd, GetLastErrorMsg());
         return 0;
     }
     return buf.st_size;
@@ -371,14 +371,12 @@ u64 GetSize(FILE* f) {
     // can't use off_t here because it can be 32-bit
     u64 pos = ftello(f);
     if (fseeko(f, 0, SEEK_END) != 0) {
-        NGLOG_ERROR(Common_Filesystem, "GetSize: seek failed {}: {}", fmt::ptr(f),
-                    GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "GetSize: seek failed {}: {}", fmt::ptr(f), GetLastErrorMsg());
         return 0;
     }
     u64 size = ftello(f);
     if ((size != pos) && (fseeko(f, pos, SEEK_SET) != 0)) {
-        NGLOG_ERROR(Common_Filesystem, "GetSize: seek failed {}: {}", fmt::ptr(f),
-                    GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "GetSize: seek failed {}: {}", fmt::ptr(f), GetLastErrorMsg());
         return 0;
     }
     return size;
@@ -386,10 +384,10 @@ u64 GetSize(FILE* f) {
 
 // creates an empty file filename, returns true on success
 bool CreateEmptyFile(const std::string& filename) {
-    NGLOG_TRACE(Common_Filesystem, "{}", filename);
+    LOG_TRACE(Common_Filesystem, "{}", filename);
 
     if (!FileUtil::IOFile(filename, "wb")) {
-        NGLOG_ERROR(Common_Filesystem, "failed {}: {}", filename, GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "failed {}: {}", filename, GetLastErrorMsg());
         return false;
     }
 
@@ -398,7 +396,7 @@ bool CreateEmptyFile(const std::string& filename) {
 
 bool ForeachDirectoryEntry(unsigned* num_entries_out, const std::string& directory,
                            DirectoryEntryCallable callback) {
-    NGLOG_TRACE(Common_Filesystem, "directory {}", directory);
+    LOG_TRACE(Common_Filesystem, "directory {}", directory);
 
     // How many files + directories we found
     unsigned found_entries = 0;
@@ -556,7 +554,7 @@ std::string GetCurrentDir() {
     char* dir;
     if (!(dir = getcwd(nullptr, 0))) {
 #endif
-        NGLOG_ERROR(Common_Filesystem, "GetCurrentDirectory failed: {}", GetLastErrorMsg());
+        LOG_ERROR(Common_Filesystem, "GetCurrentDirectory failed: {}", GetLastErrorMsg());
         return nullptr;
     }
 #ifdef _WIN32
@@ -676,7 +674,7 @@ std::string GetSysDirectory() {
 #endif
     sysDir += DIR_SEP;
 
-    NGLOG_DEBUG(Common_Filesystem, "Setting to {}:", sysDir);
+    LOG_DEBUG(Common_Filesystem, "Setting to {}:", sysDir);
     return sysDir;
 }
 
@@ -692,7 +690,7 @@ const std::string& GetUserPath(const unsigned int DirIDX, const std::string& new
         if (!FileUtil::IsDirectory(paths[D_USER_IDX])) {
             paths[D_USER_IDX] = AppDataRoamingDirectory() + DIR_SEP EMU_DATA_DIR DIR_SEP;
         } else {
-            NGLOG_INFO(Common_Filesystem, "Using the local user directory");
+            LOG_INFO(Common_Filesystem, "Using the local user directory");
         }
 
         paths[D_CONFIG_IDX] = paths[D_USER_IDX] + CONFIG_DIR DIR_SEP;
@@ -715,11 +713,13 @@ const std::string& GetUserPath(const unsigned int DirIDX, const std::string& new
         paths[D_SDMC_IDX] = paths[D_USER_IDX] + SDMC_DIR DIR_SEP;
         paths[D_NAND_IDX] = paths[D_USER_IDX] + NAND_DIR DIR_SEP;
         paths[D_SYSDATA_IDX] = paths[D_USER_IDX] + SYSDATA_DIR DIR_SEP;
+        // TODO: Put the logs in a better location for each OS
+        paths[D_LOGS_IDX] = paths[D_USER_IDX] + LOG_DIR DIR_SEP;
     }
 
     if (!newPath.empty()) {
         if (!FileUtil::IsDirectory(newPath)) {
-            NGLOG_ERROR(Common_Filesystem, "Invalid path specified {}", newPath);
+            LOG_ERROR(Common_Filesystem, "Invalid path specified {}", newPath);
             return paths[DirIDX];
         } else {
             paths[DirIDX] = newPath;
@@ -801,8 +801,8 @@ void SplitFilename83(const std::string& filename, std::array<char, 9>& short_nam
 
 IOFile::IOFile() {}
 
-IOFile::IOFile(const std::string& filename, const char openmode[]) {
-    Open(filename, openmode);
+IOFile::IOFile(const std::string& filename, const char openmode[], int flags) {
+    Open(filename, openmode, flags);
 }
 
 IOFile::~IOFile() {
@@ -823,11 +823,16 @@ void IOFile::Swap(IOFile& other) noexcept {
     std::swap(m_good, other.m_good);
 }
 
-bool IOFile::Open(const std::string& filename, const char openmode[]) {
+bool IOFile::Open(const std::string& filename, const char openmode[], int flags) {
     Close();
 #ifdef _WIN32
-    _wfopen_s(&m_file, Common::UTF8ToUTF16W(filename).c_str(),
-              Common::UTF8ToUTF16W(openmode).c_str());
+    if (flags != 0) {
+        m_file = _wfsopen(Common::UTF8ToUTF16W(filename).c_str(),
+                          Common::UTF8ToUTF16W(openmode).c_str(), flags);
+    } else {
+        _wfopen_s(&m_file, Common::UTF8ToUTF16W(filename).c_str(),
+                  Common::UTF8ToUTF16W(openmode).c_str());
+    }
 #else
     m_file = fopen(filename.c_str(), openmode);
 #endif
diff --git a/src/common/file_util.h b/src/common/file_util.h
index fc6b3ea46..5bc7fbf7c 100644
--- a/src/common/file_util.h
+++ b/src/common/file_util.h
@@ -156,7 +156,10 @@ void SplitFilename83(const std::string& filename, std::array<char, 9>& short_nam
 class IOFile : public NonCopyable {
 public:
     IOFile();
-    IOFile(const std::string& filename, const char openmode[]);
+    // flags is used for windows specific file open mode flags, which
+    // allows yuzu to open the logs in shared write mode, so that the file
+    // isn't considered "locked" while yuzu is open and people can open the log file and view it
+    IOFile(const std::string& filename, const char openmode[], int flags = 0);
 
     ~IOFile();
 
@@ -165,7 +168,7 @@ public:
 
     void Swap(IOFile& other) noexcept;
 
-    bool Open(const std::string& filename, const char openmode[]);
+    bool Open(const std::string& filename, const char openmode[], int flags = 0);
     bool Close();
 
     template <typename T>
@@ -220,6 +223,10 @@ public:
         return WriteArray(&object, 1);
     }
 
+    size_t WriteString(const std::string& str) {
+        return WriteArray(str.c_str(), str.length());
+    }
+
     bool IsOpen() const {
         return nullptr != m_file;
     }
diff --git a/src/common/logging/backend.cpp b/src/common/logging/backend.cpp
index c26b20062..242914c6a 100644
--- a/src/common/logging/backend.cpp
+++ b/src/common/logging/backend.cpp
@@ -2,16 +2,145 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
-#include <utility>
+#include <algorithm>
+#include <array>
+#include <chrono>
+#include <condition_variable>
+#include <memory>
+#include <thread>
+#ifdef _WIN32
+#include <share.h> // For _SH_DENYWR
+#else
+#define _SH_DENYWR 0
+#endif
 #include "common/assert.h"
+#include "common/common_funcs.h" // snprintf compatibility define
 #include "common/logging/backend.h"
-#include "common/logging/filter.h"
 #include "common/logging/log.h"
 #include "common/logging/text_formatter.h"
 #include "common/string_util.h"
+#include "common/threadsafe_queue.h"
 
 namespace Log {
 
+/**
+ * Static state as a singleton.
+ */
+class Impl {
+public:
+    static Impl& Instance() {
+        static Impl backend;
+        return backend;
+    }
+
+    Impl(Impl const&) = delete;
+    const Impl& operator=(Impl const&) = delete;
+
+    void PushEntry(Entry e) {
+        std::lock_guard<std::mutex> lock(message_mutex);
+        message_queue.Push(std::move(e));
+        message_cv.notify_one();
+    }
+
+    void AddBackend(std::unique_ptr<Backend> backend) {
+        std::lock_guard<std::mutex> lock(writing_mutex);
+        backends.push_back(std::move(backend));
+    }
+
+    void RemoveBackend(const std::string& backend_name) {
+        std::lock_guard<std::mutex> lock(writing_mutex);
+        auto it = std::remove_if(backends.begin(), backends.end(), [&backend_name](const auto& i) {
+            return !strcmp(i->GetName(), backend_name.c_str());
+        });
+        backends.erase(it, backends.end());
+    }
+
+    const Filter& GetGlobalFilter() const {
+        return filter;
+    }
+
+    void SetGlobalFilter(const Filter& f) {
+        filter = f;
+    }
+
+    Backend* GetBackend(const std::string& backend_name) {
+        auto it = std::find_if(backends.begin(), backends.end(), [&backend_name](const auto& i) {
+            return !strcmp(i->GetName(), backend_name.c_str());
+        });
+        if (it == backends.end())
+            return nullptr;
+        return it->get();
+    }
+
+private:
+    Impl() {
+        backend_thread = std::thread([&] {
+            Entry entry;
+            auto write_logs = [&](Entry& e) {
+                std::lock_guard<std::mutex> lock(writing_mutex);
+                for (const auto& backend : backends) {
+                    backend->Write(e);
+                }
+            };
+            while (true) {
+                std::unique_lock<std::mutex> lock(message_mutex);
+                message_cv.wait(lock, [&] { return !running || message_queue.Pop(entry); });
+                if (!running) {
+                    break;
+                }
+                write_logs(entry);
+            }
+            // Drain the logging queue. Only writes out up to MAX_LOGS_TO_WRITE to prevent a case
+            // where a system is repeatedly spamming logs even on close.
+            constexpr int MAX_LOGS_TO_WRITE = 100;
+            int logs_written = 0;
+            while (logs_written++ < MAX_LOGS_TO_WRITE && message_queue.Pop(entry)) {
+                write_logs(entry);
+            }
+        });
+    }
+
+    ~Impl() {
+        running = false;
+        message_cv.notify_one();
+        backend_thread.join();
+    }
+
+    std::atomic_bool running{true};
+    std::mutex message_mutex, writing_mutex;
+    std::condition_variable message_cv;
+    std::thread backend_thread;
+    std::vector<std::unique_ptr<Backend>> backends;
+    Common::MPSCQueue<Log::Entry> message_queue;
+    Filter filter;
+};
+
+void ConsoleBackend::Write(const Entry& entry) {
+    PrintMessage(entry);
+}
+
+void ColorConsoleBackend::Write(const Entry& entry) {
+    PrintColoredMessage(entry);
+}
+
+// _SH_DENYWR allows read only access to the file for other programs.
+// It is #defined to 0 on other platforms
+FileBackend::FileBackend(const std::string& filename)
+    : file(filename, "w", _SH_DENYWR), bytes_written(0) {}
+
+void FileBackend::Write(const Entry& entry) {
+    // prevent logs from going over the maximum size (in case its spamming and the user doesn't
+    // know)
+    constexpr size_t MAX_BYTES_WRITTEN = 50 * 1024L * 1024L;
+    if (!file.IsOpen() || bytes_written > MAX_BYTES_WRITTEN) {
+        return;
+    }
+    bytes_written += file.WriteString(FormatLogMessage(entry) + '\n');
+    if (entry.log_level >= Level::Error) {
+        file.Flush();
+    }
+}
+
 /// Macro listing all log classes. Code should define CLS and SUB as desired before invoking this.
 #define ALL_LOG_CLASSES()                                                                          \
     CLS(Log)                                                                                       \
@@ -125,20 +254,32 @@ Entry CreateEntry(Class log_class, Level log_level, const char* filename, unsign
     return entry;
 }
 
-static Filter* filter = nullptr;
+void SetGlobalFilter(const Filter& filter) {
+    Impl::Instance().SetGlobalFilter(filter);
+}
+
+void AddBackend(std::unique_ptr<Backend> backend) {
+    Impl::Instance().AddBackend(std::move(backend));
+}
 
-void SetFilter(Filter* new_filter) {
-    filter = new_filter;
+void RemoveBackend(const std::string& backend_name) {
+    Impl::Instance().RemoveBackend(backend_name);
+}
+
+Backend* GetBackend(const std::string& backend_name) {
+    return Impl::Instance().GetBackend(backend_name);
 }
 
 void FmtLogMessageImpl(Class log_class, Level log_level, const char* filename,
                        unsigned int line_num, const char* function, const char* format,
                        const fmt::format_args& args) {
-    if (filter && !filter->CheckMessage(log_class, log_level))
+    auto filter = Impl::Instance().GetGlobalFilter();
+    if (!filter.CheckMessage(log_class, log_level))
         return;
+
     Entry entry =
         CreateEntry(log_class, log_level, filename, line_num, function, fmt::vformat(format, args));
 
-    PrintColoredMessage(entry);
+    Impl::Instance().PushEntry(std::move(entry));
 }
-} // namespace Log
+} // namespace Log
\ No newline at end of file
diff --git a/src/common/logging/backend.h b/src/common/logging/backend.h
index 7e81efb23..57cdf6b2d 100644
--- a/src/common/logging/backend.h
+++ b/src/common/logging/backend.h
@@ -1,13 +1,15 @@
 // Copyright 2014 Citra Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
-
 #pragma once
 
 #include <chrono>
 #include <cstdarg>
+#include <memory>
 #include <string>
 #include <utility>
+#include "common/file_util.h"
+#include "common/logging/filter.h"
 #include "common/logging/log.h"
 
 namespace Log {
@@ -35,6 +37,80 @@ struct Entry {
 };
 
 /**
+ * Interface for logging backends. As loggers can be created and removed at runtime, this can be
+ * used by a frontend for adding a custom logging backend as needed
+ */
+class Backend {
+public:
+    virtual ~Backend() = default;
+    virtual void SetFilter(const Filter& new_filter) {
+        filter = new_filter;
+    }
+    virtual const char* GetName() const = 0;
+    virtual void Write(const Entry& entry) = 0;
+
+private:
+    Filter filter;
+};
+
+/**
+ * Backend that writes to stderr without any color commands
+ */
+class ConsoleBackend : public Backend {
+public:
+    static const char* Name() {
+        return "console";
+    }
+    const char* GetName() const override {
+        return Name();
+    }
+    void Write(const Entry& entry) override;
+};
+
+/**
+ * Backend that writes to stderr and with color
+ */
+class ColorConsoleBackend : public Backend {
+public:
+    static const char* Name() {
+        return "color_console";
+    }
+
+    const char* GetName() const override {
+        return Name();
+    }
+    void Write(const Entry& entry) override;
+};
+
+/**
+ * Backend that writes to a file passed into the constructor
+ */
+class FileBackend : public Backend {
+public:
+    explicit FileBackend(const std::string& filename);
+
+    static const char* Name() {
+        return "file";
+    }
+
+    const char* GetName() const override {
+        return Name();
+    }
+
+    void Write(const Entry& entry) override;
+
+private:
+    FileUtil::IOFile file;
+    size_t bytes_written;
+};
+
+void AddBackend(std::unique_ptr<Backend> backend);
+
+void RemoveBackend(const std::string& backend_name);
+
+Backend* GetBackend(const std::string& backend_name);
+
+/**
  * Returns the name of the passed log class as a C-string. Subclasses are separated by periods
  * instead of underscores as in the enumeration.
  */
@@ -49,5 +125,10 @@ const char* GetLevelName(Level log_level);
 Entry CreateEntry(Class log_class, Level log_level, const char* filename, unsigned int line_nr,
                   const char* function, std::string message);
 
-void SetFilter(Filter* filter);
-} // namespace Log
+/**
+ * The global filter will prevent any messages from even being processed if they are filtered. Each
+ * backend can have a filter, but if the level is lower than the global filter, the backend will
+ * never get the message
+ */
+void SetGlobalFilter(const Filter& filter);
+} // namespace Log
\ No newline at end of file
diff --git a/src/common/logging/filter.cpp b/src/common/logging/filter.cpp
index 428723dce..4e783a577 100644
--- a/src/common/logging/filter.cpp
+++ b/src/common/logging/filter.cpp
@@ -65,14 +65,14 @@ bool Filter::ParseFilterRule(const std::string::const_iterator begin,
                              const std::string::const_iterator end) {
     auto level_separator = std::find(begin, end, ':');
     if (level_separator == end) {
-        NGLOG_ERROR(Log, "Invalid log filter. Must specify a log level after `:`: %s",
-                    std::string(begin, end).c_str());
+        LOG_ERROR(Log, "Invalid log filter. Must specify a log level after `:`: {}",
+                  std::string(begin, end));
         return false;
     }
 
     const Level level = GetLevelByName(level_separator + 1, end);
     if (level == Level::Count) {
-        NGLOG_ERROR(Log, "Unknown log level in filter: %s", std::string(begin, end).c_str());
+        LOG_ERROR(Log, "Unknown log level in filter: {}", std::string(begin, end));
         return false;
     }
 
@@ -83,7 +83,7 @@ bool Filter::ParseFilterRule(const std::string::const_iterator begin,
 
     const Class log_class = GetClassByName(begin, level_separator);
     if (log_class == Class::Count) {
-        NGLOG_ERROR(Log, "Unknown log class in filter: %s", std::string(begin, end).c_str());
+        LOG_ERROR(Log, "Unknown log class in filter: {}", std::string(begin, end));
         return false;
     }
 
diff --git a/src/common/logging/log.h b/src/common/logging/log.h
index c5015531c..e96c90e16 100644
--- a/src/common/logging/log.h
+++ b/src/common/logging/log.h
@@ -109,25 +109,25 @@ void FmtLogMessage(Class log_class, Level log_level, const char* filename, unsig
 } // namespace Log
 
 #ifdef _DEBUG
-#define NGLOG_TRACE(log_class, ...)                                                                \
+#define LOG_TRACE(log_class, ...)                                                                  \
     ::Log::FmtLogMessage(::Log::Class::log_class, ::Log::Level::Trace, __FILE__, __LINE__,         \
                          __func__, __VA_ARGS__)
 #else
-#define NGLOG_TRACE(log_class, fmt, ...) (void(0))
+#define LOG_TRACE(log_class, fmt, ...) (void(0))
 #endif
 
-#define NGLOG_DEBUG(log_class, ...)                                                                \
+#define LOG_DEBUG(log_class, ...)                                                                  \
     ::Log::FmtLogMessage(::Log::Class::log_class, ::Log::Level::Debug, __FILE__, __LINE__,         \
                          __func__, __VA_ARGS__)
-#define NGLOG_INFO(log_class, ...)                                                                 \
+#define LOG_INFO(log_class, ...)                                                                   \
     ::Log::FmtLogMessage(::Log::Class::log_class, ::Log::Level::Info, __FILE__, __LINE__,          \
                          __func__, __VA_ARGS__)
-#define NGLOG_WARNING(log_class, ...)                                                              \
+#define LOG_WARNING(log_class, ...)                                                                \
     ::Log::FmtLogMessage(::Log::Class::log_class, ::Log::Level::Warning, __FILE__, __LINE__,       \
                          __func__, __VA_ARGS__)
-#define NGLOG_ERROR(log_class, ...)                                                                \
+#define LOG_ERROR(log_class, ...)                                                                  \
     ::Log::FmtLogMessage(::Log::Class::log_class, ::Log::Level::Error, __FILE__, __LINE__,         \
                          __func__, __VA_ARGS__)
-#define NGLOG_CRITICAL(log_class, ...)                                                             \
+#define LOG_CRITICAL(log_class, ...)                                                               \
     ::Log::FmtLogMessage(::Log::Class::log_class, ::Log::Level::Critical, __FILE__, __LINE__,      \
                          __func__, __VA_ARGS__)
diff --git a/src/common/memory_util.cpp b/src/common/memory_util.cpp
index 4d1ec8fb9..5d89209ed 100644
--- a/src/common/memory_util.cpp
+++ b/src/common/memory_util.cpp
@@ -55,7 +55,7 @@ void* AllocateExecutableMemory(size_t size, bool low) {
     if (ptr == MAP_FAILED) {
         ptr = nullptr;
 #endif
-        NGLOG_ERROR(Common_Memory, "Failed to allocate executable memory");
+        LOG_ERROR(Common_Memory, "Failed to allocate executable memory");
     }
 #if !defined(_WIN32) && defined(ARCHITECTURE_X64) && !defined(MAP_32BIT)
     else {
@@ -68,7 +68,7 @@ void* AllocateExecutableMemory(size_t size, bool low) {
 
 #if EMU_ARCH_BITS == 64
     if ((u64)ptr >= 0x80000000 && low == true)
-        NGLOG_ERROR(Common_Memory, "Executable memory ended up above 2GB!");
+        LOG_ERROR(Common_Memory, "Executable memory ended up above 2GB!");
 #endif
 
     return ptr;
@@ -85,7 +85,7 @@ void* AllocateMemoryPages(size_t size) {
 #endif
 
     if (ptr == nullptr)
-        NGLOG_ERROR(Common_Memory, "Failed to allocate raw memory");
+        LOG_ERROR(Common_Memory, "Failed to allocate raw memory");
 
     return ptr;
 }
@@ -99,12 +99,12 @@ void* AllocateAlignedMemory(size_t size, size_t alignment) {
     ptr = memalign(alignment, size);
 #else
     if (posix_memalign(&ptr, alignment, size) != 0)
-        NGLOG_ERROR(Common_Memory, "Failed to allocate aligned memory");
+        LOG_ERROR(Common_Memory, "Failed to allocate aligned memory");
 #endif
 #endif
 
     if (ptr == nullptr)
-        NGLOG_ERROR(Common_Memory, "Failed to allocate aligned memory");
+        LOG_ERROR(Common_Memory, "Failed to allocate aligned memory");
 
     return ptr;
 }
@@ -113,7 +113,7 @@ void FreeMemoryPages(void* ptr, size_t size) {
     if (ptr) {
 #ifdef _WIN32
         if (!VirtualFree(ptr, 0, MEM_RELEASE))
-            NGLOG_ERROR(Common_Memory, "FreeMemoryPages failed!\n{}", GetLastErrorMsg());
+            LOG_ERROR(Common_Memory, "FreeMemoryPages failed!\n{}", GetLastErrorMsg());
 #else
         munmap(ptr, size);
 #endif
@@ -134,7 +134,7 @@ void WriteProtectMemory(void* ptr, size_t size, bool allowExecute) {
 #ifdef _WIN32
     DWORD oldValue;
     if (!VirtualProtect(ptr, size, allowExecute ? PAGE_EXECUTE_READ : PAGE_READONLY, &oldValue))
-        NGLOG_ERROR(Common_Memory, "WriteProtectMemory failed!\n{}", GetLastErrorMsg());
+        LOG_ERROR(Common_Memory, "WriteProtectMemory failed!\n{}", GetLastErrorMsg());
 #else
     mprotect(ptr, size, allowExecute ? (PROT_READ | PROT_EXEC) : PROT_READ);
 #endif
@@ -145,7 +145,7 @@ void UnWriteProtectMemory(void* ptr, size_t size, bool allowExecute) {
     DWORD oldValue;
     if (!VirtualProtect(ptr, size, allowExecute ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE,
                         &oldValue))
-        NGLOG_ERROR(Common_Memory, "UnWriteProtectMemory failed!\n{}", GetLastErrorMsg());
+        LOG_ERROR(Common_Memory, "UnWriteProtectMemory failed!\n{}", GetLastErrorMsg());
 #else
     mprotect(ptr, size,
              allowExecute ? (PROT_READ | PROT_WRITE | PROT_EXEC) : PROT_WRITE | PROT_READ);
diff --git a/src/common/param_package.cpp b/src/common/param_package.cpp
index ab0154133..e0df430ab 100644
--- a/src/common/param_package.cpp
+++ b/src/common/param_package.cpp
@@ -25,7 +25,7 @@ ParamPackage::ParamPackage(const std::string& serialized) {
         std::vector<std::string> key_value;
         Common::SplitString(pair, KEY_VALUE_SEPARATOR, key_value);
         if (key_value.size() != 2) {
-            NGLOG_ERROR(Common, "invalid key pair {}", pair);
+            LOG_ERROR(Common, "invalid key pair {}", pair);
             continue;
         }
 
@@ -64,7 +64,7 @@ std::string ParamPackage::Serialize() const {
 std::string ParamPackage::Get(const std::string& key, const std::string& default_value) const {
     auto pair = data.find(key);
     if (pair == data.end()) {
-        NGLOG_DEBUG(Common, "key '{}' not found", key);
+        LOG_DEBUG(Common, "key '{}' not found", key);
         return default_value;
     }
 
@@ -74,14 +74,14 @@ std::string ParamPackage::Get(const std::string& key, const std::string& default
 int ParamPackage::Get(const std::string& key, int default_value) const {
     auto pair = data.find(key);
     if (pair == data.end()) {
-        NGLOG_DEBUG(Common, "key '{}' not found", key);
+        LOG_DEBUG(Common, "key '{}' not found", key);
         return default_value;
     }
 
     try {
         return std::stoi(pair->second);
     } catch (const std::logic_error&) {
-        NGLOG_ERROR(Common, "failed to convert {} to int", pair->second);
+        LOG_ERROR(Common, "failed to convert {} to int", pair->second);
         return default_value;
     }
 }
@@ -89,14 +89,14 @@ int ParamPackage::Get(const std::string& key, int default_value) const {
 float ParamPackage::Get(const std::string& key, float default_value) const {
     auto pair = data.find(key);
     if (pair == data.end()) {
-        NGLOG_DEBUG(Common, "key {} not found", key);
+        LOG_DEBUG(Common, "key {} not found", key);
         return default_value;
     }
 
     try {
         return std::stof(pair->second);
     } catch (const std::logic_error&) {
-        NGLOG_ERROR(Common, "failed to convert {} to float", pair->second);
+        LOG_ERROR(Common, "failed to convert {} to float", pair->second);
         return default_value;
     }
 }
diff --git a/src/common/string_util.cpp b/src/common/string_util.cpp
index 646400db0..ea9d8f77c 100644
--- a/src/common/string_util.cpp
+++ b/src/common/string_util.cpp
@@ -281,7 +281,7 @@ static std::string CodeToUTF8(const char* fromcode, const std::basic_string<T>&
 
     iconv_t const conv_desc = iconv_open("UTF-8", fromcode);
     if ((iconv_t)(-1) == conv_desc) {
-        NGLOG_ERROR(Common, "Iconv initialization failure [{}]: {}", fromcode, strerror(errno));
+        LOG_ERROR(Common, "Iconv initialization failure [{}]: {}", fromcode, strerror(errno));
         iconv_close(conv_desc);
         return {};
     }
@@ -310,7 +310,7 @@ static std::string CodeToUTF8(const char* fromcode, const std::basic_string<T>&
                     ++src_buffer;
                 }
             } else {
-                NGLOG_ERROR(Common, "iconv failure [{}]: {}", fromcode, strerror(errno));
+                LOG_ERROR(Common, "iconv failure [{}]: {}", fromcode, strerror(errno));
                 break;
             }
         }
@@ -329,7 +329,7 @@ std::u16string UTF8ToUTF16(const std::string& input) {
 
     iconv_t const conv_desc = iconv_open("UTF-16LE", "UTF-8");
     if ((iconv_t)(-1) == conv_desc) {
-        NGLOG_ERROR(Common, "Iconv initialization failure [UTF-8]: {}", strerror(errno));
+        LOG_ERROR(Common, "Iconv initialization failure [UTF-8]: {}", strerror(errno));
         iconv_close(conv_desc);
         return {};
     }
@@ -358,7 +358,7 @@ std::u16string UTF8ToUTF16(const std::string& input) {
                     ++src_buffer;
                 }
             } else {
-                NGLOG_ERROR(Common, "iconv failure [UTF-8]: {}", strerror(errno));
+                LOG_ERROR(Common, "iconv failure [UTF-8]: {}", strerror(errno));
                 break;
             }
         }