1 files changed, 69 insertions, 0 deletions
diff --git a/src/base/message_handler.cc b/src/base/message_handler.cc
new file mode 100644
index 0000000..70959c0
--- /dev/null
+++ b/src/base/message_handler.cc
@@ -0,0 +1,69 @@
+#include "image_io/base/message_handler.h"
+
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "image_io/base/cout_message_writer.h"
+
+namespace photos_editing_formats {
+namespace image_io {
+
+using std::string;
+using std::unique_ptr;
+
+/// The message handler. No effort made to delete it at program's end.
+static MessageHandler* gMessageHandler = nullptr;
+
+void MessageHandler::Init(std::unique_ptr<MessageWriter> message_writer,
+                          std::unique_ptr<MessageStore> message_store) {
+  auto* old_handler = gMessageHandler;
+  gMessageHandler = new MessageHandler;
+  gMessageHandler->SetMessageWriter(std::move(message_writer));
+  gMessageHandler->SetMessageStore(std::move(message_store));
+  delete old_handler;
+}
+
+MessageHandler* MessageHandler::Get() {
+  if (!gMessageHandler) {
+    gMessageHandler = new MessageHandler;
+    gMessageHandler->SetMessageWriter(
+        unique_ptr<MessageWriter>(new CoutMessageWriter));
+    gMessageHandler->SetMessageStore(
+        unique_ptr<MessageStore>(new VectorMessageStore));
+  }
+  return gMessageHandler;
+}
+
+MessageHandler::~MessageHandler() {
+  if (gMessageHandler == this) {
+    gMessageHandler = nullptr;
+  }
+}
+
+void MessageHandler::SetMessageWriter(
+    std::unique_ptr<MessageWriter> message_writer) {
+  message_writer_ = std::move(message_writer);
+}
+
+void MessageHandler::SetMessageStore(
+    std::unique_ptr<MessageStore> message_store) {
+  message_store_ = std::move(message_store);
+}
+
+void MessageHandler::ReportMessage(Message::Type type, const string& text) {
+  int system_errno = (type == Message::kStdLibError) ? errno : 0;
+  ReportMessage(Message(type, system_errno, text));
+}
+
+void MessageHandler::ReportMessage(const Message& message) {
+  if (message_store_) {
+    message_store_->AddMessage(message);
+  }
+  if (message_writer_) {
+    message_writer_->WriteMessage(message);
+  }
+}
+
+}  // namespace image_io
+}  // namespace photos_editing_formats