1 files changed, 56 insertions, 0 deletions
diff --git a/src/carbon.c b/src/carbon.c
new file mode 100644
index 0000000..98e2793
--- /dev/null
+++ b/src/carbon.c
@@ -0,0 +1,56 @@
+#include <Carbon/Carbon.h>
+
+struct carbon_event
+{
+    EventTargetRef target;
+    EventHandlerUPP handler;
+    EventTypeSpec type;
+    EventHandlerRef handler_ref;
+    char * volatile process_name;
+};
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated"
+static OSStatus
+carbon_event_handler(EventHandlerCallRef ref, EventRef event, void *context)
+{
+    struct carbon_event *carbon = (struct carbon_event *) context;
+
+    ProcessSerialNumber psn;
+    if (GetEventParameter(event,
+                          kEventParamProcessID,
+                          typeProcessSerialNumber,
+                          NULL,
+                          sizeof(psn),
+                          NULL,
+                          &psn) != noErr) {
+        return -1;
+    }
+
+    CFStringRef process_name_ref;
+    if (CopyProcessName(&psn, &process_name_ref) == noErr) {
+        if (carbon->process_name) free(carbon->process_name);
+        carbon->process_name = copy_cfstring(process_name_ref);
+        printf("front app changed: %s\n", carbon->process_name);
+        CFRelease(process_name_ref);
+    }
+
+    return noErr;
+}
+#pragma clang diagnostic pop
+
+bool carbon_event_init(struct carbon_event *carbon)
+{
+    carbon->target = GetApplicationEventTarget();
+    carbon->handler = NewEventHandlerUPP(carbon_event_handler);
+    carbon->type.eventClass = kEventClassApplication;
+    carbon->type.eventKind = kEventAppFrontSwitched;
+    carbon->process_name = NULL;
+
+    return InstallEventHandler(carbon->target,
+                               carbon->handler,
+                               1,
+                               &carbon->type,
+                               carbon,
+                               &carbon->handler_ref) == noErr;
+}