carbon.c

#include "carbon.h"

#define internal static

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated"
internal inline char *
find_process_name_for_psn(ProcessSerialNumber *psn)
{
    CFStringRef process_name_ref;
    if (CopyProcessName(psn, &process_name_ref) == noErr) {
        char *process_name = copy_cfstring(process_name_ref);
        for (char *s = process_name; *s; ++s) *s = tolower(*s);
        CFRelease(process_name_ref);
        return process_name;
    }
    return NULL;
}

inline char *
find_process_name_for_pid(pid_t pid)
{
    ProcessSerialNumber psn;
    GetProcessForPID(pid, &psn);
    return find_process_name_for_psn(&psn);
}

internal inline char *
find_active_process_name(void)
{
    ProcessSerialNumber psn;
    GetFrontProcess(&psn);
    return find_process_name_for_psn(&psn);
}
#pragma clang diagnostic pop

internal 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;
    }

    if (carbon->process_name) {
        free(carbon->process_name);
        carbon->process_name = NULL;
    }

    carbon->process_name = find_process_name_for_psn(&psn);

    return noErr;
}

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 = find_active_process_name();

    return InstallEventHandler(carbon->target,
                               carbon->handler,
                               1,
                               &carbon->type,
                               carbon,
                               &carbon->handler_ref) == noErr;
}