Detect volume button press on jailed iOS device

VolumePressDetect.m

/* MIT License */

#import <Foundation/Foundation.h>
#import <objc/runtime.h>
#import <objc/message.h>
#import <os/log.h>

/* this is a way to detect volume button press on jailed iOS device */
/* if you cannot use private frameworks, you could probably look into MPVolumeView*/
/* but i never tried it myself. you may also look into AVAudioSession's outputVolume*/
/* below is a demonstration of detecting if both volume buttons are pressed AT THE SAME TIME */
/* feel free to simplify it according to your needs */

@interface MPVolumeControllerSystemDataSource : NSObject
@property (nonatomic, assign, readwrite) float volume; //last volume
@end

static void (*orig__systemVolumeDidChange)(MPVolumeControllerSystemDataSource*, SEL, id) = NULL;
static void new__systemVolumeDidChange(MPVolumeControllerSystemDataSource *self, SEL _cmd, id arg1) {
    static NSTimeInterval lastCallTime = 0;
    static float lastVol = -1.0f;
    static const NSTimeInterval pressThreshold = 0.05; /* gap threshold of 1st & 2nd button time press in ms*/
    static const float EPSILON = 0.0005f; /* ts is the tolerance. can be tuned by net change delta of newVol - lastVol */

    NSTimeInterval now = CFAbsoluteTimeGetCurrent();
    float currentVol = self.volume;

    orig__systemVolumeDidChange(self, _cmd, arg1);

    NSDictionary *userInfo = [arg1 userInfo];
    float newVol = [userInfo[@"Volume"] floatValue];

    if (lastCallTime > 0 && (now - lastCallTime) <= pressThreshold && fabs(newVol - lastVol) <= EPSILON) {
        os_log(OS_LOG_DEFAULT, "[volumetweak] both vol press detected."); /* you can call any function here */
    }

    lastCallTime = now;
    lastVol = currentVol;
}

__attribute__((constructor)) static void initialize(void) {
    const Class className = objc_getClass("MPVolumeControllerSystemDataSource");
    const Method method = class_getInstanceMethod(className, sel_registerName("_systemVolumeDidChange:"));
    orig__systemVolumeDidChange = (void (*)(MPVolumeControllerSystemDataSource*, SEL, id))method_getImplementation(method);
    method_setImplementation(method, (IMP)new__systemVolumeDidChange);

    os_log(OS_LOG_DEFAULT, "[volumetweak] started!");
    ((void (*)(id, SEL))objc_msgSend)(objc_getClass("MPVolumeController"), sel_registerName("new")); /* need to initialize MPVolumeController */
}


/* if you wanna use Theos: */

// %hook MPVolumeControllerSystemDataSource

// static NSTimeInterval lastCallTime = 0;
// static float lastVol = -1.0f;
// static const NSTimeInterval pressThreshold = 0.05; /* gap threshold of 1st & 2nd button time press in ms*/
// static const float EPSILON = 0.0005f; /* ts is the tolerance. can be tuned by net change delta of newVol - lastVol */

// -(void)_systemVolumeDidChange:(id)arg1 {
//     NSTimeInterval now = CFAbsoluteTimeGetCurrent();
//     float currentVol = self.volume;

//     %orig;

//     NSDictionary *userInfo = [arg1 userInfo];
//     float newVol = [userInfo[@"Volume"] floatValue];

//     if (lastCallTime > 0 && (now - lastCallTime) <= pressThreshold && fabs(newVol - lastVol) <= EPSILON) {
//         os_log(OS_LOG_DEFAULT, "[volumetweak] both vol press detected.");
//     }

//     lastCallTime = now;
//     lastVol = currentVol;
// }
// %end

// %ctor {
//     os_log(OS_LOG_DEFAULT, "[volumetweak] started!");
//     ((void (*)(id, SEL))objc_msgSend)(objc_getClass("MPVolumeController"), sel_registerName("new")); /* need to initialize MPVolumeController */
// }