1 files changed, 58 insertions, 0 deletions
diff --git a/platform/ios/src/EAGLContext+MGLAddtions.m b/platform/ios/src/EAGLContext+MGLAddtions.m
new file mode 100644
index 0000000000..0012d00c57
--- /dev/null
+++ b/platform/ios/src/EAGLContext+MGLAddtions.m
@@ -0,0 +1,58 @@
+#import "EAGLContext+MGLAddtions.h"
+#import <objc/runtime.h>
+
+
+NSString *const MapboxEAGLContextWillSwitchNotificationKey = @"MapboxEAGLContextWillSwitcheNotificationKey";
+NSString *const MapboxEAGLContextDidFinishSwitchedNotificationKey = @"MapboxEAGLContextDidFinishSwitchedNotificationKey";
+
+
+@implementation EAGLContext (MGLAddtions)
+
++ (void)load{
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        Class class = [self class];
+
+        SEL originalSelector = @selector(setCurrentContext:);
+        SEL swizzledSelector = @selector(mapbox_setCurrentContext:);
+
+        Method originalMethod = class_getClassMethod(class, originalSelector);
+        Method swizzledMethod = class_getClassMethod(class, swizzledSelector);
+        
+        method_exchangeImplementations(originalMethod, swizzledMethod);
+        
+    });
+}
+
+#pragma mark - Method Swizzling
+
+static EAGLContext *mapboxContext = nil;
+static BOOL currentContextShouldBeMapbox;
+
++ (BOOL)mapbox_setCurrentContext:(EAGLContext *)context{
+    if(context && context == mapboxContext && !currentContextShouldBeMapbox){
+        [[NSNotificationCenter defaultCenter]postNotificationName:MapboxEAGLContextWillSwitchNotificationKey object:nil];
+        return NO;
+    }
+    
+    BOOL bRet = [self mapbox_setCurrentContext:context];
+    
+    if(mapboxContext && context && context != mapboxContext && !currentContextShouldBeMapbox){
+        //other context has been current context
+        [[NSNotificationCenter defaultCenter]postNotificationName:MapboxEAGLContextDidFinishSwitchedNotificationKey object:nil];
+        mapboxContext = nil;
+    }
+    return bRet;
+}
+
+
++ (void)becomeMapboxContext:(EAGLContext *)context{
+    mapboxContext = context;
+    currentContextShouldBeMapbox = YES;
+}
+
++ (void)destoryMapboxContext{
+    currentContextShouldBeMapbox = NO;
+}
+
+@end