Added vision task runner

mediapipe/tasks/ios/vision/core/BUILD

@@ -27,3 +27,16 @@ objc_library(
     module_name = "MPPRunningMode",
 )
 
+objc_library(
+    name = "MPPVisionTaskRunner",
+    srcs = ["sources/MPPVisionTaskRunner.mm"],
+    hdrs = ["sources/MPPVisionTaskRunner.h"],
+    copts = [
+        "-ObjC++",
+        "-std=c++17",
+    ],
+    deps = [
+        ":MPPRunningMode",
+        "//mediapipe/tasks/ios/core:MPPTaskRunner",
+    ],
+)

mediapipe/tasks/ios/vision/core/sources/MPPVisionTaskRunner.h

@@ -0,0 +1,54 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import <Foundation/Foundation.h>
+
+#import "mediapipe/tasks/ios/core/sources/MPPTaskRunner.h"
+#import "mediapipe/tasks/ios/vision/core/sources/MPPRunningMode.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * This class is used to create and call appropriate methods on the C++ Task Runner to initialize,
+ * execute and terminate any MediaPipe vision task.
+ */
+@interface MPPVisionTaskRunner : MPPTaskRunner
+
+/**
+ * Initializes a new `MPPVisionTaskRunner` with the MediaPipe calculator config protol running mode and packetsCallback.
+ *
+ * @param graphConfig A MediaPipe calculator config proto.
+ * @param runningMode MediaPipe vision task running mode.
+ * @param packetsCallback An optional C++ callback function that takes a list of output packets as
+ * the input argument. If provided, the callback must in turn call the block provided by the user in
+ * the appropriate task options.
+ * @param error Pointer to the memory location where errors if any should be
+ * saved. If @c NULL, no error will be saved.
+ *
+ * @return An instance of `MPPVisionTaskRunner` initialized to the given MediaPipe calculator config
+ * proto, running mode and packets callback.
+ */
+- (nullable instancetype)initWithCalculatorGraphConfig:(mediapipe::CalculatorGraphConfig)graphConfig
+                              runningMode:(MPPRunningMode)runningMode
+                              packetsCallback:
+                                  (mediapipe::tasks::core::PacketsCallback)packetsCallback
+                                        error:(NSError **)error;
+
+- (instancetype)init NS_UNAVAILABLE;
+
++ (instancetype)new NS_UNAVAILABLE;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/vision/core/sources/MPPVisionTaskRunner.mm

@@ -0,0 +1,72 @@
+// Copyright 2023 The MediaPipe Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#import "mediapipe/tasks/ios/vision/core/sources/MPPVisionTaskRunner.h"
+
+#import "mediapipe/tasks/ios/common/sources/MPPCommon.h"
+#import "mediapipe/tasks/ios/common/utils/sources/MPPCommonUtils.h"
+
+namespace {
+using ::mediapipe::CalculatorGraphConfig;
+}  // namespace
+
+@interface MPPVisionTaskRunner () {
+  MPPRunningMode _runningMode;
+}
+@end
+
+@implementation MPPVisionTaskRunner
+
+- (nullable instancetype)initWithCalculatorGraphConfig:(mediapipe::CalculatorGraphConfig)graphConfig
+                              runningMode:(MPPRunningMode)runningMode
+                              packetsCallback:
+                                  (mediapipe::tasks::core::PacketsCallback)packetsCallback
+                                        error:(NSError **)error {
+
+  switch (runningMode) {
+    case MPPRunningModeImage:
+    case MPPRunningModeVideo: {
+      if (packetsCallback) {
+        [MPPCommonUtils
+        createCustomError:error
+                 withCode:MPPTasksErrorCodeInvalidArgumentError
+              description:
+                  @"The vision task is in image or video mode, a user-defined result callback should not be provided."];
+        return nil;
+      }
+      break;
+    }
+    case MPPRunningModeLiveStream: {
+      if (!packetsCallback) {
+        [MPPCommonUtils
+        createCustomError:error
+                 withCode:MPPTasksErrorCodeInvalidArgumentError
+              description:
+                  @"The vision task is in live stream mode, a user-defined result callback must be provided."];
+        return nil;
+      }
+      break;
+    }
+    default:
+      break
+  }
+  
+  _runningMode = runningMode;
+  self = [super initWithCalculatorGraphConfig:graphConfig
+                              packetsCallback:packetsCallback
+                                        error:error];
+  return self;
+}
+
+@end