Added common utils and string helpers

mediapipe/tasks/ios/common/utils/BUILD

@@ -0,0 +1,41 @@
+# Copyright 2022 The MediaPipe Authors. All Rights Reserved.
+#
+# 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.
+
+package(default_visibility = ["//mediapipe/tasks:internal"])
+
+licenses(["notice"])
+
+objc_library(
+    name = "MPPCommonUtils",
+    srcs = ["sources/MPPCommonUtils.mm"],
+    hdrs = ["sources/MPPCommonUtils.h"],
+    deps = [
+        "//mediapipe/tasks/cc:common",
+        "//mediapipe/tasks/ios/common:MPPCommon",
+        "@com_google_absl//absl/status",
+        "@com_google_absl//absl/strings",
+        "@com_google_absl//absl/strings:cord",
+    ],
+)
+
+objc_library(
+    name = "NSStringHelpers",
+    srcs = ["sources/NSString+Helpers.mm"],
+    hdrs = ["sources/NSString+Helpers.h"],
+    copts = [
+        "-ObjC++",
+        "-std=c++17",
+    ],
+)
+

mediapipe/tasks/ios/common/utils/sources/MPPCommonUtils.h

@@ -0,0 +1,78 @@
+// Copyright 2022 The MediaPipe Authors. All Rights Reserved.
+//
+// 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>
+#include "mediapipe/tasks/cc/common.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** Error domain of Mediapipe Task related errors. */
+extern NSString *const MPPTasksErrorDomain;
+
+/** Helper utility for the all tasks which encapsulates common functionality. */
+@interface MPPCommonUtils : NSObject
+
+/**
+ * Creates and saves an NSError in the Mediapipe task library domain, with the given code and
+ * description.
+ *
+ * @param code Error code.
+ * @param description Error description.
+ * @param error Pointer to the memory location where the created error should be saved. If `nil`,
+ * no error will be saved.
+ */
++ (void)createCustomError:(NSError **)error
+                 withCode:(NSUInteger)code
+              description:(NSString *)description;
+
+/**
+ * Creates and saves an NSError with the given domain, code and description.
+ *
+ * @param error Pointer to the memory location where the created error should be saved. If `nil`,
+ * no error will be saved.
+ * @param domain Error domain.
+ * @param code Error code.
+ * @param description Error description.
+ */
++ (void)createCustomError:(NSError **)error
+               withDomain:(NSString *)domain
+                     code:(NSUInteger)code
+              description:(NSString *)description;
+
+/**
+ * Converts an absl status to an NSError.
+ *
+ * @param status absl status.
+ * @param error Pointer to the memory location where the created error should be saved. If `nil`,
+ * no error will be saved.
+ */
++ (BOOL)checkCppError:(const absl::Status &)status toError:(NSError **)error;
+
+/**
+ * Allocates a block of memory with the specified size and returns a pointer to it. If memory
+ * cannot be allocated because of an invalid memSize, it saves an error. In other cases, it
+ * terminates program execution.
+ *
+ * @param memSize size of memory to be allocated
+ * @param error Pointer to the memory location where errors if any should be saved. If `nil`, no
+ * error will be saved.
+ *
+ * @return Pointer to the allocated block of memory on successfull allocation. nil in case as
+ * error is encountered because of invalid memSize. If failure is due to any other reason, method
+ * terminates program execution.
+ */
++ (void *)mallocWithSize:(size_t)memSize error:(NSError **)error;
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/common/utils/sources/MPPCommonUtils.mm

@@ -0,0 +1,137 @@
+// Copyright 2022 The TensorFlow Authors. All Rights Reserved.
+//
+// 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/common/utils/sources/MPPCommonUtils.h"
+
+#import "mediapipe/tasks/ios/common/sources/MPPCommon.h"
+
+#include <string>
+
+#include "absl/status/status.h"  // from @com_google_absl
+#include "absl/strings/cord.h"   // from @com_google_absl
+
+#include "mediapipe/tasks/cc/common.h"
+
+/** Error domain of MediaPipe task library errors. */
+NSString *const MPPTasksErrorDomain = @"org.mediapipe.tasks";
+
+@implementation MPPCommonUtils
+
++ (void)createCustomError:(NSError **)error
+                 withCode:(NSUInteger)code
+              description:(NSString *)description {
+  [MPPCommonUtils createCustomError:error
+                         withDomain:MPPTasksErrorDomain
+                               code:code
+                        description:description];
+}
+
++ (void)createCustomError:(NSError **)error
+               withDomain:(NSString *)domain
+                     code:(NSUInteger)code
+              description:(NSString *)description {
+  if (error) {
+    *error = [NSError errorWithDomain:domain
+                                 code:code
+                             userInfo:@{NSLocalizedDescriptionKey : description}];
+  }
+}
+
++ (void *)mallocWithSize:(size_t)memSize error:(NSError **)error {
+  if (!memSize) {
+    [MPPCommonUtils createCustomError:error
+                             withCode:MPPTasksErrorCodeInvalidArgumentError
+                          description:@"memSize cannot be zero."];
+    return NULL;
+  }
+
+  void *allocedMemory = malloc(memSize);
+  if (!allocedMemory) {
+    exit(-1);
+  }
+
+  return allocedMemory;
+}
+
++ (BOOL)checkCppError:(const absl::Status &)status toError:(NSError *_Nullable *)error {
+  if (status.ok()) {
+    return YES;
+  }
+  // Payload of absl::Status created by the Media Pipe task library stores an appropriate value of
+  // the enum MediaPipeTasksStatus. The integer value corresponding to the MediaPipeTasksStatus enum
+  // stored in the payload is extracted here to later map to the appropriate error code to be
+  // returned. In cases where the enum is not stored in (payload is NULL or the payload string
+  // cannot be converted to an integer), we set the error code value to be 1
+  // (MPPTasksErrorCodeError of MPPTasksErrorCode used in the iOS library to signify
+  // any errors not falling into other categories.) Since payload is of type absl::Cord that can be
+  // type cast into an absl::optional<std::string>, we use the std::stoi function to convert it into
+  // an integer code if possible.
+  NSUInteger genericErrorCode = MPPTasksErrorCodeError;
+  NSUInteger errorCode;
+  try {
+    // Try converting payload to integer if payload is not empty. Otherwise convert a string
+    // signifying generic error code MPPTasksErrorCodeError to integer.
+    errorCode =
+        (NSUInteger)std::stoi(static_cast<absl::optional<std::string>>(
+                                  status.GetPayload(mediapipe::tasks::kMediaPipeTasksPayload))
+                                  .value_or(std::to_string(genericErrorCode)));
+  } catch (std::invalid_argument &e) {
+    // If non empty payload string cannot be converted to an integer. Set error code to 1(kError).
+    errorCode = MPPTasksErrorCodeError;
+  }
+
+  // If errorCode is outside the range of enum values possible or is
+  // MPPTasksErrorCodeError, we try to map the absl::Status::code() to assign
+  // appropriate MPPTasksErrorCode in default cases. Note:
+  // The mapping to absl::Status::code() is done to generate a more specific error code than
+  // MPPTasksErrorCodeError in cases when the payload can't be mapped to
+  // MPPTasksErrorCode. This can happen when absl::Status returned by TFLite library are in turn returned
+  // without modification by Mediapipe cc library methods.
+  if (errorCode > MPPTasksErrorCodeLast || errorCode <= MPPTasksErrorCodeFirst) {
+    switch (status.code()) {
+      case absl::StatusCode::kInternal:
+        errorCode = MPPTasksErrorCodeError;
+        break;
+      case absl::StatusCode::kInvalidArgument:
+        errorCode = MPPTasksErrorCodeInvalidArgumentError;
+        break;
+      case absl::StatusCode::kNotFound:
+        errorCode = MPPTasksErrorCodeError;
+        break;
+      default:
+        errorCode = MPPTasksErrorCodeError;
+        break;
+    }
+  }
+
+  // Creates the NSEror with the appropriate error
+  // MPPTasksErrorCode and message. MPPTasksErrorCode has a one to one
+  // mapping with MediaPipeTasksStatus starting from the value 1(MPPTasksErrorCodeError)
+  // and hence will be correctly initialized if directly cast from the integer code derived from
+  // MediaPipeTasksStatus stored in its payload. MPPTasksErrorCode omits kOk = 0 of
+  // MediaPipeTasksStatusx.
+  //
+  // Stores a string including absl status code and message(if non empty) as the
+  // error message See
+  // https://github.com/abseil/abseil-cpp/blob/master/absl/status/status.h#L514
+  // for explanation. absl::Status::message() can also be used but not always
+  // guaranteed to be non empty.
+  NSString *description = [NSString
+      stringWithCString:status.ToString(absl::StatusToStringMode::kWithNoExtraData).c_str()
+               encoding:NSUTF8StringEncoding];
+  [MPPCommonUtils createCustomError:error withCode:errorCode description:description];
+  return NO;
+}
+
+@end

mediapipe/tasks/ios/common/utils/sources/NSString+Helpers.h

@@ -0,0 +1,28 @@
+// Copyright 2022 The MediaPipe Authors. All Rights Reserved.
+//
+// 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>
+#include <string>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface NSString (Helpers)
+
+@property(readonly) std::string cppString;
+
++ (NSString *)stringWithCppString:(std::string)text;
+
+@end
+
+NS_ASSUME_NONNULL_END

mediapipe/tasks/ios/common/utils/sources/NSString+Helpers.mm

@@ -0,0 +1,27 @@
+// Copyright 2022 The MediaPipe Authors. All Rights Reserved.
+//
+// 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/common/utils/sources/NSString+Helpers.h"
+
+@implementation NSString (Helpers)
+
+- (std::string)cppString {
+  return std::string(self.UTF8String, [self lengthOfBytesUsingEncoding:NSUTF8StringEncoding]);
+}
+
++ (NSString *)stringWithCppString:(std::string)text {
+  return [NSString stringWithCString:text.c_str() encoding:[NSString defaultCStringEncoding]];
+}
+
+@end