mediapipe/third_party/opencv_ios_source.bzl

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# Copyright 2023 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.
"""Custom rules for building iOS OpenCV xcframework from sources."""
load(
"@//third_party:opencv_ios_xcframework_files.bzl",
"OPENCV_XCFRAMEWORK_IOS_SIMULATOR_FILE_PATHS",
"OPENCV_XCFRAMEWORK_IOS_DEVICE_FILE_PATHS",
"OPENCV_XCFRAMEWORK_INFO_PLIST_PATH"
)
_OPENCV_XCFRAMEWORK_DIR_NAME = "opencv2.xcframework"
_OPENCV_FRAMEWORK_DIR_NAME = "opencv2.framework"
_OPENCV_SIMULATOR_PLATFORM_DIR_NAME = "ios-arm64_x86_64-simulator"
_OPENCV_DEVICE_PLATFORM_DIR_NAME = "ios-arm64"
_OPENCV_PLATFORM_DIR_NAMES = [_OPENCV_SIMULATOR_PLATFORM_DIR_NAME, _OPENCV_DEVICE_PLATFORM_DIR_NAME]
def _select_headers_impl(ctx):
_files = [f for f in ctx.files.srcs
if (f.basename.endswith(".h") or f.basename.endswith(".hpp"))
and f.dirname.find(ctx.attr.platform) != -1]
return [DefaultInfo(files = depset(_files))]
# This rule selects only the headers from an apple static xcframework filtered by
# an input platform string.
select_headers = rule(
implementation = _select_headers_impl,
attrs = {
"srcs": attr.label_list(mandatory = True, allow_files=True),
"platform": attr.string(mandatory = True),
},
)
# This function declares and returns symlinks to the directories within each platform
# in `opencv2.xcframework` expected to be present.
# The symlinks are created according to the structure stipulated by apple xcframeworks
# do that they can be correctly consumed by `apple_static_xcframework_import` rule.
def _opencv2_directory_symlinks(ctx, platforms):
basenames = ['Resources', 'Headers', 'Modules', 'Versions/Current']
symlinks = []
for platform in platforms:
symlinks = symlinks + [
ctx.actions.declare_symlink(
_OPENCV_XCFRAMEWORK_DIR_NAME + "/{}/{}/{}".format(platform, _OPENCV_FRAMEWORK_DIR_NAME, name)
) for name in basenames]
return symlinks
# This function declares and returns all the files for each platform expected
# to be present in `opencv2.xcframework` after the unzipping action is run.
def _opencv2_file_list(ctx, platform_filepath_lists):
binary_name = "opencv2"
output_files = []
binaries_to_symlink = []
for (platform, filepaths) in platform_filepath_lists:
for path in filepaths:
file = ctx.actions.declare_file(path)
output_files.append(file)
if path.endswith(binary_name):
symlink_output = ctx.actions.declare_file(
_OPENCV_XCFRAMEWORK_DIR_NAME + "/{}/{}/{}".format(
platform, _OPENCV_FRAMEWORK_DIR_NAME ,binary_name))
binaries_to_symlink.append((symlink_output, file))
return output_files, binaries_to_symlink
def _unzip_opencv_xcframework_impl(ctx):
# Array to iterate over the various platforms to declare output files and
# symlinks.
platform_filepath_lists = [
(_OPENCV_SIMULATOR_PLATFORM_DIR_NAME, OPENCV_XCFRAMEWORK_IOS_SIMULATOR_FILE_PATHS),
(_OPENCV_DEVICE_PLATFORM_DIR_NAME, OPENCV_XCFRAMEWORK_IOS_DEVICE_FILE_PATHS)
]
# Gets an exhaustive list of output files which are present in the xcframework.
# Also gets array of `(binary simlink, binary)` pairs which are to be symlinked
# using `ctx.actions.symlink()`.
output_files, binaries_to_symlink = _opencv2_file_list(ctx, platform_filepath_lists)
output_files.append(ctx.actions.declare_file(OPENCV_XCFRAMEWORK_INFO_PLIST_PATH))
# xcframeworks have a directory structure in which the `opencv2.framework` folders for each
# platform contain directories which are symlinked to the respective folders of the version
# in use. Simply unzipping the zip of the framework will not make Bazel treat these
# as symlinks. They have to be explicity declared as symlinks using `ctx.actions.declare_symlink()`.
directory_symlinks = _opencv2_directory_symlinks(
ctx, [_OPENCV_SIMULATOR_PLATFORM_DIR_NAME, _OPENCV_DEVICE_PLATFORM_DIR_NAME])
output_files = output_files + directory_symlinks
args = ctx.actions.args()
# Add the path of the zip file to be unzipped as an argument to be passed to
# `run_shell` action.
args.add(ctx.file.zip_file.path)
# Add the path to the directory in which the framework is to be unzipped to.
args.add(ctx.file.zip_file.dirname)
ctx.actions.run_shell(
inputs = [ctx.file.zip_file],
outputs = output_files,
arguments = [args],
progress_message = "Unzipping %s" % ctx.file.zip_file.short_path,
command = "unzip -qq $1 -d $2",
)
# The symlinks of the opencv2 binaries for each platform in the xcframework
# have to be symlinked using the `ctx.actions.symlink` unlike the directory
# symlinks which can be expected to be valid when unzipping is completed.
# Otherwise, when tests are run, the linker complaints that the binary is
# not found.
binary_symlink_files = []
for (symlink_output, binary_file) in binaries_to_symlink:
ctx.actions.symlink(output = symlink_output, target_file = binary_file)
binary_symlink_files.append(symlink_output)
# Return all the declared output files and symlinks as the output of this
# rule.
return [ DefaultInfo(files=depset(output_files + binary_symlink_files)) ]
# This rule unzips an `opencv2.xcframework.zip` created by a genrule that
# invokes a python script in the opencv 4.5.1 github archive.
# It returns all the contents of opencv2.xcframework as a list of files in the
# output. This rule works by explicitly declaring files at hardcoded
# paths in the opencv2 xcframework bundle which are expected to be present when
# the zip file is unzipped. This is a prerequisite since the outputs of this rule
# will be consumed by apple_static_xcframework_import which can only take a list
# of files as inputs.
unzip_opencv_xcframework = rule(
implementation = _unzip_opencv_xcframework_impl,
attrs = {
"zip_file": attr.label(mandatory = True, allow_single_file=True),
},
)