| # Copyright 2023 The Bazel 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. |
| |
| """ |
| Definition of j2objc_library rule. |
| """ |
| |
| load(":common/cc/cc_common.bzl", "cc_common") |
| load(":common/cc/cc_helper.bzl", "cc_helper") |
| load(":common/cc/cc_info.bzl", "CcInfo") |
| load(":common/cc/semantics.bzl", "semantics") |
| load(":common/objc/attrs.bzl", "common_attrs") |
| load(":common/objc/compilation_support.bzl", "compilation_support") |
| load(":common/objc/j2objc_aspect.bzl", "j2objc_aspect") |
| load(":common/objc/providers.bzl", "J2ObjcEntryClassInfo", "J2ObjcMappingFileInfo") |
| load(":common/objc/transitions.bzl", "apple_crosstool_transition") |
| |
| _MIGRATION_TAG = "__J2OBJC_LIBRARY_MIGRATION_DO_NOT_USE_WILL_BREAK__" |
| |
| def _jre_deps_aspect_impl(_, ctx): |
| if "j2objc_jre_lib" not in ctx.rule.attr.tags: |
| fail("in jre_deps attribute of j2objc_library rule: objc_library rule '%s' is misplaced here (Only J2ObjC JRE libraries are allowed)" % |
| str(ctx.label).removeprefix("@")) |
| return [] |
| |
| jre_deps_aspect = aspect( |
| implementation = _jre_deps_aspect_impl, |
| ) |
| |
| def _check_entry_classes(ctx): |
| entry_classes = ctx.attr.entry_classes |
| remove_dead_code = ctx.fragments.j2objc.remove_dead_code() |
| if remove_dead_code and not entry_classes: |
| fail("Entry classes must be specified when flag --compilation_mode=opt is on in order to perform J2ObjC dead code stripping.") |
| |
| def _entry_class_provider(entry_classes, deps): |
| transitive_entry_classes = [dep[J2ObjcEntryClassInfo].entry_classes for dep in deps if J2ObjcEntryClassInfo in dep] |
| return J2ObjcEntryClassInfo(entry_classes = depset(entry_classes, transitive = transitive_entry_classes)) |
| |
| def _mapping_file_provider(deps): |
| infos = [dep[J2ObjcMappingFileInfo] for dep in deps if J2ObjcMappingFileInfo in dep] |
| transitive_header_mapping_files = [info.header_mapping_files for info in infos] |
| transitive_class_mapping_files = [info.class_mapping_files for info in infos] |
| transitive_dependency_mapping_files = [info.dependency_mapping_files for info in infos] |
| transitive_archive_source_mapping_files = [info.archive_source_mapping_files for info in infos] |
| |
| return J2ObjcMappingFileInfo( |
| header_mapping_files = depset([], transitive = transitive_header_mapping_files), |
| class_mapping_files = depset([], transitive = transitive_class_mapping_files), |
| dependency_mapping_files = depset([], transitive = transitive_dependency_mapping_files), |
| archive_source_mapping_files = depset([], transitive = transitive_archive_source_mapping_files), |
| ) |
| |
| def j2objc_library_lockdown(ctx): |
| if not ctx.fragments.j2objc.j2objc_library_migration(): |
| return |
| if _MIGRATION_TAG not in ctx.attr.tags: |
| fail("j2objc_library is locked. Please do not use this rule since it will be deleted in the future.") |
| |
| def _j2objc_library_impl(ctx): |
| j2objc_library_lockdown(ctx) |
| |
| _check_entry_classes(ctx) |
| |
| common_variables = compilation_support.build_common_variables( |
| ctx = ctx, |
| toolchain = None, |
| deps = ctx.attr.deps + ctx.attr.jre_deps, |
| empty_compilation_artifacts = True, |
| direct_cc_compilation_contexts = [dep[CcInfo].compilation_context for dep in ctx.attr.deps if CcInfo in dep], |
| ) |
| |
| return [ |
| _entry_class_provider(ctx.attr.entry_classes, ctx.attr.deps), |
| _mapping_file_provider(ctx.attr.deps), |
| common_variables.objc_provider, |
| CcInfo( |
| compilation_context = common_variables.objc_compilation_context.create_cc_compilation_context(), |
| linking_context = cc_common.merge_linking_contexts(linking_contexts = common_variables.objc_linking_context.cc_linking_contexts), |
| ), |
| ] |
| |
| j2objc_library = rule( |
| _j2objc_library_impl, |
| doc = """ |
| <p> This rule uses <a href="https://github.com/google/j2objc">J2ObjC</a> to translate Java source |
| files to Objective-C, which then can be used used as dependencies of objc_library and objc_binary |
| rules. Detailed information about J2ObjC itself can be found at <a href="http://j2objc.org">the |
| J2ObjC site</a> |
| </p> |
| <p>Custom J2ObjC transpilation flags can be specified using the build flag |
| <code>--j2objc_translation_flags</code> in the command line. |
| </p> |
| <p>Please note that the translated files included in a j2objc_library target will be |
| compiled using the default compilation configuration, the same configuration as for the sources of |
| an objc_library rule with no compilation options specified in attributes. |
| </p> |
| <p>Plus, generated code is de-duplicated at target level, not source level. If you have two |
| different Java targets that include the same Java source files, you may see a duplicate symbol error |
| at link time. The correct way to resolve this issue is to move the shared Java source files into a |
| separate common target that can be depended upon. |
| </p> |
| """, |
| attrs = { |
| "deps": attr.label_list( |
| allow_rules = ["j2objc_library", "java_library", "java_import", "java_proto_library"], |
| aspects = [j2objc_aspect], |
| doc = """ |
| A list of <code>j2objc_library</code>, <code>java_library</code>, |
| <code>java_import</code> and <code>java_proto_library</code> targets that contain |
| Java files to be transpiled to Objective-C. |
| <p>All <code>java_library</code> and <code>java_import</code> targets that can be reached |
| transitively through <code>exports</code>, <code>deps</code> and <code>runtime_deps</code> |
| will be translated and compiled, including files generated by Java annotation processing. |
| There is no support for code>java_import</code> targets with no <code>srcjar</code> |
| specified. |
| </p> |
| <p>The J2ObjC translation works differently depending on the type of source Java source |
| files included in the transitive closure. For each .java source files included in |
| <code>srcs</code> of <code>java_library</code>, a corresponding .h and .m source file |
| will be generated. For each source jar included in <code>srcs</code> of |
| <code>java_library</code> or <code>srcjar</code> of <code>java_import</code>, a |
| corresponding .h and .m source file will be generated with all the code for that jar. |
| </p> |
| <p>Users can import the J2ObjC-generated header files in their code. The import paths for |
| these files are the root-relative path of the original Java artifacts. For example, |
| <code>//some/package/foo.java</code> has an import path of <code>some/package/foo.h</code> |
| and <code>//some/package/bar.srcjar</code> has <code>some/package/bar.h</code |
| </p> |
| <p> |
| If proto_library rules are in the transitive closure of this rule, J2ObjC protos will also |
| be generated, compiled and linked-in at the binary level. For proto |
| <code>//some/proto/foo.proto</code>, users can reference the generated code using import |
| path <code>some/proto/foo.j2objc.pb.h</code>. |
| </p>""", |
| ), |
| "entry_classes": attr.string_list(doc = """ |
| The list of Java classes whose translated ObjC counterparts will be referenced directly |
| by user ObjC code. This attribute is required if flag <code>--j2objc_dead_code_removal |
| </code> is on. The Java classes should be specified in their canonical names as defined by |
| <a href="http://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.7">the Java |
| Language Specification.</a> |
| When flag <code>--j2objc_dead_code_removal</code> is specified, the list of entry classes |
| will be collected transitively and used as entry points to perform dead code analysis. |
| Unused classes will then be removed from the final ObjC app bundle."""), |
| "jre_deps": attr.label_list( |
| allow_rules = ["objc_library"], |
| aspects = [jre_deps_aspect], |
| doc = """ |
| The list of additional JRE emulation libraries required by all Java code translated by this |
| <code>j2objc_library</code> rule. Only core JRE functionality is linked by default.""", |
| ), |
| } | common_attrs.CC_TOOLCHAIN_RULE, |
| cfg = apple_crosstool_transition, |
| fragments = ["apple", "cpp", "j2objc", "objc"] + semantics.additional_fragments(), |
| toolchains = cc_helper.use_cpp_toolchain(), |
| provides = [CcInfo, J2ObjcEntryClassInfo, J2ObjcMappingFileInfo], |
| ) |