tools/maven.bzl

# Copyright (C) 2018 The Dagger 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.

"""Macros to simplify generating maven files.
"""

load("@google_bazel_common//tools/maven:pom_file.bzl", default_pom_file = "pom_file")
load(":maven_info.bzl", "MavenInfo", "collect_maven_info")
load("@google_bazel_common//tools/javadoc:javadoc.bzl", "javadoc_library")
load("@google_bazel_common//tools/jarjar:jarjar.bzl", "jarjar_library")

def pom_file(name, targets, artifact_name, artifact_id, packaging = None, **kwargs):
    default_pom_file(
        name = name,
        targets = targets,
        preferred_group_ids = [
            "com.google.dagger",
            "com.google",
        ],
        template_file = "//tools:pom-template.xml",
        substitutions = {
            "{artifact_name}": artifact_name,
            "{artifact_id}": artifact_id,
            "{packaging}": packaging or "jar",
        },
        excluded_artifacts = ["com.google.auto:auto-common"],
        **kwargs
    )

def gen_maven_artifact(
        name,
        artifact_name,
        artifact_coordinates,
        artifact_target,
        artifact_target_libs = None,
        artifact_target_maven_deps = None,
        artifact_target_maven_deps_banned = None,
        testonly = 0,
        pom_name = "pom",
        packaging = None,
        javadoc_srcs = None,
        javadoc_root_packages = None,
        javadoc_exclude_packages = None,
        javadoc_android_api_level = None,
        shaded_deps = None,
        shaded_rules = None,
        manifest = None,
        lint_deps = None):
    _gen_maven_artifact(
        name,
        artifact_name,
        artifact_coordinates,
        artifact_target,
        artifact_target_libs,
        artifact_target_maven_deps,
        artifact_target_maven_deps_banned,
        testonly,
        pom_name,
        packaging,
        javadoc_srcs,
        javadoc_root_packages,
        javadoc_exclude_packages,
        javadoc_android_api_level,
        shaded_deps,
        shaded_rules,
        manifest,
        lint_deps
    )

def _gen_maven_artifact(
        name,
        artifact_name,
        artifact_coordinates,
        artifact_target,
        artifact_target_libs,
        artifact_target_maven_deps,
        artifact_target_maven_deps_banned,
        testonly,
        pom_name,
        packaging,
        javadoc_srcs,
        javadoc_root_packages,
        javadoc_exclude_packages,
        javadoc_android_api_level,
        shaded_deps,
        shaded_rules,
        manifest,
        lint_deps):
    """Generates the files required for a maven artifact.

    This macro generates the following targets:
        * ":pom": The pom file for the given target and deps
        * ":<NAME>": The artifact file for the given target and deps
        * ":<NAME>-src": The sources jar file for the given target and deps
        * ":<NAME>-javadoc": The javadocs jar file for the given target and deps

    This macro also validates a few things. First, it validates that the
    given "target" is a maven artifact (i.e. the "tags" attribute contains
    "maven_coordinates=..."). Second, it calculates the list of transitive
    dependencies of the target that are not owned by another maven artifact,
    and validates that the given "deps" matches exactly.

    Args:
      name: The name associated with the various output targets.
      artifact_target: The target containing the maven_coordinates.
      artifact_name: The name of the maven artifact.
      artifact_coordinates: The coordinates of the maven artifact in the
                            form: "<group_id>:<artifact_id>:<version>"
      artifact_target_libs: The set of transitive libraries of the target.
      artifact_target_maven_deps: The required maven deps of the target.
      artifact_target_maven_deps_banned: The banned maven deps of the target.
      testonly: True if the jar should be testonly.
      packaging: The packaging of the maven artifact. E.g. "aar"
      pom_name: The name of the pom file (or "pom" if absent).
      javadoc_srcs: The srcs for the javadocs.
      javadoc_root_packages: The root packages for the javadocs.
      javadoc_exclude_packages: The packages to exclude from the javadocs.
      javadoc_android_api_level: The android api level for the javadocs.
      shaded_deps: The shaded deps for the jarjar.
      shaded_rules: The shaded rules for the jarjar.
      manifest: The AndroidManifest.xml to bundle in when packaing an 'aar'.
      lint_deps: The lint targets to be bundled in when packaging an 'aar'.
    """

    _validate_maven_deps(
        name = name + "-validation",
        testonly = 1,
        target = artifact_target,
        expected_artifact = artifact_coordinates,
        expected_libs = artifact_target_libs,
        expected_maven_deps = artifact_target_maven_deps,
        banned_maven_deps = artifact_target_maven_deps_banned,
    )

    shaded_deps = shaded_deps or []
    shaded_rules = shaded_rules or []
    artifact_targets = [artifact_target] + (artifact_target_libs or [])
    lint_deps = lint_deps or []

    # META-INF resources files that can be combined by appending lines.
    merge_meta_inf_files = [
        "gradle/incremental.annotation.processors",
    ]

    artifact_id = artifact_coordinates.split(":")[1]
    pom_file(
        name = pom_name,
        testonly = testonly,
        artifact_id = artifact_id,
        artifact_name = artifact_name,
        packaging = packaging,
        targets = artifact_targets,
    )

    if (packaging == "aar"):
        jarjar_library(
            name = name + "-classes",
            testonly = testonly,
            jars = artifact_targets + shaded_deps,
            rules = shaded_rules,
            merge_meta_inf_files = merge_meta_inf_files,
        )
        if lint_deps:
            # jarjar all lint artifacts since an aar only contains a single lint.jar.
            jarjar_library(
                name = name + "-lint",
                jars = lint_deps,
            )
            lint_jar_name = name + "-lint.jar"
        else:
            lint_jar_name = None

        _package_android_library(
            name = name + "-android-lib",
            manifest = manifest,
            classesJar = name + "-classes.jar",
            lintJar = lint_jar_name,
        )

        # Copy intermediate outputs to final one.
        native.genrule(
            name = name,
            srcs = [name + "-android-lib"],
            outs = [name + ".aar"],
            cmd = "cp $< $@",
        )
    else:
        jarjar_library(
            name = name,
            testonly = testonly,
            jars = artifact_targets + shaded_deps,
            rules = shaded_rules,
            merge_meta_inf_files = merge_meta_inf_files,
        )

    jarjar_library(
        name = name + "-src",
        testonly = testonly,
        jars = [_src_jar(dep) for dep in artifact_targets],
        merge_meta_inf_files = merge_meta_inf_files,
    )

    if javadoc_srcs != None:
        javadoc_library(
            name = name + "-javadoc",
            srcs = javadoc_srcs,
            testonly = testonly,
            root_packages = javadoc_root_packages,
            exclude_packages = javadoc_exclude_packages,
            android_api_level = javadoc_android_api_level,
            deps = artifact_targets,
        )
    else:
        # Build an empty javadoc because Sonatype requires javadocs
        # even if the jar is empty.
        # https://central.sonatype.org/pages/requirements.html#supply-javadoc-and-sources
        native.java_binary(
            name = name + "-javadoc",
        )

def _src_jar(target):
    if target.startswith(":"):
        target = Label("//" + native.package_name() + target)
    else:
        target = Label(target)
    return "//%s:lib%s-src.jar" % (target.package, target.name)

def _validate_maven_deps_impl(ctx):
    """Validates the given Maven target and deps

    Validates that the given "target" is a maven artifact (i.e. the "tags"
    attribute contains "maven_coordinates=..."). Second, it calculates the
    list of transitive dependencies of the target that are not owned by
    another maven artifact, and validates that the given "deps" matches
    exactly.
    """
    target = ctx.attr.target
    artifact = target[MavenInfo].artifact
    if not artifact:
        fail("\t[Error]: %s is not a maven artifact" % target.label)

    if artifact != ctx.attr.expected_artifact:
        fail(
            "\t[Error]: %s expected artifact, %s, but was: %s" % (
                target.label,
                ctx.attr.expected_artifact,
                artifact,
            ),
        )

    all_transitive_deps = target[MavenInfo].all_transitive_deps.to_list()
    maven_nearest_artifacts = target[MavenInfo].maven_nearest_artifacts.to_list()
    maven_transitive_deps = target[MavenInfo].maven_transitive_deps.to_list()

    expected_libs = [dep.label for dep in getattr(ctx.attr, "expected_libs", [])]
    actual_libs = [dep for dep in all_transitive_deps if dep not in maven_transitive_deps]
    _validate_list("artifact_target_libs", actual_libs, expected_libs)

    expected_maven_deps = [dep for dep in getattr(ctx.attr, "expected_maven_deps", [])]
    actual_maven_deps = [_strip_artifact_version(artifact) for artifact in maven_nearest_artifacts]
    _validate_list(
        "artifact_target_maven_deps",
        actual_maven_deps,
        expected_maven_deps,
        ctx.attr.banned_maven_deps,
    )

def _validate_list(name, actual_list, expected_list, banned_list = []):
    missing = sorted(['"{}",'.format(x) for x in actual_list if x not in expected_list])
    if missing:
        fail("\t[Error]: Found missing {}: \n\t\t".format(name) + "\n\t\t".join(missing))

    extra = sorted(['"{}",'.format(x) for x in expected_list if x not in actual_list])
    if extra:
        fail("\t[Error]: Found extra {}: \n\t\t".format(name) + "\n\t\t".join(extra))

    banned = sorted(['"{}",'.format(x) for x in actual_list if x in banned_list])
    if banned:
        fail("\t[Error]: Found banned {}: \n\t\t".format(name) + "\n\t\t".join(banned))

def _strip_artifact_version(artifact):
    return artifact.rsplit(":", 1)[0]

_validate_maven_deps = rule(
    implementation = _validate_maven_deps_impl,
    attrs = {
        "target": attr.label(
            doc = "The target to generate a maven artifact for.",
            aspects = [collect_maven_info],
            mandatory = True,
        ),
        "expected_artifact": attr.string(
            doc = "The artifact name of the target.",
            mandatory = True,
        ),
        "expected_libs": attr.label_list(
            doc = "The set of transitive libraries of the target, if any.",
        ),
        "expected_maven_deps": attr.string_list(
            doc = "The required maven dependencies of the target, if any.",
        ),
        "banned_maven_deps": attr.string_list(
            doc = "The required maven dependencies of the target, if any.",
        ),
    },
)

def _package_android_library_impl(ctx):
    """A very, very simple Android Library (aar) packaging rule.

    This rule only support packaging simple android libraries. No resources
    support, assets, extra libs, jni, nor proguard. This rule is needed because
    there is no 'JarJar equivalent' for AARs and some of our artifacts are
    composed of sources spread across multiple android_library targets.

    See: https://developer.android.com/studio/projects/android-library.html#aar-contents
    """
    inputs = [ctx.file.manifest, ctx.file.classesJar]
    if ctx.file.lintJar:
        inputs.append(ctx.file.lintJar)

    ctx.actions.run_shell(
        inputs = inputs,
        outputs = [ctx.outputs.aar],
        command = """
            TMPDIR="$(mktemp -d)"
            cp {manifest} $TMPDIR/AndroidManifest.xml
            cp {classesJar} $TMPDIR/classes.jar
            if [[ -a {lintJar} ]]; then
                cp {lintJar} $TMPDIR/lint.jar
            fi
            touch $TMPDIR/R.txt
            zip -j {outputFile} $TMPDIR/*
            """.format(
            manifest = ctx.file.manifest.path,
            classesJar = ctx.file.classesJar.path,
            lintJar = ctx.file.lintJar.path if ctx.file.lintJar else "none",
            outputFile = ctx.outputs.aar.path,
        ),
    )

_package_android_library = rule(
    implementation = _package_android_library_impl,
    attrs = {
        "manifest": attr.label(
            doc = "The AndroidManifest.xml file.",
            allow_single_file = True,
            mandatory = True,
        ),
        "classesJar": attr.label(
            doc = "The classes.jar file.",
            allow_single_file = True,
            mandatory = True,
        ),
        "lintJar": attr.label(
            doc = "The lint.jar file.",
            allow_single_file = True,
            mandatory = False,
        ),
    },
    outputs = {
        "aar": "%{name}.aar",
    },
)