Add absl.

ARCHITECTURE.md

@@ -82,6 +82,20 @@ properties of the app.
 The settings.gradle (or settings.gradle.kts) file configures repositories for
 fetching dependencies, and declares each app module.
 
+### CMake
+
+Contains CMake modules used by the samples. See [CMake/README.md] for details.
+
+[CMake/README.md]: CMake/README.md
+
+### third_party
+
+Contains third-party code used by the samples. These should be kept to a minimum
+to avoid the samples being too difficult to reuse. See [third_party/README.md]
+for more information.
+
+[third_party/README.md]: third_party/README.md
+
 ### Metadata directories
 
 #### .github

CMake/README.md

@@ -0,0 +1,6 @@
+# CMake modules
+
+This directory contains CMake modules used by the samples. They can be imported
+in any sample with `include(<NAME>)`, where `<NAME>` is the name of the module
+file without the extension. For example, `include(absl)` will include absl in
+the build and make those libraries available to the sample.

CMake/absl.cmake

@@ -0,0 +1,2 @@
+include_guard()
+add_subdirectory(${CMAKE_CURRENT_LIST_DIR}/../third_party/absl ${CMAKE_CURRENT_BINARY_DIR}/absl)

build-logic/src/main/java/com/android/ndk/samples/buildlogic/AndroidApplicationConventionPlugin.kt

@@ -8,6 +8,7 @@ import org.gradle.kotlin.dsl.configure
 
 class AndroidApplicationConventionPlugin : Plugin<Project> {
     override fun apply(target: Project) {
+        val modulePath = target.rootProject.rootDir.resolve("CMake")
         with(target) {
             with(pluginManager) {
                 apply("com.android.application")
@@ -19,6 +20,12 @@ class AndroidApplicationConventionPlugin : Plugin<Project> {
                 defaultConfig {
                     minSdk = Versions.MIN_SDK
                     targetSdk = Versions.TARGET_SDK
+
+                    externalNativeBuild {
+                        cmake {
+                            arguments.add("-DCMAKE_MODULE_PATH=$modulePath")
+                        }
+                    }
                 }
                 compileOptions {
                     sourceCompatibility = Versions.JAVA

third_party/.clang-format

@@ -0,0 +1,2 @@
+DisableFormat: true
+SortIncludes: never

third_party/README.md

@@ -0,0 +1,13 @@
+# third_party
+
+This directory contains third-party code used by the samples. Currently this
+directory contains only absl, which provides things like `LOG(ERROR)` and
+`CHECK()`.
+
+Note that absl does **not** have a stable ABI at the time of writing. As such,
+if you are a middleware developer who distributes native libraries in binary
+form (whether `.so` or `.a`), you probably cannot use absl. See [Advice for
+middleware vendors] for more details.
+
+[Advice for middleware vendors]:
+  https://developer.android.com/ndk/guides/middleware-vendors

third_party/absl/.clang-format

@@ -0,0 +1,4 @@
+---
+Language:        Cpp
+BasedOnStyle:  Google
+...

third_party/absl/.github/ISSUE_TEMPLATE/00-bug_report.yml

@@ -0,0 +1,53 @@
+name: Bug Report
+description: Let us know that something does not work as expected.
+title: "[Bug]: Please title this bug report"
+body:
+  - type: textarea
+    id: what-happened
+    attributes:
+      label: Describe the issue
+      description: What happened, and what did you expect to happen?
+    validations:
+      required: true
+  - type: textarea
+    id: steps
+    attributes:
+      label: Steps to reproduce the problem
+      description: It is important that we are able to reproduce the problem that you are experiencing. Please provide all code and relevant steps to reproduce the problem, including your `BUILD`/`CMakeLists.txt` file and build commands. Links to a GitHub branch or [godbolt.org](https://godbolt.org/) that demonstrate the problem are also helpful.
+    validations:
+      required: true
+  - type: textarea
+    id: version
+    attributes:
+      label: What version of Abseil are you using?
+      description: Please include the output of `git rev-parse HEAD` or the name of the LTS release that you are using.
+    validations:
+      required: true
+  - type: textarea
+    id: os
+    attributes:
+      label: What operating system and version are you using?
+      description: If you are using a Linux distribution please include the name and version of the distribution as well.
+    validations:
+      required: true
+  - type: textarea
+    id: compiler
+    attributes:
+      label: What compiler and version are you using?
+      description: Please include the output of `gcc -v` or `clang -v`, or the equivalent for your compiler.
+    validations:
+      required: true
+  - type: textarea
+    id: buildsystem
+    attributes:
+      label: What build system are you using?
+      description: Please include the output of `bazel --version` or `cmake --version`, or the equivalent for your build system.
+    validations:
+      required: true
+  - type: textarea
+    id: additional
+    attributes:
+      label: Additional context
+      description: Add any other context about the problem here.
+    validations:
+      required: false

third_party/absl/.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,5 @@
+blank_issues_enabled: false
+contact_links:
+    - name: Question
+      url: https://github.com/abseil/abseil-cpp/discussions
+      about: Have a question? Ask us anything! :-)

third_party/absl/.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+Thank you for your contribution to Abseil!
+
+Before submitting this PR, please be sure to read our [contributing
+guidelines](https://github.com/abseil/abseil-cpp/blob/master/CONTRIBUTING.md).
+
+If you are a Googler, please also note that it is required that you send us a
+Piper CL instead of using the GitHub pull-request process. The code propagation
+process will deliver the change to GitHub.

third_party/absl/.gitignore

@@ -0,0 +1,17 @@
+# Bzlmod lockfile
+MODULE.bazel.lock
+# Ignore all bazel-* symlinks.
+/bazel-*
+# Ignore Bazel verbose explanations
+--verbose_explanations
+# Ignore CMake usual build directory
+build
+# Ignore Vim files
+*.swp
+# Ignore QtCreator Project file
+CMakeLists.txt.user
+# Ignore VS Code files
+.vscode/*
+# Ignore generated python artifacts
+*.pyc
+copts/__pycache__/

third_party/absl/ABSEIL_ISSUE_TEMPLATE.md

@@ -0,0 +1,22 @@
+Please submit a new Abseil Issue using the template below:
+
+## [Short title of proposed API change(s)]
+
+--------------------------------------------------------------------------------
+--------------------------------------------------------------------------------
+
+## Background
+
+[Provide the background information that is required in order to evaluate the
+proposed API changes. No controversial claims should be made here. If there are
+design constraints that need to be considered, they should be presented here
+**along with justification for those constraints**. Linking to other docs is
+good, but please keep the **pertinent information as self contained** as
+possible in this section.]
+
+## Proposed API Change (s)
+
+[Please clearly describe the API change(s) being proposed. If multiple changes,
+please keep them clearly distinguished. When possible, **use example code
+snippets to illustrate before-after API usages**. List pros-n-cons. Highlight
+the main questions that you want to be answered. Given the Abseil project compatibility requirements, describe why the API change is safe.]

third_party/absl/AUTHORS

@@ -0,0 +1,6 @@
+# This is the list of Abseil authors for copyright purposes.
+#
+# This does not necessarily list everyone who has contributed code, since in
+# some cases, their employer may be the copyright holder.  To see the full list
+# of contributors, see the revision history in source control.
+Google Inc.

third_party/absl/BUILD.bazel

@@ -0,0 +1,25 @@
+#
+# Copyright 2020 The Abseil 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
+#
+#      https://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 = ["//visibility:public"])
+
+licenses(["notice"])  # Apache 2.0
+
+# Expose license for external usage through bazel.
+exports_files([
+    "AUTHORS",
+    "LICENSE",
+])