Add example building bzip2

Author: illicitonion

WORKSPACE

@@ -99,3 +99,6 @@ rbe_autoconfig(
 
 load("@io_bazel_rules_rust//:workspace.bzl", "bazel_version")
 bazel_version(name = "bazel_version")
+
+load("@examples//hello_sys:workspace.bzl", "remote_deps")
+remote_deps()

examples/WORKSPACE

@@ -69,3 +69,7 @@ rust_wasm_bindgen_repositories()
 load("@io_bazel_rules_rust//:workspace.bzl", "bazel_version")
 
 bazel_version(name = "bazel_version")
+
+load("@examples//hello_sys:workspace.bzl", "remote_deps")
+
+remote_deps()

examples/hello_sys/BUILD

@@ -0,0 +1,20 @@
+package(default_visibility = ["//visibility:public"])
+
+load(
+    "@io_bazel_rules_rust//rust:rust.bzl",
+    "rust_binary",
+)
+
+rust_binary(
+    name = "hello_sys",
+    srcs = ["src/main.rs"],
+    edition = "2018",
+    deps = ["@bzip2"],
+)
+
+sh_test(
+    name = "test",
+    srcs = ["test.sh"],
+    args = ["$(location :hello_sys)"],
+    data = [":hello_sys"],
+)

examples/hello_sys/bzip2-0.3.3.BUILD

@@ -0,0 +1,21 @@
+load(
+    "@io_bazel_rules_rust//rust:rust.bzl",
+    "rust_library",
+)
+
+rust_library(
+    name = "bzip2",
+    srcs = glob(["**/*.rs"]),
+    crate_root = "src/lib.rs",
+    crate_type = "lib",
+    edition = "2015",
+    rustc_flags = [
+        "--cap-lints=allow",
+    ],
+    version = "0.3.3",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@bzip2_sys",
+        "@libc",
+    ],
+)

examples/hello_sys/bzip2-sys-0.1.9+1.0.8.BUILD

@@ -0,0 +1,41 @@
+load(
+    "@io_bazel_rules_rust//rust:rust.bzl",
+    "rust_library",
+)
+load(
+    "@io_bazel_rules_rust//cargo:cargo_build_script.bzl",
+    "cargo_build_script",
+)
+
+cargo_build_script(
+    name = "bzip2_sys_build_script",
+    srcs = glob(["**/*.rs"]),
+    crate_root = "build.rs",
+    data = glob(["**"]),
+    edition = "2015",
+    rustc_flags = [
+        "--cap-lints=allow",
+    ],
+    version = "0.1.9+1.0.8",
+    deps = [
+        "@cc",
+        "@pkg_config",
+    ],
+)
+
+rust_library(
+    name = "bzip2_sys",
+    srcs = glob(["**/*.rs"]),
+    crate_root = "lib.rs",
+    crate_type = "lib",
+    edition = "2015",
+    rustc_flags = [
+        "--cap-lints=allow",
+    ],
+    version = "0.1.9+1.0.8",
+    visibility = ["//visibility:public"],
+    deps = [
+        ":bzip2_sys_build_script",
+        "@libc",
+    ],
+)

examples/hello_sys/cc-1.0.54.BUILD

@@ -0,0 +1,17 @@
+load(
+    "@io_bazel_rules_rust//rust:rust.bzl",
+    "rust_library",
+)
+
+rust_library(
+    name = "cc",
+    srcs = glob(["**/*.rs"]),
+    crate_root = "src/lib.rs",
+    crate_type = "lib",
+    edition = "2018",
+    rustc_flags = [
+        "--cap-lints=allow",
+    ],
+    version = "1.0.54",
+    visibility = ["//visibility:public"],
+)

examples/hello_sys/pkg-config-0.3.17.BUILD

@@ -0,0 +1,17 @@
+load(
+    "@io_bazel_rules_rust//rust:rust.bzl",
+    "rust_library",
+)
+
+rust_library(
+    name = "pkg_config",
+    srcs = glob(["**/*.rs"]),
+    crate_root = "src/lib.rs",
+    crate_type = "lib",
+    edition = "2015",
+    rustc_flags = [
+        "--cap-lints=allow",
+    ],
+    version = "0.3.17",
+    visibility = ["//visibility:public"],
+)

examples/hello_sys/src/main.rs

@@ -0,0 +1,42 @@
+use bzip2::read::BzEncoder;
+use bzip2::Compression;
+use std::io::Read;
+
+fn main() {
+    let stdin = std::io::stdin();
+    let stdin = stdin.lock();
+    let mut raw_counter = CountingStream::new(stdin);
+
+    let compressed_count = {
+        let compressor = BzEncoder::new(&mut raw_counter, Compression::Best);
+        let mut compressed_counter = CountingStream::new(compressor);
+        std::io::copy(&mut compressed_counter, &mut std::io::sink()).unwrap();
+        compressed_counter.count
+    };
+
+    println!(
+        "Compressed {} to {} bytes",
+        raw_counter.count, compressed_count
+    );
+}
+
+struct CountingStream<R: Read> {
+    stream: R,
+    count: usize,
+}
+
+impl<R: Read> CountingStream<R> {
+    fn new(stream: R) -> Self {
+        CountingStream { stream, count: 0 }
+    }
+}
+
+impl<R: Read> Read for CountingStream<R> {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        let result = self.stream.read(buf);
+        if let Ok(read_bytes) = result {
+            self.count += read_bytes;
+        }
+        result
+    }
+}

examples/hello_sys/test.sh

@@ -0,0 +1,5 @@
+#!/bin/bash -eu
+
+out="$(echo -n "Hello world" | "$1")"
+
+[[ "${out}" == "Compressed 11 to 50 bytes" ]] || (echo "Got ${out}" && exit 1)

examples/hello_sys/workspace.bzl

@@ -0,0 +1,38 @@
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+def remote_deps():
+    http_archive(
+        name = "bzip2",
+        url = "https://crates-io.s3-us-west-1.amazonaws.com/crates/bzip2/bzip2-0.3.3.crate",
+        sha256 = "42b7c3cbf0fa9c1b82308d57191728ca0256cb821220f4e2fd410a72ade26e3b",
+        type = "tar.gz",
+        strip_prefix = "bzip2-0.3.3",
+        build_file = "@examples//hello_sys:bzip2-0.3.3.BUILD",
+    )
+
+    http_archive(
+        name = "bzip2_sys",
+        url = "https://crates-io.s3-us-west-1.amazonaws.com/crates/bzip2-sys/bzip2-sys-0.1.9+1.0.8.crate",
+        sha256 = "ad3b39a260062fca31f7b0b12f207e8f2590a67d32ec7d59c20484b07ea7285e",
+        type = "tar.gz",
+        strip_prefix = "bzip2-sys-0.1.9+1.0.8",
+        build_file = "@examples//hello_sys:bzip2-sys-0.1.9+1.0.8.BUILD",
+    )
+
+    http_archive(
+        name = "cc",
+        url = "https://crates-io.s3-us-west-1.amazonaws.com/crates/cc/cc-1.0.54.crate",
+        sha256 = "7bbb73db36c1246e9034e307d0fba23f9a2e251faa47ade70c1bd252220c8311",
+        type = "tar.gz",
+        strip_prefix = "cc-1.0.54",
+        build_file = "@examples//hello_sys:cc-1.0.54.BUILD",
+    )
+
+    http_archive(
+        name = "pkg_config",
+        url = "https://crates-io.s3-us-west-1.amazonaws.com/crates/pkg-config/pkg-config-0.3.17.crate",
+        sha256 = "05da548ad6865900e60eaba7f589cc0783590a92e940c26953ff81ddbab2d677",
+        type = "tar.gz",
+        strip_prefix = "pkg-config-0.3.17",
+        build_file = "@examples//hello_sys:pkg-config-0.3.17.BUILD",
+    )