Revert "Remove build.rs (tokio-rs#657)"

This reverts commit ac57645.

.github/workflows/continuous-integration-workflow.yaml

@@ -37,10 +37,6 @@ jobs:
             default: true
             profile: minimal
             components: clippy
-      - name: Install Protoc
-        uses: arduino/setup-protoc@v1
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
       - name: install ninja
         uses: seanmiddleditch/gha-setup-ninja@v3
       - name: clippy
@@ -63,10 +59,6 @@ jobs:
       - uses: actions/checkout@v3
         with:
           submodules: recursive
-      - name: Install Protoc
-        uses: arduino/setup-protoc@v1
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
       - name: install ninja
         uses: seanmiddleditch/gha-setup-ninja@v3
       - name: cargo update -Zminimal-versions
@@ -104,10 +96,6 @@ jobs:
             toolchain: ${{ matrix.toolchain }}
             default: true
             profile: minimal
-      - name: Install Protoc
-        uses: arduino/setup-protoc@v1
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
       - name: install ninja
         uses: seanmiddleditch/gha-setup-ninja@v3
       - uses: Swatinem/rust-cache@v1
@@ -135,10 +123,6 @@ jobs:
             toolchain: nightly
             default: true
             profile: minimal
-      - name: Install Protoc
-        uses: arduino/setup-protoc@v1
-        with:
-          repo-token: ${{ secrets.GITHUB_TOKEN }}
       - uses: Swatinem/rust-cache@v1
       - name: install cargo-no-std-check
         uses: actions-rs/cargo@v1
@@ -165,3 +149,21 @@ jobs:
         with:
           command: check
           args: --manifest-path prost-build/Cargo.toml
+
+  vendored:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout
+        uses: actions/checkout@v2
+        with:
+          submodules: recursive
+      - name: install toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+            toolchain: stable
+            default: true
+            profile: minimal
+      - uses: Swatinem/rust-cache@v1
+      - name: cargo check
+        run: cd test-vendored && cargo check
+

.gitignore

@@ -1,4 +1,2 @@
 target
 Cargo.lock
-
-.DS_Store

Cargo.toml

@@ -36,6 +36,7 @@ exclude = [
   "fuzz",
   # Same counts for the afl fuzz targets
   "afl",
+  "test-vendored"
 ]
 
 [lib]

bootstrap/src/lib.rs

@@ -6,19 +6,14 @@ use std::fs;
 use std::io::Read;
 use std::io::Write;
 use std::path::Path;
-use std::path::PathBuf;
 
 /// Test which bootstraps protobuf.rs and compiler.rs from the .proto definitions in the Protobuf
 /// repo. Ensures that the checked-in compiled versions are up-to-date.
 #[test]
 fn bootstrap() {
-    let include = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-        .parent()
-        .unwrap()
-        .join("tests")
-        .join("src")
-        .join("include");
-    let protobuf = include.join("google").join("protobuf");
+    let protobuf = prost_build::protoc_include()
+        .join("google")
+        .join("protobuf");
 
     let tempdir = tempfile::Builder::new()
         .prefix("prost-types-bootstrap")
@@ -45,7 +40,7 @@ fn bootstrap() {
                 protobuf.join("timestamp.proto"),
                 protobuf.join("type.proto"),
             ],
-            &[include],
+            &[""],
         )
         .unwrap();
 

prost-build/Cargo.toml

@@ -16,6 +16,7 @@ rust-version = "1.56"
 
 [features]
 default = []
+vendored = []
 # When MSRV moves to 1.60, these can change to dep:
 cleanup-markdown = ["pulldown-cmark", "pulldown-cmark-to-cmark"]
 
@@ -31,12 +32,15 @@ prost-types = { version = "0.11.0", path = "../prost-types", default-features =
 tempfile = "3"
 lazy_static = "1.4.0"
 regex = { version = "1.5.5", default-features = false, features = ["std", "unicode-bool"] }
-which = "4"
-
-# These two must be kept in sync, used for `cleanup-markdown` feature.
+# These two must be kept in sync
 pulldown-cmark = { version = "0.9.1", optional = true, default-features = false }
 pulldown-cmark-to-cmark = { version = "10.0.1", optional = true }
 
+[build-dependencies]
+which = { version = "4", default-features = false }
+cfg-if = "1"
+cmake = "0.1"
+
 [dev-dependencies]
 env_logger = { version = "0.8", default-features = false }
 

prost-build/build.rs

@@ -0,0 +1,120 @@
+//! Finds the appropriate `protoc` binary and Protobuf include directory for this host, and outputs
+//! build directives so that the main `prost-build` crate can use them.
+//!
+//! This build script attempts to find `protoc` in a few ways:
+//!
+//!     1. If `PROTOC_NO_VENDOR` is enabled, it will check the `PROTOC` environment variable
+//!         then check the `PATH` for a `protoc` or `protoc.exe`.
+//!     2. If the `vendored` feature flag is enabled or `protoc` can't be found via the environment
+//!         variable or in the `PATH` then `prost-build` will attempt to build `protoc` from the
+//!         bundled source code.
+//!     3. Otherwise, it will attempt to execute from the `PATH` and fail if it does not exist.
+//!
+//! The following locations are checked for the Protobuf include directory in decreasing priority:
+//!
+//!     1. The `PROTOC_INCLUDE` environment variable.
+//!     2. The bundled Protobuf include directory.
+//!
+
+use cfg_if::cfg_if;
+use std::env;
+use std::path::PathBuf;
+use which::which;
+
+/// Returns the path to the location of the bundled Protobuf artifacts.
+fn bundle_path() -> PathBuf {
+    env::current_dir().unwrap().join("third-party")
+}
+
+/// Returns the path to the Protobuf include directory pointed to by the `PROTOC_INCLUDE`
+/// environment variable, if it is set.
+fn env_protoc_include() -> Option<PathBuf> {
+    let protoc_include = match env::var_os("PROTOC_INCLUDE") {
+        Some(path) => PathBuf::from(path),
+        None => return None,
+    };
+
+    if !protoc_include.exists() {
+        panic!(
+            "PROTOC_INCLUDE environment variable points to non-existent directory ({:?})",
+            protoc_include
+        );
+    }
+    if !protoc_include.is_dir() {
+        panic!(
+            "PROTOC_INCLUDE environment variable points to a non-directory file ({:?})",
+            protoc_include
+        );
+    }
+
+    Some(protoc_include)
+}
+
+/// Returns the path to the bundled Protobuf include directory.
+fn bundled_protoc_include() -> PathBuf {
+    bundle_path().join("include")
+}
+
+/// Check for `protoc` via the `PROTOC` env var or in the `PATH`.
+fn path_protoc() -> Option<PathBuf> {
+    env::var_os("PROTOC")
+        .map(PathBuf::from)
+        .or_else(|| which("protoc").ok())
+}
+
+/// Returns true if the vendored flag is enabled.
+fn vendored() -> bool {
+    cfg_if! {
+        if #[cfg(feature = "vendored")] {
+            true
+        } else {
+            false
+        }
+    }
+}
+
+/// Compile `protoc` via `cmake`.
+fn compile() -> Option<PathBuf> {
+    let protobuf_src = bundle_path().join("protobuf").join("cmake");
+
+    println!("cargo:rerun-if-changed={}", protobuf_src.display());
+
+    let dst = cmake::Config::new(protobuf_src)
+        .define("protobuf_BUILD_TESTS", "OFF")
+        .build();
+
+    Some(dst.join("bin").join("protoc"))
+}
+
+/// Try to find a `protoc` through a few methods.
+///
+/// Check module docs for more info.
+fn protoc() -> Option<PathBuf> {
+    if env::var_os("PROTOC_NO_VENDOR").is_some() {
+        path_protoc()
+    } else if vendored() {
+        compile()
+    } else {
+        path_protoc().or_else(compile)
+    }
+}
+
+fn main() {
+    let protoc = protoc().expect(
+        "Failed to find or build the protoc binary. The PROTOC environment \
+    is not set, `protoc` is not in PATH or you are missing the requirements to compile protobuf \
+    from source. \n \
+    Check out the `prost-build` README for instructions on the requirements: \
+    https://github.com/tokio-rs/prost#generated-code",
+    );
+
+    let protoc_include = env_protoc_include().unwrap_or_else(bundled_protoc_include);
+
+    println!("cargo:rustc-env=PROTOC={}", protoc.display());
+    println!(
+        "cargo:rustc-env=PROTOC_INCLUDE={}",
+        protoc_include.display()
+    );
+    println!("cargo:rerun-if-env-changed=PROTOC");
+    println!("cargo:rerun-if-env-changed=PROTOC_INCLUDE");
+}