1 files changed, 319 insertions, 0 deletions
diff --git a/third_party/rust/clang-sys/build/common.rs b/third_party/rust/clang-sys/build/common.rs
new file mode 100644
index 0000000000..c5e57c61b9
--- /dev/null
+++ b/third_party/rust/clang-sys/build/common.rs
@@ -0,0 +1,319 @@
+// SPDX-License-Identifier: Apache-2.0
+
+extern crate glob;
+
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::env;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+use glob::{MatchOptions, Pattern};
+
+//================================================
+// Commands
+//================================================
+
+thread_local! {
+    /// The errors encountered by the build script while executing commands.
+    static COMMAND_ERRORS: RefCell<HashMap<String, Vec<String>>> = RefCell::default();
+}
+
+/// Adds an error encountered by the build script while executing a command.
+fn add_command_error(name: &str, path: &str, arguments: &[&str], message: String) {
+    COMMAND_ERRORS.with(|e| {
+        e.borrow_mut()
+            .entry(name.into())
+            .or_insert_with(Vec::new)
+            .push(format!(
+                "couldn't execute `{} {}` (path={}) ({})",
+                name,
+                arguments.join(" "),
+                path,
+                message,
+            ))
+    });
+}
+
+/// A struct that prints the errors encountered by the build script while
+/// executing commands when dropped (unless explictly discarded).
+///
+/// This is handy because we only want to print these errors when the build
+/// script fails to link to an instance of `libclang`. For example, if
+/// `llvm-config` couldn't be executed but an instance of `libclang` was found
+/// anyway we don't want to pollute the build output with irrelevant errors.
+#[derive(Default)]
+pub struct CommandErrorPrinter {
+    discard: bool,
+}
+
+impl CommandErrorPrinter {
+    pub fn discard(mut self) {
+        self.discard = true;
+    }
+}
+
+impl Drop for CommandErrorPrinter {
+    fn drop(&mut self) {
+        if self.discard {
+            return;
+        }
+
+        let errors = COMMAND_ERRORS.with(|e| e.borrow().clone());
+
+        if let Some(errors) = errors.get("llvm-config") {
+            println!(
+                "cargo:warning=could not execute `llvm-config` one or more \
+                times, if the LLVM_CONFIG_PATH environment variable is set to \
+                a full path to valid `llvm-config` executable it will be used \
+                to try to find an instance of `libclang` on your system: {}",
+                errors
+                    .iter()
+                    .map(|e| format!("\"{}\"", e))
+                    .collect::<Vec<_>>()
+                    .join("\n  "),
+            )
+        }
+
+        if let Some(errors) = errors.get("xcode-select") {
+            println!(
+                "cargo:warning=could not execute `xcode-select` one or more \
+                times, if a valid instance of this executable is on your PATH \
+                it will be used to try to find an instance of `libclang` on \
+                your system: {}",
+                errors
+                    .iter()
+                    .map(|e| format!("\"{}\"", e))
+                    .collect::<Vec<_>>()
+                    .join("\n  "),
+            )
+        }
+    }
+}
+
+/// Executes a command and returns the `stdout` output if the command was
+/// successfully executed (errors are added to `COMMAND_ERRORS`).
+fn run_command(name: &str, path: &str, arguments: &[&str]) -> Option<String> {
+    let output = match Command::new(path).args(arguments).output() {
+        Ok(output) => output,
+        Err(error) => {
+            let message = format!("error: {}", error);
+            add_command_error(name, path, arguments, message);
+            return None;
+        }
+    };
+
+    if output.status.success() {
+        Some(String::from_utf8_lossy(&output.stdout).into_owned())
+    } else {
+        let message = format!("exit code: {}", output.status);
+        add_command_error(name, path, arguments, message);
+        None
+    }
+}
+
+/// Executes the `llvm-config` command and returns the `stdout` output if the
+/// command was successfully executed (errors are added to `COMMAND_ERRORS`).
+pub fn run_llvm_config(arguments: &[&str]) -> Option<String> {
+    let path = env::var("LLVM_CONFIG_PATH").unwrap_or_else(|_| "llvm-config".into());
+    run_command("llvm-config", &path, arguments)
+}
+
+/// Executes the `xcode-select` command and returns the `stdout` output if the
+/// command was successfully executed (errors are added to `COMMAND_ERRORS`).
+pub fn run_xcode_select(arguments: &[&str]) -> Option<String> {
+    run_command("xcode-select", "xcode-select", arguments)
+}
+
+//================================================
+// Search Directories
+//================================================
+
+/// `libclang` directory patterns for Haiku.
+const DIRECTORIES_HAIKU: &[&str] = &[
+    "/boot/system/lib",
+    "/boot/system/develop/lib",
+    "/boot/system/non-packaged/lib",
+    "/boot/system/non-packaged/develop/lib",
+    "/boot/home/config/non-packaged/lib",
+    "/boot/home/config/non-packaged/develop/lib",
+];
+
+/// `libclang` directory patterns for Linux (and FreeBSD).
+const DIRECTORIES_LINUX: &[&str] = &[
+    "/usr/lib*",
+    "/usr/lib*/*",
+    "/usr/lib*/*/*",
+    "/usr/local/lib*",
+    "/usr/local/lib*/*",
+    "/usr/local/lib*/*/*",
+    "/usr/local/llvm*/lib*",
+];
+
+/// `libclang` directory patterns for macOS.
+const DIRECTORIES_MACOS: &[&str] = &[
+    "/usr/local/opt/llvm*/lib",
+    "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib",
+    "/Library/Developer/CommandLineTools/usr/lib",
+    "/usr/local/opt/llvm*/lib/llvm*/lib",
+];
+
+/// `libclang` directory patterns for Windows.
+const DIRECTORIES_WINDOWS: &[&str] = &[
+    "C:\\LLVM\\lib",
+    "C:\\Program Files*\\LLVM\\lib",
+    "C:\\MSYS*\\MinGW*\\lib",
+    // LLVM + Clang can be installed as a component of Visual Studio.
+    // https://github.com/KyleMayes/clang-sys/issues/121
+    "C:\\Program Files*\\Microsoft Visual Studio\\*\\BuildTools\\VC\\Tools\\Llvm\\**\\bin",
+    // LLVM + Clang can be installed using Scoop (https://scoop.sh).
+    // Other Windows package managers install LLVM + Clang to previously listed
+    // system-wide directories.
+    "C:\\Users\\*\\scoop\\apps\\llvm\\current\\bin",
+];
+
+/// `libclang` directory patterns for illumos
+const DIRECTORIES_ILLUMOS: &[&str] = &[
+    "/opt/ooce/clang-*/lib",
+    "/opt/ooce/llvm-*/lib",
+];
+
+//================================================
+// Searching
+//================================================
+
+/// Finds the files in a directory that match one or more filename glob patterns
+/// and returns the paths to and filenames of those files.
+fn search_directory(directory: &Path, filenames: &[String]) -> Vec<(PathBuf, String)> {
+    // Escape the specified directory in case it contains characters that have
+    // special meaning in glob patterns (e.g., `[` or `]`).
+    let directory = Pattern::escape(directory.to_str().unwrap());
+    let directory = Path::new(&directory);
+
+    // Join the escaped directory to the filename glob patterns to obtain
+    // complete glob patterns for the files being searched for.
+    let paths = filenames
+        .iter()
+        .map(|f| directory.join(f).to_str().unwrap().to_owned());
+
+    // Prevent wildcards from matching path separators to ensure that the search
+    // is limited to the specified directory.
+    let mut options = MatchOptions::new();
+    options.require_literal_separator = true;
+
+    paths
+        .map(|p| glob::glob_with(&p, options))
+        .filter_map(Result::ok)
+        .flatten()
+        .filter_map(|p| {
+            let path = p.ok()?;
+            let filename = path.file_name()?.to_str().unwrap();
+
+            // The `libclang_shared` library has been renamed to `libclang-cpp`
+            // in Clang 10. This can cause instances of this library (e.g.,
+            // `libclang-cpp.so.10`) to be matched by patterns looking for
+            // instances of `libclang`.
+            if filename.contains("-cpp.") {
+                return None;
+            }
+
+            Some((directory.to_owned(), filename.into()))
+        })
+        .collect::<Vec<_>>()
+}
+
+/// Finds the files in a directory (and any relevant sibling directories) that
+/// match one or more filename glob patterns and returns the paths to and
+/// filenames of those files.
+fn search_directories(directory: &Path, filenames: &[String]) -> Vec<(PathBuf, String)> {
+    let mut results = search_directory(directory, filenames);
+
+    // On Windows, `libclang.dll` is usually found in the LLVM `bin` directory
+    // while `libclang.lib` is usually found in the LLVM `lib` directory. To
+    // keep things consistent with other platforms, only LLVM `lib` directories
+    // are included in the backup search directory globs so we need to search
+    // the LLVM `bin` directory here.
+    if cfg!(target_os = "windows") && directory.ends_with("lib") {
+        let sibling = directory.parent().unwrap().join("bin");
+        results.extend(search_directory(&sibling, filenames).into_iter());
+    }
+
+    results
+}
+
+/// Finds the `libclang` static or dynamic libraries matching one or more
+/// filename glob patterns and returns the paths to and filenames of those files.
+pub fn search_libclang_directories(filenames: &[String], variable: &str) -> Vec<(PathBuf, String)> {
+    // Search only the path indicated by the relevant environment variable
+    // (e.g., `LIBCLANG_PATH`) if it is set.
+    if let Ok(path) = env::var(variable).map(|d| Path::new(&d).to_path_buf()) {
+        // Check if the path is a matching file.
+        if let Some(parent) = path.parent() {
+            let filename = path.file_name().unwrap().to_str().unwrap();
+            let libraries = search_directories(parent, filenames);
+            if libraries.iter().any(|(_, f)| f == filename) {
+                return vec![(parent.into(), filename.into())];
+            }
+        }
+
+        // Check if the path is directory containing a matching file.
+        return search_directories(&path, filenames);
+    }
+
+    let mut found = vec![];
+
+    // Search the `bin` and `lib` directories in the directory returned by
+    // `llvm-config --prefix`.
+    if let Some(output) = run_llvm_config(&["--prefix"]) {
+        let directory = Path::new(output.lines().next().unwrap()).to_path_buf();
+        found.extend(search_directories(&directory.join("bin"), filenames));
+        found.extend(search_directories(&directory.join("lib"), filenames));
+        found.extend(search_directories(&directory.join("lib64"), filenames));
+    }
+
+    // Search the toolchain directory in the directory returned by
+    // `xcode-select --print-path`.
+    if cfg!(target_os = "macos") {
+        if let Some(output) = run_xcode_select(&["--print-path"]) {
+            let directory = Path::new(output.lines().next().unwrap()).to_path_buf();
+            let directory = directory.join("Toolchains/XcodeDefault.xctoolchain/usr/lib");
+            found.extend(search_directories(&directory, filenames));
+        }
+    }
+
+    // Search the directories in the `LD_LIBRARY_PATH` environment variable.
+    if let Ok(path) = env::var("LD_LIBRARY_PATH") {
+        for directory in env::split_paths(&path) {
+            found.extend(search_directories(&directory, filenames));
+        }
+    }
+
+    // Determine the `libclang` directory patterns.
+    let directories = if cfg!(target_os = "haiku") {
+        DIRECTORIES_HAIKU
+    } else if cfg!(any(target_os = "linux", target_os = "freebsd")) {
+        DIRECTORIES_LINUX
+    } else if cfg!(target_os = "macos") {
+        DIRECTORIES_MACOS
+    } else if cfg!(target_os = "windows") {
+        DIRECTORIES_WINDOWS
+    } else if cfg!(target_os = "illumos") {
+        DIRECTORIES_ILLUMOS
+    } else {
+        &[]
+    };
+
+    // Search the directories provided by the `libclang` directory patterns.
+    let mut options = MatchOptions::new();
+    options.case_sensitive = false;
+    options.require_literal_separator = true;
+    for directory in directories.iter().rev() {
+        if let Ok(directories) = glob::glob_with(directory, options) {
+            for directory in directories.filter_map(Result::ok).filter(|p| p.is_dir()) {
+                found.extend(search_directories(&directory, filenames));
+            }
+        }
+    }
+
+    found
+}