clang_sys/
support.rs

1// Copyright 2016 Kyle Mayes
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15//! Provides helper functionality.
16
17use std::path::{Path, PathBuf};
18use std::process::Command;
19use std::{env, io};
20
21use glob;
22
23use libc::c_int;
24
25use super::CXVersion;
26
27//================================================
28// Macros
29//================================================
30
31macro_rules! try_opt {
32    ($option:expr) => {{
33        match $option {
34            Some(some) => some,
35            None => return None,
36        }
37    }};
38}
39
40//================================================
41// Structs
42//================================================
43
44/// A `clang` executable.
45#[derive(Clone, Debug)]
46pub struct Clang {
47    /// The path to this `clang` executable.
48    pub path: PathBuf,
49    /// The version of this `clang` executable if it could be parsed.
50    pub version: Option<CXVersion>,
51    /// The directories searched by this `clang` executable for C headers if
52    /// they could be parsed.
53    pub c_search_paths: Option<Vec<PathBuf>>,
54    /// The directories searched by this `clang` executable for C++ headers if
55    /// they could be parsed.
56    pub cpp_search_paths: Option<Vec<PathBuf>>,
57}
58
59impl Clang {
60    fn new(path: impl AsRef<Path>, args: &[String]) -> Self {
61        Self {
62            path: path.as_ref().into(),
63            version: parse_version(path.as_ref()),
64            c_search_paths: parse_search_paths(path.as_ref(), "c", args),
65            cpp_search_paths: parse_search_paths(path.as_ref(), "c++", args),
66        }
67    }
68
69    /// Returns a `clang` executable if one can be found.
70    ///
71    /// If the `CLANG_PATH` environment variable is set, that is the instance of
72    /// `clang` used. Otherwise, a series of directories are searched. First, if
73    /// a path is supplied, that is the first directory searched. Then, the
74    /// directory returned by `llvm-config --bindir` is searched. On macOS
75    /// systems, `xcodebuild -find clang` will next be queried. Last, the
76    /// directories in the system's `PATH` are searched.
77    pub fn find(path: Option<&Path>, args: &[String]) -> Option<Clang> {
78        if let Ok(path) = env::var("CLANG_PATH") {
79            return Some(Clang::new(path, args));
80        }
81
82        let mut paths = vec![];
83        if let Some(path) = path {
84            paths.push(path.into());
85        }
86        if let Ok(path) = run_llvm_config(&["--bindir"]) {
87            if let Some(line) = path.lines().next() {
88                paths.push(line.into());
89            }
90        }
91        if cfg!(target_os = "macos") {
92            if let Ok((path, _)) = run("xcodebuild", &["-find", "clang"]) {
93                if let Some(line) = path.lines().next() {
94                    paths.push(line.into());
95                }
96            }
97        }
98        paths.extend(env::split_paths(&env::var("PATH").unwrap()));
99
100        let default = format!("clang{}", env::consts::EXE_SUFFIX);
101        let versioned = format!("clang-[0-9]*{}", env::consts::EXE_SUFFIX);
102        let patterns = &[&default[..], &versioned[..]];
103        for path in paths {
104            if let Some(path) = find(&path, patterns) {
105                return Some(Clang::new(path, args));
106            }
107        }
108
109        None
110    }
111}
112
113//================================================
114// Functions
115//================================================
116
117/// Returns the first match to the supplied glob patterns in the supplied
118/// directory if there are any matches.
119fn find(directory: &Path, patterns: &[&str]) -> Option<PathBuf> {
120    for pattern in patterns {
121        let pattern = directory.join(pattern).to_string_lossy().into_owned();
122        if let Some(path) = try_opt!(glob::glob(&pattern).ok())
123            .filter_map(|p| p.ok())
124            .next()
125        {
126            if path.is_file() && is_executable(&path).unwrap_or(false) {
127                return Some(path);
128            }
129        }
130    }
131
132    None
133}
134
135#[cfg(unix)]
136fn is_executable(path: &Path) -> io::Result<bool> {
137    use std::ffi::CString;
138    use std::os::unix::ffi::OsStrExt;
139
140    let path = CString::new(path.as_os_str().as_bytes())?;
141    unsafe { Ok(libc::access(path.as_ptr(), libc::X_OK) == 0) }
142}
143
144#[cfg(not(unix))]
145fn is_executable(_: &Path) -> io::Result<bool> {
146    Ok(true)
147}
148
149/// Attempts to run an executable, returning the `stdout` and `stderr` output if
150/// successful.
151fn run(executable: &str, arguments: &[&str]) -> Result<(String, String), String> {
152    Command::new(executable)
153        .args(arguments)
154        .output()
155        .map(|o| {
156            let stdout = String::from_utf8_lossy(&o.stdout).into_owned();
157            let stderr = String::from_utf8_lossy(&o.stderr).into_owned();
158            (stdout, stderr)
159        })
160        .map_err(|e| format!("could not run executable `{}`: {}", executable, e))
161}
162
163/// Runs `clang`, returning the `stdout` and `stderr` output.
164fn run_clang(path: &Path, arguments: &[&str]) -> (String, String) {
165    run(&path.to_string_lossy().into_owned(), arguments).unwrap()
166}
167
168/// Runs `llvm-config`, returning the `stdout` output if successful.
169fn run_llvm_config(arguments: &[&str]) -> Result<String, String> {
170    let config = env::var("LLVM_CONFIG_PATH").unwrap_or_else(|_| "llvm-config".to_string());
171    run(&config, arguments).map(|(o, _)| o)
172}
173
174/// Parses a version number if possible, ignoring trailing non-digit characters.
175fn parse_version_number(number: &str) -> Option<c_int> {
176    number
177        .chars()
178        .take_while(|c| c.is_digit(10))
179        .collect::<String>()
180        .parse()
181        .ok()
182}
183
184/// Parses the version from the output of a `clang` executable if possible.
185fn parse_version(path: &Path) -> Option<CXVersion> {
186    let output = run_clang(path, &["--version"]).0;
187    let start = try_opt!(output.find("version ")) + 8;
188    let mut numbers = try_opt!(output[start..].split_whitespace().next()).split('.');
189    let major = try_opt!(numbers.next().and_then(parse_version_number));
190    let minor = try_opt!(numbers.next().and_then(parse_version_number));
191    let subminor = numbers.next().and_then(parse_version_number).unwrap_or(0);
192    Some(CXVersion {
193        Major: major,
194        Minor: minor,
195        Subminor: subminor,
196    })
197}
198
199/// Parses the search paths from the output of a `clang` executable if possible.
200fn parse_search_paths(path: &Path, language: &str, args: &[String]) -> Option<Vec<PathBuf>> {
201    let mut clang_args = vec!["-E", "-x", language, "-", "-v"];
202    clang_args.extend(args.iter().map(|s| &**s));
203    let output = run_clang(path, &clang_args).1;
204    let start = try_opt!(output.find("#include <...> search starts here:")) + 34;
205    let end = try_opt!(output.find("End of search list."));
206    let paths = output[start..end].replace("(framework directory)", "");
207    Some(
208        paths
209            .lines()
210            .filter(|l| !l.is_empty())
211            .map(|l| Path::new(l.trim()).into())
212            .collect(),
213    )
214}
clang_sys/support.rs

clang_sys/
support.rs
