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Diffstat (limited to 'pkg-config/src/lib.rs')
| -rw-r--r-- | pkg-config/src/lib.rs | 510 |
1 files changed, 510 insertions, 0 deletions
diff --git a/pkg-config/src/lib.rs b/pkg-config/src/lib.rs new file mode 100644 index 0000000..c88bd34 --- /dev/null +++ b/pkg-config/src/lib.rs @@ -0,0 +1,510 @@ +//! A build dependency for Cargo libraries to find system artifacts through the +//! `pkg-config` utility. +//! +//! This library will shell out to `pkg-config` as part of build scripts and +//! probe the system to determine how to link to a specified library. The +//! `Config` structure serves as a method of configuring how `pkg-config` is +//! invoked in a builder style. +//! +//! A number of environment variables are available to globally configure how +//! this crate will invoke `pkg-config`: +//! +//! * `PKG_CONFIG_ALLOW_CROSS` - if this variable is not set, then `pkg-config` +//! will automatically be disabled for all cross compiles. +//! * `FOO_NO_PKG_CONFIG` - if set, this will disable running `pkg-config` when +//! probing for the library named `foo`. +//! +//! There are also a number of environment variables which can configure how a +//! library is linked to (dynamically vs statically). These variables control +//! whether the `--static` flag is passed. Note that this behavior can be +//! overridden by configuring explicitly on `Config`. The variables are checked +//! in the following order: +//! +//! * `FOO_STATIC` - pass `--static` for the library `foo` +//! * `FOO_DYNAMIC` - do not pass `--static` for the library `foo` +//! * `PKG_CONFIG_ALL_STATIC` - pass `--static` for all libraries +//! * `PKG_CONFIG_ALL_DYNAMIC` - do not pass `--static` for all libraries +//! +//! After running `pkg-config` all appropriate Cargo metadata will be printed on +//! stdout if the search was successful. +//! +//! # Example +//! +//! Find the system library named `foo`, with minimum version 1.2.3: +//! +//! ```no_run +//! extern crate pkg_config; +//! +//! fn main() { +//! pkg_config::Config::new().atleast_version("1.2.3").probe("foo").unwrap(); +//! } +//! ``` +//! +//! Find the system library named `foo`, with no version requirement (not +//! recommended): +//! +//! ```no_run +//! extern crate pkg_config; +//! +//! fn main() { +//! pkg_config::probe_library("foo").unwrap(); +//! } +//! ``` +//! +//! Configure how library `foo` is linked to. +//! +//! ```no_run +//! extern crate pkg_config; +//! +//! fn main() { +//! pkg_config::Config::new().atleast_version("1.2.3").statik(true).probe("foo").unwrap(); +//! } +//! ``` + +#![doc(html_root_url = "http://alexcrichton.com/pkg-config-rs")] +#![cfg_attr(test, deny(warnings))] + +use std::ascii::AsciiExt; +use std::env; +use std::error; +use std::ffi::{OsStr, OsString}; +use std::fmt; +use std::fs; +use std::io; +use std::path::{PathBuf, Path}; +use std::process::{Command, Output}; +use std::str; + +pub fn target_supported() -> bool { + let target = env::var("TARGET").unwrap_or(String::new()); + let host = env::var("HOST").unwrap_or(String::new()); + + // Only use pkg-config in host == target situations by default (allowing an + // override) and then also don't use pkg-config on MSVC as it's really not + // meant to work there but when building MSVC code in a MSYS shell we may be + // able to run pkg-config anyway. + (host == target || env::var_os("PKG_CONFIG_ALLOW_CROSS").is_some()) && + !target.contains("msvc") +} + +#[derive(Clone)] +pub struct Config { + statik: Option<bool>, + atleast_version: Option<String>, + extra_args: Vec<OsString>, + cargo_metadata: bool, + print_system_libs: bool, +} + +#[derive(Debug)] +pub struct Library { + pub libs: Vec<String>, + pub link_paths: Vec<PathBuf>, + pub frameworks: Vec<String>, + pub framework_paths: Vec<PathBuf>, + pub include_paths: Vec<PathBuf>, + pub version: String, + _priv: (), +} + +/// Represents all reasons `pkg-config` might not succeed or be run at all. +pub enum Error { + /// Aborted because of `*_NO_PKG_CONFIG` environment variable. + /// + /// Contains the name of the responsible environment variable. + EnvNoPkgConfig(String), + + /// Cross compilation detected. + /// + /// Override with `PKG_CONFIG_ALLOW_CROSS=1`. + CrossCompilation, + + /// Attempted to compile using the MSVC ABI build + MSVC, + + /// Failed to run `pkg-config`. + /// + /// Contains the command and the cause. + Command { command: String, cause: io::Error }, + + /// `pkg-config` did not exit sucessfully. + /// + /// Contains the command and output. + Failure { command: String, output: Output }, + + #[doc(hidden)] + // please don't match on this, we're likely to add more variants over time + __Nonexhaustive, +} + +impl error::Error for Error { + fn description(&self) -> &str { + match *self { + Error::EnvNoPkgConfig(_) => "pkg-config requested to be aborted", + Error::CrossCompilation => { + "pkg-config doesn't handle cross compilation. \ + Use PKG_CONFIG_ALLOW_CROSS=1 to override" + } + Error::MSVC => "pkg-config is incompatible with the MSVC ABI build.", + Error::Command { .. } => "failed to run pkg-config", + Error::Failure { .. } => "pkg-config did not exit sucessfully", + Error::__Nonexhaustive => panic!(), + } + } + + fn cause(&self) -> Option<&error::Error> { + match *self { + Error::Command { ref cause, .. } => Some(cause), + _ => None, + } + } +} + +// Workaround for temporary lack of impl Debug for Output in stable std +struct OutputDebugger<'a>(&'a Output); + +// Lifted from 1.7 std +impl<'a> fmt::Debug for OutputDebugger<'a> { + fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { + let stdout_utf8 = str::from_utf8(&self.0.stdout); + let stdout_debug: &fmt::Debug = match stdout_utf8 { + Ok(ref str) => str, + Err(_) => &self.0.stdout + }; + + let stderr_utf8 = str::from_utf8(&self.0.stderr); + let stderr_debug: &fmt::Debug = match stderr_utf8 { + Ok(ref str) => str, + Err(_) => &self.0.stderr + }; + + fmt.debug_struct("Output") + .field("status", &self.0.status) + .field("stdout", stdout_debug) + .field("stderr", stderr_debug) + .finish() + } +} + +// Workaround for temporary lack of impl Debug for Output in stable std, continued +impl fmt::Debug for Error { + fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { + match *self { + Error::EnvNoPkgConfig(ref name) => { + f.debug_tuple("EnvNoPkgConfig") + .field(name) + .finish() + } + Error::CrossCompilation => write!(f, "CrossCompilation"), + Error::MSVC => write!(f, "MSVC"), + Error::Command { ref command, ref cause } => { + f.debug_struct("Command") + .field("command", command) + .field("cause", cause) + .finish() + } + Error::Failure { ref command, ref output } => { + f.debug_struct("Failure") + .field("command", command) + .field("output", &OutputDebugger(output)) + .finish() + } + Error::__Nonexhaustive => panic!(), + } + } +} + +impl fmt::Display for Error { + fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> { + match *self { + Error::EnvNoPkgConfig(ref name) => { + write!(f, "Aborted because {} is set", name) + } + Error::CrossCompilation => { + write!(f, "Cross compilation detected. \ + Use PKG_CONFIG_ALLOW_CROSS=1 to override") + } + Error::MSVC => { + write!(f, "MSVC target detected. If you are using the MSVC ABI \ + rust build, please use the GNU ABI build instead.") + } + Error::Command { ref command, ref cause } => { + write!(f, "Failed to run `{}`: {}", command, cause) + } + Error::Failure { ref command, ref output } => { + let stdout = str::from_utf8(&output.stdout).unwrap(); + let stderr = str::from_utf8(&output.stderr).unwrap(); + try!(write!(f, "`{}` did not exit successfully: {}", command, output.status)); + if !stdout.is_empty() { + try!(write!(f, "\n--- stdout\n{}", stdout)); + } + if !stderr.is_empty() { + try!(write!(f, "\n--- stderr\n{}", stderr)); + } + Ok(()) + } + Error::__Nonexhaustive => panic!(), + } + } +} + +/// Deprecated in favor of the probe_library function +#[doc(hidden)] +pub fn find_library(name: &str) -> Result<Library, String> { + probe_library(name).map_err(|e| e.to_string()) +} + +/// Simple shortcut for using all default options for finding a library. +pub fn probe_library(name: &str) -> Result<Library, Error> { + Config::new().probe(name) +} + +/// Run `pkg-config` to get the value of a variable from a package using +/// --variable. +pub fn get_variable(package: &str, variable: &str) -> Result<String, Error> { + let arg = format!("--variable={}", variable); + let cfg = Config::new(); + Ok(try!(run(cfg.command(package, &[&arg]))).trim_right().to_owned()) +} + +impl Config { + /// Creates a new set of configuration options which are all initially set + /// to "blank". + pub fn new() -> Config { + Config { + statik: None, + atleast_version: None, + extra_args: vec![], + print_system_libs: true, + cargo_metadata: true, + } + } + + /// Indicate whether the `--static` flag should be passed. + /// + /// This will override the inference from environment variables described in + /// the crate documentation. + pub fn statik(&mut self, statik: bool) -> &mut Config { + self.statik = Some(statik); + self + } + + /// Indicate that the library must be at least version `vers`. + pub fn atleast_version(&mut self, vers: &str) -> &mut Config { + self.atleast_version = Some(vers.to_string()); + self + } + + /// Add an argument to pass to pkg-config. + /// + /// It's placed after all of the arguments generated by this library. + pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Config { + self.extra_args.push(arg.as_ref().to_os_string()); + self + } + + /// Define whether metadata should be emitted for cargo allowing it to + /// automatically link the binary. Defaults to `true`. + pub fn cargo_metadata(&mut self, cargo_metadata: bool) -> &mut Config { + self.cargo_metadata = cargo_metadata; + self + } + + /// Enable or disable the `PKG_CONFIG_ALLOW_SYSTEM_LIBS` environment + /// variable. + /// + /// This env var is enabled by default. + pub fn print_system_libs(&mut self, print: bool) -> &mut Config { + self.print_system_libs = print; + self + } + + /// Deprecated in favor fo the `probe` function + #[doc(hidden)] + pub fn find(&self, name: &str) -> Result<Library, String> { + self.probe(name).map_err(|e| e.to_string()) + } + + /// Run `pkg-config` to find the library `name`. + /// + /// This will use all configuration previously set to specify how + /// `pkg-config` is run. + pub fn probe(&self, name: &str) -> Result<Library, Error> { + let abort_var_name = format!("{}_NO_PKG_CONFIG", envify(name)); + if env::var_os(&abort_var_name).is_some() { + return Err(Error::EnvNoPkgConfig(abort_var_name)) + } else if !target_supported() { + if env::var("TARGET").unwrap_or(String::new()).contains("msvc") { + return Err(Error::MSVC); + } + else { + return Err(Error::CrossCompilation); + } + } + + let mut library = Library::new(); + + let output = try!(run(self.command(name, &["--libs", "--cflags"]))); + library.parse_libs_cflags(name, &output, self); + + let output = try!(run(self.command(name, &["--modversion"]))); + library.parse_modversion(&output); + + Ok(library) + } + + /// Deprecated in favor of the top level `get_variable` function + #[doc(hidden)] + pub fn get_variable(package: &str, variable: &str) -> Result<String, String> { + get_variable(package, variable).map_err(|e| e.to_string()) + } + + fn is_static(&self, name: &str) -> bool { + self.statik.unwrap_or_else(|| infer_static(name)) + } + + fn command(&self, name: &str, args: &[&str]) -> Command { + let exe = env::var("PKG_CONFIG").unwrap_or(String::from("pkg-config")); + let mut cmd = Command::new(exe); + if self.is_static(name) { + cmd.arg("--static"); + } + cmd.args(args) + .args(&self.extra_args); + + if self.print_system_libs { + cmd.env("PKG_CONFIG_ALLOW_SYSTEM_LIBS", "1"); + } + if let Some(ref version) = self.atleast_version { + cmd.arg(&format!("{} >= {}", name, version)); + } else { + cmd.arg(name); + } + cmd + } + + fn print_metadata(&self, s: &str) { + if self.cargo_metadata { + println!("cargo:{}", s); + } + } +} + +impl Library { + fn new() -> Library { + Library { + libs: Vec::new(), + link_paths: Vec::new(), + include_paths: Vec::new(), + frameworks: Vec::new(), + framework_paths: Vec::new(), + version: String::new(), + _priv: (), + } + } + + fn parse_libs_cflags(&mut self, name: &str, output: &str, config: &Config) { + let parts = output.trim_right() + .split(' ') + .filter(|l| l.len() > 2) + .map(|arg| (&arg[0..2], &arg[2..])) + .collect::<Vec<_>>(); + + let mut dirs = Vec::new(); + let statik = config.is_static(name); + for &(flag, val) in parts.iter() { + match flag { + "-L" => { + let meta = format!("rustc-link-search=native={}", val); + config.print_metadata(&meta); + dirs.push(PathBuf::from(val)); + self.link_paths.push(PathBuf::from(val)); + } + "-F" => { + let meta = format!("rustc-link-search=framework={}", val); + config.print_metadata(&meta); + self.framework_paths.push(PathBuf::from(val)); + } + "-I" => { + self.include_paths.push(PathBuf::from(val)); + } + "-l" => { + self.libs.push(val.to_string()); + if statik && !is_system(val, &dirs) { + let meta = format!("rustc-link-lib=static={}", val); + config.print_metadata(&meta); + } else { + let meta = format!("rustc-link-lib={}", val); + config.print_metadata(&meta); + } + } + _ => {} + } + } + + let mut iter = output.trim_right().split(' '); + while let Some(part) = iter.next() { + if part != "-framework" { + continue + } + if let Some(lib) = iter.next() { + let meta = format!("rustc-link-lib=framework={}", lib); + config.print_metadata(&meta); + self.frameworks.push(lib.to_string()); + } + } + } + + fn parse_modversion(&mut self, output: &str) { + self.version.push_str(output.trim()); + } +} + +fn infer_static(name: &str) -> bool { + let name = envify(name); + if env::var_os(&format!("{}_STATIC", name)).is_some() { + true + } else if env::var_os(&format!("{}_DYNAMIC", name)).is_some() { + false + } else if env::var_os("PKG_CONFIG_ALL_STATIC").is_some() { + true + } else if env::var_os("PKG_CONFIG_ALL_DYNAMIC").is_some() { + false + } else { + false + } +} + +fn envify(name: &str) -> String { + name.chars().map(|c| c.to_ascii_uppercase()).map(|c| { + if c == '-' {'_'} else {c} + }).collect() +} + +fn is_system(name: &str, dirs: &[PathBuf]) -> bool { + let libname = format!("lib{}.a", name); + let root = Path::new("/usr"); + !dirs.iter().any(|d| { + !d.starts_with(root) && fs::metadata(&d.join(&libname)).is_ok() + }) +} + +fn run(mut cmd: Command) -> Result<String, Error> { + match cmd.output() { + Ok(output) => { + if output.status.success() { + let stdout = String::from_utf8(output.stdout).unwrap(); + Ok(stdout) + } else { + Err(Error::Failure { + command: format!("{:?}", cmd), + output: output, + }) + } + } + Err(cause) => Err(Error::Command { + command: format!("{:?}", cmd), + cause: cause, + }), + } +} |