Switch over to using find-folly crate

examples/folly/Cargo.toml

@@ -21,5 +21,4 @@ features = ["thread-pool"]
 
 [build-dependencies]
 cxx-build = "1"
-pkg-config = "0.3"
-shlex = "1"
+find-folly = "0.1"

examples/folly/build.rs

@@ -1,108 +1,9 @@
 // cxx-async/examples/folly/build.rs
 
-use pkg_config::Config;
-use shlex::Shlex;
-use std::path::{Path, PathBuf};
-use std::process::Command;
-use std::str::FromStr;
+use find_folly;
 
 fn main() {
-    // Folly's `.pc` file is missing the `fmt` and `gflags` dependencies. Find them here.
-    Config::new()
-        .statik(true)
-        .probe("fmt")
-        .expect("No `fmt` package found!");
-    Config::new()
-        .statik(true)
-        .probe("gflags")
-        .expect("No `gflags` package found!");
-
-    // Unfortunately, the `pkg-config` crate doesn't successfully parse some of Folly's
-    // dependencies, because it passes the raw `.so` files instead of using `-l` flags. So call
-    // `pkg-config` manually.
-    let mut lib_dirs = vec![];
-    let output = Command::new("pkg-config")
-        .args(&["--static", "--libs", "libfolly"])
-        .output()
-        .expect("Failed to execute `pkg-config` to find Folly!");
-    let output = String::from_utf8(output.stdout).expect("`pkg-config --libs` wasn't UTF-8!");
-    for arg in Shlex::new(&output) {
-        if arg.starts_with('-') {
-            if let Some(rest) = arg.strip_prefix("-L") {
-                lib_dirs.push(PathBuf::from(rest));
-            } else if let Some(rest) = arg.strip_prefix("-l") {
-                println!("cargo:rustc-link-lib={}", rest);
-            }
-            continue;
-        }
-
-        let path = PathBuf::from_str(&arg).unwrap();
-        let (parent, lib_name) = match (path.parent(), path.file_stem()) {
-            (Some(parent), Some(lib_name)) => (parent, lib_name),
-            _ => continue,
-        };
-        let lib_name = lib_name.to_string_lossy();
-        if let Some(rest) = lib_name.strip_prefix("lib") {
-            println!("cargo:rustc-link-search={}", parent.display());
-            println!("cargo:rustc-link-lib={}", rest);
-        }
-    }
-
-    // Unfortunately, just like `fmt` and `gflags`, Folly's `.pc` file doesn't contain a link flag
-    // for `boost_context`. What's worse, the name varies based on different systems
-    // (`libboost_context.a` vs.  `libboost_context-mt.a`). So find that library manually. We assume
-    // it's in the same directory as the Folly installation itself.
-    let mut found_boost_context = false;
-    for lib_dir in &lib_dirs {
-        println!("cargo:rustc-link-search={}", lib_dir.display());
-
-        if found_boost_context {
-            continue;
-        }
-        for possible_lib_name in &["boost_context", "boost_context-mt"] {
-            let mut lib_dir = (*lib_dir).clone();
-            lib_dir.push(&format!("lib{}.a", possible_lib_name));
-            if !lib_dir.exists() {
-                continue;
-            }
-            println!("cargo:rustc-link-lib={}", possible_lib_name);
-            found_boost_context = true;
-            break;
-        }
-    }
-    if !found_boost_context {
-        panic!(
-            "Could not find `boost_context`. Make sure either `libboost_context.a` or \
-            `libboost_context-mt.a` is located in the same directory as Folly."
-        )
-    }
-
-    let output = Command::new("pkg-config")
-        .args(&["--static", "--cflags", "libfolly"])
-        .output()
-        .expect("Failed to execute `pkg-config` to find Folly!");
-    let output = String::from_utf8(output.stdout).expect("`pkg-config --libs` wasn't UTF-8!");
-
-    let (mut include_dirs, mut other_cflags) = (vec![], vec![]);
-    for arg in output.split_whitespace() {
-        if let Some(rest) = arg.strip_prefix("-I") {
-            let path = Path::new(rest);
-            if path.starts_with("/Library/Developer/CommandLineTools/SDKs")
-                && path.ends_with("usr/include")
-            {
-                // Change any attempt to specify system headers from `-I` to `-isysroot`. `-I` is
-                // not the proper way to include a system header and will cause compilation failures
-                // on macOS Catalina.
-                //
-                // Pop off the trailing `usr/include`.
-                let sysroot = path.parent().unwrap().parent().unwrap();
-                other_cflags.push("-isysroot".to_owned());
-                other_cflags.push(sysroot.to_string_lossy().into_owned());
-            } else {
-                include_dirs.push(path.to_owned());
-            }
-        }
-    }
+    let folly = find_folly::probe_folly().expect("Couldn't find the Folly library!");
 
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=include/folly_example.h");
@@ -114,9 +15,9 @@ fn main() {
         .include("include")
         .include("../common/include")
         .include("../../cxx-async/include")
-        .includes(&include_dirs);
-    for other_cflag in other_cflags {
-        build.flag(&other_cflag);
+        .includes(&folly.include_paths);
+    for other_cflag in &folly.other_cflags {
+        build.flag(other_cflag);
     }
     build.compile("folly_example");
 }