Merge pull request #921 from eonil/master

Find path prefix to OpenSSL installed by Homebrew better.

2 files changed, 41 insertions, 7 deletions

diff --git a/README.md b/README.md
index 33727d0d..16155fbd 100644
--- a/README.md
+++ b/README.md
@@ -48,25 +48,25 @@ make -j$(nproc)
 make install
 ```
 
-### OSX
+### macOS
 
-Although OpenSSL 0.9.8 is preinstalled on OSX this library is being phased out
-of OSX and this crate also does not support that version of OpenSSL. To use this
-crate on OSX you'll need to install OpenSSL via some alternate means, typically
+Although OpenSSL 0.9.8 is preinstalled on macOS this library is being phased out
+of macOS and this crate also does not support that version of OpenSSL. To use this
+crate on macOS you'll need to install OpenSSL via some alternate means, typically
 Homebrew:
 
 ```bash
 brew install openssl
 ```
 
-Occasionally an update of XCode or MacOS will cause the linker to fail after compilation, to rectify this you may want to try and run:
+Occasionally an update of XCode or macOS will cause the linker to fail after compilation, to rectify this you may want to try and run:
 
 ```bash
 xcode-select --install
 ```
 
-If Homebrew is installed to the default location of `/usr/local`, OpenSSL will be
-automatically detected.
+If you're using latest version of Homebrew which supports `--prefix` command,
+OpenSSL will be automatically detected.
 
 ### Windows MSVC
 
diff --git a/openssl-sys/build.rs b/openssl-sys/build.rs
index 0b8341fa..c5630556 100644
--- a/openssl-sys/build.rs
+++ b/openssl-sys/build.rs
@@ -104,6 +104,8 @@ fn find_openssl_dir(target: &str) -> OsString {
     let host = env::var("HOST").unwrap();
 
     if host == target && target.contains("apple-darwin") {
+        // Check up default Homebrew installation location first
+        // for quick resolution if possible.
         let homebrew = Path::new("/usr/local/opt/[email protected]");
         if homebrew.exists() {
             return homebrew.to_path_buf().into();
@@ -112,6 +114,22 @@ fn find_openssl_dir(target: &str) -> OsString {
         if homebrew.exists() {
             return homebrew.to_path_buf().into();
         }
+        // Calling `brew --prefix <package>` command usually slow and 
+        // takes seconds, and will be used only as a last resort.
+        let output = execute_command_and_get_output("brew", &["--prefix", "[email protected]"]);
+        if let Some(ref output) = output {
+            let homebrew = Path::new(&output);
+            if homebrew.exists() {
+                return homebrew.to_path_buf().into();
+            }
+        }
+        let output = execute_command_and_get_output("brew", &["--prefix", "openssl"]);
+        if let Some(ref output) = output {
+            let homebrew = Path::new(&output);
+            if homebrew.exists() {
+                return homebrew.to_path_buf().into();
+            }
+        }
     }
 
     try_pkg_config();
@@ -548,3 +566,19 @@ fn determine_mode(libdir: &Path, libs: &[&str]) -> &'static str {
     // practices with security libs", let's link dynamically.
     "dylib"
 }
+
+
+
+fn execute_command_and_get_output(cmd: &str, args: &[&str]) -> Option<String> {
+    let out = Command::new(cmd).args(args).output();
+    if let Ok(ref r1) = out {
+        if r1.status.success() {
+            let r2 = String::from_utf8(r1.stdout.clone());
+            if let Ok(r3) = r2 {
+                return Some(r3.trim().to_string());
+            } 
+        }
+    }
+    return None;
+}
+