Add a cargo_metadata option to disable printing

Enable it by default, however

Author: alexcrichton

src/lib.rs

@@ -81,6 +81,7 @@ pub struct Config {
     statik: Option<bool>,
     atleast_version: Option<String>,
     extra_args: Vec<OsString>,
+    cargo_metadata: bool,
 }
 
 #[derive(Debug)]
@@ -253,6 +254,7 @@ impl Config {
             statik: None,
             atleast_version: None,
             extra_args: vec![],
+            cargo_metadata: true,
         }
     }
 
@@ -279,6 +281,13 @@ impl Config {
         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
+    }
+
     /// Deprecated in favor fo the `probe` function
     #[doc(hidden)]
     pub fn find(&self, name: &str) -> Result<Library, String> {
@@ -333,6 +342,12 @@ impl Config {
         }
         cmd
     }
+
+    fn print_metadata(&self, s: &str) {
+        if self.cargo_metadata {
+            println!("cargo:{}", s);
+        }
+    }
 }
 
 impl Library {
@@ -359,12 +374,14 @@ impl Library {
         for &(flag, val) in parts.iter() {
             match flag {
                 "-L" => {
-                    println!("cargo:rustc-link-search=native={}", val);
+                    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" => {
-                    println!("cargo:rustc-link-search=framework={}", val);
+                    let meta = format!("rustc-link-search=framework={}", val);
+                    config.print_metadata(&meta);
                     self.framework_paths.push(PathBuf::from(val));
                 }
                 "-I" => {
@@ -373,9 +390,11 @@ impl Library {
                 "-l" => {
                     self.libs.push(val.to_string());
                     if statik && !is_system(val, &dirs) {
-                        println!("cargo:rustc-link-lib=static={}", val);
+                        let meta = format!("rustc-link-lib=static={}", val);
+                        config.print_metadata(&meta);
                     } else {
-                        println!("cargo:rustc-link-lib={}", val);
+                        let meta = format!("rustc-link-lib={}", val);
+                        config.print_metadata(&meta);
                     }
                 }
                 _ => {}
@@ -384,9 +403,12 @@ impl Library {
 
         let mut iter = output.split(' ');
         while let Some(part) = iter.next() {
-            if part != "-framework" { continue }
+            if part != "-framework" {
+                continue
+            }
             if let Some(lib) = iter.next() {
-                println!("cargo:rustc-link-lib=framework={}", lib);
+                let meta = format!("cargo:rustc-link-lib=framework={}", lib);
+                config.print_metadata(&meta);
                 self.frameworks.push(lib.to_string());
             }
         }