Support absolute target JSON paths

src/main.rs

@@ -56,13 +56,22 @@ impl CompilationMode {
         Ok(())
     }
 
+    /// Returns the condensed target triple (removes any `.json` extension and path components).
     fn triple(&self) -> &str {
         match *self {
             CompilationMode::Cross(ref target) => target.triple(),
             CompilationMode::Native(ref triple) => triple,
         }
     }
 
+    /// Returns the original target triple passed to xargo (perhaps with `.json` extension).
+    fn orig_triple(&self) -> &str {
+        match *self {
+            CompilationMode::Cross(ref target) => target.orig_triple(),
+            CompilationMode::Native(ref triple) => triple,
+        }
+    }
+
     fn is_native(&self) -> bool {
         match *self {
             CompilationMode::Native(_) => true,
@@ -151,12 +160,7 @@ fn run() -> Result<ExitStatus> {
         };
 
         let cmode = if let Some(triple) = args.target() {
-            if Path::new(triple).is_file() {
-                bail!(
-                    "Xargo doesn't support files as an argument to --target. \
-                     Use `--target foo` instead of `--target foo.json`."
-                )
-            } else if triple == meta.host {
+            if triple == meta.host {
                 Some(CompilationMode::Native(meta.host.clone()))
             } else {
                 Target::new(triple, &cd, verbose)?.map(CompilationMode::Cross)

src/rustc.rs

@@ -111,7 +111,7 @@ impl Sysroot {
 #[derive(Debug)]
 pub enum Target {
     Builtin { triple: String },
-    Custom { json: PathBuf, triple: String },
+    Custom { json: PathBuf, triple: String, orig_triple: String },
 }
 
 impl Target {
@@ -121,13 +121,24 @@ impl Target {
         if rustc::targets(verbose)?.iter().any(|t| t == &triple) {
             Ok(Some(Target::Builtin { triple: triple }))
         } else {
+            let json = PathBuf::from(&triple);
+            if json.exists() {
+                let file_stem = match json.file_stem().and_then(|stem| stem.to_str()) {
+                    Some(stem) => stem.into(),
+                    None => {
+                        bail!("target file name {:?} is empty or contains invalid unicode", json)
+                    }
+                };
+                return Ok(Some(Target::Custom { json, triple: file_stem, orig_triple: triple }))
+            }
             let mut json = cd.path().join(&triple);
             json.set_extension("json");
 
             if json.exists() {
                 return Ok(Some(Target::Custom {
                     json: json,
-                    triple: triple,
+                    triple: triple.clone(),
+                    orig_triple: triple,
                 }));
             } else {
                 if let Some(p) = env::var_os("RUST_TARGET_PATH") {
@@ -138,7 +149,8 @@ impl Target {
                     if json.exists() {
                         return Ok(Some(Target::Custom {
                             json: json,
-                            triple: triple,
+                            triple: triple.clone(),
+                            orig_triple: triple,
                         }));
                     }
                 }
@@ -148,13 +160,22 @@ impl Target {
         }
     }
 
+    /// Returns the condensed target triple (removes any `.json` extension and path components).
     pub fn triple(&self) -> &str {
         match *self {
             Target::Builtin { ref triple } => triple,
             Target::Custom { ref triple, .. } => triple,
         }
     }
 
+    /// Returns the original target triple passed to xargo (perhaps with `.json` extension).
+    pub fn orig_triple(&self) -> &str {
+        match *self {
+            Target::Builtin { ref triple } => triple,
+            Target::Custom { ref orig_triple, .. } => orig_triple,
+        }
+    }
+
     pub fn hash<H>(&self, hasher: &mut H) -> Result<()>
     where
         H: Hasher,

src/sysroot.rs

@@ -124,7 +124,7 @@ version = "0.0.0"
             }
             cmd.arg("--manifest-path");
             cmd.arg(td.join("Cargo.toml"));
-            cmd.args(&["--target", cmode.triple()]);
+            cmd.args(&["--target", cmode.orig_triple()]);
 
             if verbose {
                 cmd.arg("-v");