Add a new Target::Path variant for (absolute) *.json paths

src/main.rs

@@ -15,7 +15,7 @@ use std::hash::{Hash, Hasher};
 use std::io::Write;
 use std::path::{Path, PathBuf};
 use std::process::ExitStatus;
-use std::{env, io, process};
+use std::{env, ffi, io, process};
 
 use rustc_version::Channel;
 
@@ -56,9 +56,16 @@ impl CompilationMode {
         Ok(())
     }
 
-    fn triple(&self) -> &str {
+    fn triple(&self) -> String {
         match *self {
             CompilationMode::Cross(ref target) => target.triple(),
+            CompilationMode::Native(ref triple) => triple.to_owned(),
+        }
+    }
+
+    fn target_arg(&self) -> &str {
+        match *self {
+            CompilationMode::Cross(ref target) => target.target_arg(),
             CompilationMode::Native(ref triple) => triple,
         }
     }
@@ -151,11 +158,9 @@ 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`."
-                )
+            let path = Path::new(triple);
+            if path.extension() == Some(ffi::OsStr::new("json")) {
+                Some(CompilationMode::Cross(Target::new_from_path(path, &cd)?))
             } else if triple == meta.host {
                 Some(CompilationMode::Native(meta.host.clone()))
             } else {
@@ -175,7 +180,7 @@ fn run() -> Result<ExitStatus> {
 
         if let Some(cmode) = cmode {
             let home = xargo::home(&cmode)?;
-            let rustflags = cargo::rustflags(config.as_ref(), cmode.triple())?;
+            let rustflags = cargo::rustflags(config.as_ref(), &cmode.triple())?;
 
             sysroot::update(
                 &cmode,

src/rustc.rs

@@ -112,6 +112,7 @@ impl Sysroot {
 pub enum Target {
     Builtin { triple: String },
     Custom { json: PathBuf, triple: String },
+    Path { path: PathBuf },
 }
 
 impl Target {
@@ -148,10 +149,38 @@ impl Target {
         }
     }
 
-    pub fn triple(&self) -> &str {
+    pub fn new_from_path(path: &Path, cd: &CurrentDirectory) -> Result<Target> {
+        let json = cd.path().join(path).canonicalize().map_err(|err| {
+            format!("target path {:?} does not point to a valid file: {:?}", path, err)
+        })?;
+        Ok(Target::Path { path: json })
+    }
+
+    pub fn triple(&self) -> String {
+        use std::hash::{Hash, Hasher};
+        use std::collections::hash_map::DefaultHasher;
+
+        match *self {
+            Target::Builtin { ref triple } => triple.clone(),
+            Target::Custom { ref triple, .. } => triple.clone(),
+            Target::Path { ref path } => {
+                let stem = path.file_stem().expect("target path must not be empty").to_str()
+                    .expect("target path must be valid unicode");
+                let mut hasher = DefaultHasher::new();
+                path.hash(&mut hasher);
+                let hash = hasher.finish();
+                format!("{}-{}", stem, hash)
+            }
+        }
+    }
+
+    pub fn target_arg(&self) -> &str {
         match *self {
             Target::Builtin { ref triple } => triple,
             Target::Custom { ref triple, .. } => triple,
+            Target::Path { ref path } => {
+                path.to_str().expect("target path contains invalid unicode")
+            },
         }
     }
 

src/sysroot.rs

@@ -46,7 +46,7 @@ name = "sysroot"
 version = "0.0.0"
 "#;
 
-    let rustlib = home.lock_rw(cmode.triple())?;
+    let rustlib = home.lock_rw(&cmode.triple())?;
     rustlib
         .remove_siblings()
         .chain_err(|| format!("couldn't clear {}", rustlib.path().display()))?;
@@ -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.target_arg()]);
 
             if verbose {
                 cmd.arg("-v");
@@ -155,7 +155,7 @@ version = "0.0.0"
 
 fn old_hash(cmode: &CompilationMode, home: &Home) -> Result<Option<u64>> {
     // FIXME this should be `lock_ro`
-    let lock = home.lock_rw(cmode.triple())?;
+    let lock = home.lock_rw(&cmode.triple())?;
     let hfile = lock.parent().join(".hash");
 
     if hfile.exists() {
@@ -213,7 +213,7 @@ pub fn update(
     let ctoml = cargo::toml(root)?;
     let xtoml = xargo::toml(root)?;
 
-    let blueprint = Blueprint::from(xtoml.as_ref(), cmode.triple(), root, &src)?;
+    let blueprint = Blueprint::from(xtoml.as_ref(), &cmode.triple(), root, &src)?;
 
     let hash = hash(cmode, &blueprint, rustflags, &ctoml, meta)?;
 

src/xargo.rs

@@ -29,7 +29,7 @@ pub fn run(
     if args.subcommand() == Some(Subcommand::Doc) {
         cmd.env(
             "RUSTDOCFLAGS",
-            cargo::rustdocflags(config, cmode.triple())?.for_xargo(home),
+            cargo::rustdocflags(config, &cmode.triple())?.for_xargo(home),
         );
     }
 
@@ -39,7 +39,7 @@ pub fn run(
     }
     cmd.env("RUSTFLAGS", flags);
 
-    let locks = (home.lock_ro(&meta.host), home.lock_ro(cmode.triple()));
+    let locks = (home.lock_ro(&meta.host), home.lock_ro(&cmode.triple()));
 
     let status = cmd.run_and_get_status(verbose)?;