initial commit

.gitignore

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+target
+Cargo.lock

Cargo.toml

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+[package]
+name = "cargo_metadata"
+version = "0.1.0"
+authors = ["Oliver Schneider <git-spam-no-reply9815368754983@oli-obk.de>"]
+repository = "https://github.com/oli-obk/cargo_metadata"
+description = "structured access to the output of `cargo metadata`"
+license = "MIT"
+
+[dependencies]
+serde = "0.9.0-rc3"
+serde_json = "0.9.0-rc2"
+serde_derive = "0.9.0-rc3"

src/lib.rs

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+#![deny(missing_docs)]
+//! Structured access to the output of `cargo metadata`
+//! Usually used from within a `cargo-*` executable
+//!
+//! ```rust
+//! let manifest_path_arg = std::env::args().skip(2).find(|val| val.starts_with("--manifest-path="));
+//! let mut metadata = cargo::metadata(manifest_path_arg.as_ref().map(AsRef::as_ref)).unwrap();
+//! ```
+
+extern crate serde;
+extern crate serde_json;
+#[macro_use] extern crate serde_derive;
+
+use std::collections::HashMap;
+use std::process::Command;
+use std::str::{from_utf8, Utf8Error};
+use std::io;
+
+#[derive(Deserialize, Debug)]
+/// Starting point for metadata returned by `cargo metadata`
+pub struct Metadata {
+    /// A list of all crates referenced by this crate (and the crate itself)
+    pub packages: Vec<Package>,
+    resolve: Option<()>,
+    version: usize,
+}
+
+#[derive(Deserialize, Debug)]
+/// A crate
+pub struct Package {
+    /// Name as given in the `Cargo.toml`
+    pub name: String,
+    /// Version given in the `Cargo.toml`
+    pub version: String,
+    id: String,
+    source: Option<String>,
+    /// List of dependencies of this particular package
+    pub dependencies: Vec<Dependency>,
+    /// Targets provided by the crate (lib, bin, example, test, ...)
+    pub targets: Vec<Target>,
+    features: HashMap<String, Vec<String>>,
+    /// path containing the `Cargo.toml`
+    pub manifest_path: String,
+}
+
+#[derive(Deserialize, Debug)]
+/// A dependency of the main crate
+pub struct Dependency {
+    /// Name as given in the `Cargo.toml`
+    pub name: String,
+    source: Option<String>,
+    /// Whether this is required or optional
+    pub req: String,
+    kind: Option<String>,
+    optional: bool,
+    uses_default_features: bool,
+    features: Vec<String>,
+    target: Option<String>,
+}
+
+#[derive(Deserialize, Debug)]
+/// A single target (lib, bin, example, ...) provided by a crate
+pub struct Target {
+    /// Name as given in the `Cargo.toml` or generated from the file name
+    pub name: String,
+    /// Kind of target ("bin", "example", "test", "bench", "lib")
+    pub kind: Vec<String>,
+    src_path: String,
+}
+
+#[derive(Debug)]
+/// Possible errors that can occur during metadata parsing.
+pub enum Error {
+    /// Error during execution of `cargo metadata`
+    Io(io::Error),
+    /// Output of `cargo metadata` was not valid utf8
+    Utf8(Utf8Error),
+    /// Deserialization error (structure of json did not match expected structure)
+    Json(serde_json::Error),
+}
+
+impl From<io::Error> for Error {
+    fn from(err: io::Error) -> Self {
+        Error::Io(err)
+    }
+}
+impl From<Utf8Error> for Error {
+    fn from(err: Utf8Error) -> Self {
+        Error::Utf8(err)
+    }
+}
+impl From<serde_json::Error> for Error {
+    fn from(err: serde_json::Error) -> Self {
+        Error::Json(err)
+    }
+}
+
+/// The main entry point to obtaining metadata
+pub fn metadata(manifest_path_arg: Option<&str>) -> Result<Metadata, Error> {
+    let mut cmd = Command::new("cargo");
+    cmd.arg("metadata").arg("--no-deps");
+    if let Some(mani) = manifest_path_arg {
+        cmd.arg(mani);
+    }
+    let output = cmd.output()?;
+    let stdout = from_utf8(&output.stdout)?;
+    let meta: Metadata = serde_json::from_str(&stdout)?;
+    assert_eq!(meta.version, 1, "please update your `cargo_metadata` dependency to support the new metadata version");
+    Ok(meta)
+}