Add cargo doc --lib/--bin

Allows documenting a specific target.

Closes #2557

src/bin/doc.rs

@@ -16,6 +16,8 @@ pub struct Options {
     flag_quiet: Option<bool>,
     flag_color: Option<String>,
     flag_package: Vec<String>,
+    flag_lib: bool,
+    flag_bin: Vec<String>,
 }
 
 pub const USAGE: &'static str = "
@@ -30,6 +32,8 @@ Options:
     -p SPEC, --package SPEC ...  Package to document
     --no-deps                    Don't build documentation for dependencies
     -j N, --jobs N               The number of jobs to run in parallel
+    --lib                        Document only this package's library
+    --bin NAME                   Document only the specified binary
     --release                    Build artifacts in release mode, with optimizations
     --features FEATURES          Space-separated list of features to also build
     --no-default-features        Do not build the `default` feature
@@ -55,6 +59,7 @@ pub fn execute(options: Options, config: &Config) -> CliResult<Option<()>> {
 
     let root = try!(find_root_manifest_for_wd(options.flag_manifest_path, config.cwd()));
 
+    let empty = Vec::new();
     let doc_opts = ops::DocOptions {
         open_result: options.flag_open,
         compile_opts: ops::CompileOptions {
@@ -65,7 +70,11 @@ pub fn execute(options: Options, config: &Config) -> CliResult<Option<()>> {
             no_default_features: options.flag_no_default_features,
             spec: &options.flag_package,
             exec_engine: None,
-            filter: ops::CompileFilter::Everything,
+            filter: ops::CompileFilter::new(options.flag_lib,
+                                            &options.flag_bin,
+                                            &empty,
+                                            &empty,
+                                            &empty),
             release: options.flag_release,
             mode: ops::CompileMode::Doc {
                 deps: !options.flag_no_deps,

tests/test_cargo_doc.rs

@@ -550,3 +550,27 @@ test!(rerun_when_dir_removed {
                 execs().with_status(0));
     assert_that(&p.root().join("target/doc/foo/index.html"), existing_file());
 });
+
+test!(document_only_lib {
+    let p = project("foo")
+        .file("Cargo.toml", r#"
+            [package]
+            name = "foo"
+            version = "0.0.1"
+            authors = []
+        "#)
+        .file("src/lib.rs", r#"
+            /// dox
+            pub fn foo() {}
+        "#)
+        .file("src/bin/bar.rs", r#"
+            /// ```
+            /// ☃
+            /// ```
+            pub fn foo() {}
+            fn main() { foo(); }
+        "#);
+    assert_that(p.cargo_process("doc").arg("--lib"),
+                execs().with_status(0));
+    assert_that(&p.root().join("target/doc/foo/index.html"), existing_file());
+});