Formatting for output of locate-project

src/bin/cargo/commands/locate_project.rs

@@ -1,11 +1,20 @@
 use crate::command_prelude::*;
+use anyhow::{bail, Context, Result};
+use cargo::drop_println;
+use cargo::util::format::{Parser, RawChunk};
 use serde::Serialize;
+use std::fmt;
 
 pub fn cli() -> App {
     subcommand("locate-project")
         .about("Print a JSON representation of a Cargo.toml file's location")
         .arg(opt("quiet", "No output printed to stdout").short("q"))
         .arg_manifest_path()
+        .arg(
+            opt("format", "Format string used for printing project path")
+                .value_name("FORMAT")
+                .short("f"),
+        )
         .after_help("Run `cargo help locate-project` for more detailed information.\n")
 }
 
@@ -29,6 +38,54 @@ pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
 
     let location = ProjectLocation { root };
 
-    config.shell().print_json(&location);
+    match args.value_of("format") {
+        None => config.shell().print_json(&location),
+        Some(format) => print_format(config, &location, format)?,
+    }
+
+    Ok(())
+}
+
+enum Chunk<'a> {
+    Raw(&'a str),
+    Root,
+}
+
+fn parse_format(format: &str) -> Result<Vec<Chunk<'_>>> {
+    let mut chunks = Vec::new();
+    for raw in Parser::new(format) {
+        chunks.push(match raw {
+            RawChunk::Text(text) => Chunk::Raw(text),
+            RawChunk::Argument("root") => Chunk::Root,
+            RawChunk::Argument(a) => bail!("unsupported pattern `{}`", a),
+            RawChunk::Error(err) => bail!("{}", err),
+        });
+    }
+    Ok(chunks)
+}
+
+struct Display<'a> {
+    format: &'a [Chunk<'a>],
+    location: &'a ProjectLocation<'a>,
+}
+
+impl fmt::Display for Display<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for chunk in self.format {
+            match chunk {
+                Chunk::Raw(s) => f.write_str(s)?,
+                Chunk::Root => f.write_str(self.location.root)?,
+            }
+        }
+        Ok(())
+    }
+}
+
+fn print_format(config: &mut Config, location: &ProjectLocation<'_>, format: &str) -> Result<()> {
+    let ref format = parse_format(format)
+        .with_context(|| format!("locate-project format `{}` not valid", format))?;
+
+    let display = Display { format, location };
+    drop_println!(config, "{}", display);
     Ok(())
 }

src/cargo/ops/tree/format/mod.rs → src/cargo/ops/tree/format.rs

@@ -1,10 +1,8 @@
-use self::parse::{Parser, RawChunk};
 use super::{Graph, Node};
+use crate::util::format::{Parser, RawChunk};
 use anyhow::{bail, Error};
 use std::fmt;
 
-mod parse;
-
 enum Chunk {
     Raw(String),
     Package,

src/cargo/util/mod.rs

@@ -39,6 +39,7 @@ mod dependency_queue;
 pub mod diagnostic_server;
 pub mod errors;
 mod flock;
+pub mod format;
 pub mod graph;
 mod hasher;
 pub mod hex;

src/doc/man/cargo-locate-project.md

@@ -18,6 +18,26 @@ workspace root.
 
 ## OPTIONS
 
+### Formatting Options
+
+{{#options}}
+
+{{#option "`-f` _format_" "`--format` _format_" }}
+Set the format string for the output representation. The default is a JSON
+object holding all of the supported information.
+
+This is an arbitrary string which will be used to display the project location.
+The following strings will be replaced with the corresponding value:
+
+- `{root}` — The absolute path of the `Cargo.toml` manifest.
+
+For example you might use `--format '{root}'` or more concisely `-f{root}` to
+output just the path and nothing else, or `--format 'root={root}'` to include a
+prefix.
+{{/option}}
+
+{{/options}}
+
 ### Display Options
 
 {{#options}}

src/doc/man/generated_txt/cargo-locate-project.txt

@@ -15,6 +15,21 @@ DESCRIPTION
        workspace root.
 
 OPTIONS
+   Formatting Options
+       -f format, --format format
+           Set the format string for the output representation. The default is
+           a JSON object holding all of the supported information.
+
+           This is an arbitrary string which will be used to display the
+           project location. The following strings will be replaced with the
+           corresponding value:
+
+           o  {root} — The absolute path of the Cargo.toml manifest.
+
+           For example you might use --format '{root}' or more concisely
+           -f{root} to output just the path and nothing else, or --format
+           'root={root}' to include a prefix.
+
    Display Options
        -v, --verbose
            Use verbose output. May be specified twice for "very verbose" output

src/doc/src/commands/cargo-locate-project.md

@@ -18,6 +18,26 @@ workspace root.
 
 ## OPTIONS
 
+### Formatting Options
+
+<dl>
+
+<dt class="option-term" id="option-cargo-locate-project--f"><a class="option-anchor" href="#option-cargo-locate-project--f"></a><code>-f</code> <em>format</em></dt>
+<dt class="option-term" id="option-cargo-locate-project---format"><a class="option-anchor" href="#option-cargo-locate-project---format"></a><code>--format</code> <em>format</em></dt>
+<dd class="option-desc">Set the format string for the output representation. The default is a JSON
+object holding all of the supported information.</p>
+<p>This is an arbitrary string which will be used to display the project location.
+The following strings will be replaced with the corresponding value:</p>
+<ul>
+<li><code>{root}</code> — The absolute path of the <code>Cargo.toml</code> manifest.</li>
+</ul>
+<p>For example you might use <code>--format '{root}'</code> or more concisely <code>-f{root}</code> to
+output just the path and nothing else, or <code>--format 'root={root}'</code> to include a
+prefix.</dd>
+
+
+</dl>
+
 ### Display Options
 
 <dl>

src/etc/_cargo

@@ -160,7 +160,8 @@ _cargo() {
                         ;;
 
                 locate-project)
-                    _arguments -s -S $common $manifest
+                    _arguments -s -S $common $manifest \
+                        '(-f --format)'{-f,--format=}'[format string]:format'
                         ;;
 
                 login)

src/etc/cargo.bashcomp.sh

@@ -59,7 +59,7 @@ _cargo()
 	local opt__help="$opt_help"
 	local opt__init="$opt_common $opt_lock --bin --lib --name --vcs --edition --registry"
 	local opt__install="$opt_common $opt_feat $opt_jobs $opt_lock $opt_force --bin --bins --branch --debug --example --examples --git --list --path --rev --root --tag --version --registry --target --profile --no-track"
-	local opt__locate_project="$opt_common $opt_mani $opt_lock"
+	local opt__locate_project="$opt_common $opt_mani $opt_lock -f --format"
 	local opt__login="$opt_common $opt_lock --registry"
 	local opt__metadata="$opt_common $opt_feat $opt_mani $opt_lock --format-version=1 --no-deps --filter-platform"
 	local opt__new="$opt_common $opt_lock --vcs --bin --lib --name --edition --registry"

src/etc/man/cargo-locate-project.1

@@ -14,6 +14,25 @@ This command will print a JSON object to stdout with the full path to the
 See also \fBcargo\-metadata\fR(1) which is capable of returning the path to a
 workspace root.
 .SH "OPTIONS"
+.SS "Formatting Options"
+.sp
+\fB\-f\fR \fIformat\fR, 
+\fB\-\-format\fR \fIformat\fR
+.RS 4
+Set the format string for the output representation. The default is a JSON
+object holding all of the supported information.
+.sp
+This is an arbitrary string which will be used to display the project location.
+The following strings will be replaced with the corresponding value:
+.sp
+.RS 4
+\h'-04'\(bu\h'+02'\fB{root}\fR \[em] The absolute path of the \fBCargo.toml\fR manifest.
+.RE
+.sp
+For example you might use \fB\-\-format '{root}'\fR or more concisely \fB\-f{root}\fR to
+output just the path and nothing else, or \fB\-\-format 'root={root}'\fR to include a
+prefix.
+.RE
 .SS "Display Options"
 .sp
 \fB\-v\fR, 

tests/testsuite/locate_project.rs

@@ -14,3 +14,34 @@ fn simple() {
         ))
         .run();
 }
+
+#[cargo_test]
+fn format() {
+    let p = project().build();
+    let root_manifest_path = p.root().join("Cargo.toml");
+    let root_str = root_manifest_path.to_str().unwrap();
+
+    p.cargo("locate-project --format {root}")
+        .with_stdout(root_str)
+        .run();
+
+    p.cargo("locate-project -f{root}")
+        .with_stdout(root_str)
+        .run();
+
+    p.cargo("locate-project --format root={root}")
+        .with_stdout(format!("root={}", root_str))
+        .run();
+
+    p.cargo("locate-project --format {toor}")
+        .with_stderr(
+            "\
+[ERROR] locate-project format `{toor}` not valid
+
+Caused by:
+  unsupported pattern `toor`
+",
+        )
+        .with_status(101)
+        .run();
+}