Add hide_success and hide_progress options

doc/comparison.md

@@ -15,6 +15,15 @@ Here are some things n2 improves over Ninja:
 - `-d trace` generates a performance trace that can be visualized by Chrome's
   `about:tracing` or alternatives (speedscope, perfetto).
 
+### Extensions
+
+Some extra build variables are available only in n2:
+
+- `hide_progress`: build edges with this flag will not show the last
+line of output in the fancy progress output.
+- `hide_success`: build edges with this flag will not show the complete
+command output when the command completes successfully.
+
 ## Missing
 
 - Windows is incomplete.

src/graph.rs

@@ -174,6 +174,11 @@ pub struct Build {
 
     /// Output files.
     pub outs: BuildOuts,
+
+    /// True if output of command should be hidden on successful completion.
+    pub hide_success: bool,
+    /// True if last line of output should not be shown in status.
+    pub hide_progress: bool,
 }
 impl Build {
     pub fn new(loc: FileLoc, ins: BuildIns, outs: BuildOuts) -> Self {
@@ -188,6 +193,8 @@ impl Build {
             ins,
             discovered_ins: Vec::new(),
             outs,
+            hide_success: false,
+            hide_progress: false,
         }
     }
 

src/load.rs

@@ -158,13 +158,17 @@ impl Loader {
             }),
             _ => bail!("rspfile and rspfile_content need to be both specified"),
         };
+        let hide_success = lookup("hide_success").is_some();
+        let hide_progress = lookup("hide_progress").is_some();
 
         build.cmdline = cmdline;
         build.desc = desc;
         build.depfile = depfile;
         build.parse_showincludes = parse_showincludes;
         build.rspfile = rspfile;
         build.pool = pool;
+        build.hide_success = hide_success;
+        build.hide_progress = hide_progress;
 
         self.graph.add_build(build)
     }

src/parse.rs

@@ -157,6 +157,8 @@ impl<'text> Parser<'text> {
                     | "rspfile"
                     | "rspfile_content"
                     | "msvc_deps_prefix"
+                    | "hide_success"
+                    | "hide_progress"
             )
         })?;
         Ok(Rule { name, vars })

src/progress_dumb.rs

@@ -46,18 +46,22 @@ impl Progress for DumbConsoleProgress {
     }
 
     fn task_finished(&self, id: BuildId, build: &Build, result: &TaskResult) {
+        let mut hide_output = result.output.is_empty();
         match result.termination {
             Termination::Success => {
                 if result.output.is_empty() || self.last_started.get() == Some(id) {
                     // Output is empty, or we just printed the command, don't print it again.
                 } else {
                     self.log(build_message(build))
                 }
+                if build.hide_success {
+                    hide_output = true;
+                }
             }
             Termination::Interrupted => self.log(&format!("interrupted: {}", build_message(build))),
             Termination::Failure => self.log(&format!("failed: {}", build_message(build))),
         };
-        if !result.output.is_empty() {
+        if !hide_output {
             std::io::stdout().write_all(&result.output).unwrap();
         }
     }

src/progress_fancy.rs

@@ -180,7 +180,7 @@ impl FancyState {
         // Show task name, status, and output.
         let buf = &mut self.pending;
         match result.termination {
-            Termination::Success if result.output.is_empty() => {
+            Termination::Success if result.output.is_empty() || build.hide_success => {
                 // Common case: don't show anything.
                 return;
             }

src/task.rs

@@ -215,6 +215,7 @@ impl Runner {
         let depfile = build.depfile.clone().map(PathBuf::from);
         let rspfile = build.rspfile.clone();
         let parse_showincludes = build.parse_showincludes;
+        let hide_progress = build.hide_progress;
 
         let tid = self.tids.claim();
         let tx = self.tx.clone();
@@ -226,7 +227,9 @@ impl Runner {
                 parse_showincludes,
                 rspfile.as_ref(),
                 |line| {
-                    let _ = tx.send(Message::Output((id, line.to_owned())));
+                    if !hide_progress {
+                        let _ = tx.send(Message::Output((id, line.to_owned())));
+                    }
                 },
             )
             .unwrap_or_else(|err| TaskResult {