Allow piping from stdin into a buffer on startup (#996)

* Allow piping from stdin into a buffer on startup

* Refactor

* Don't allow piping into new buffer on macOS

* Update helix-term/src/application.rs

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

* Update helix-term/src/application.rs

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

* Fix

Co-authored-by: Blaž Hrastnik <blaz@mxxn.io>

helix-term/src/application.rs

@@ -7,7 +7,7 @@ use crate::{args::Args, compositor::Compositor, config::Config, job::Jobs, ui};
 use log::{error, warn};
 
 use std::{
-    io::{stdout, Write},
+    io::{stdin, stdout, Write},
     sync::Arc,
     time::{Duration, Instant},
 };
@@ -17,6 +17,7 @@ use anyhow::Error;
 use crossterm::{
     event::{DisableMouseCapture, EnableMouseCapture, Event, EventStream},
     execute, terminal,
+    tty::IsTty,
 };
 #[cfg(not(windows))]
 use {
@@ -134,8 +135,17 @@ impl Application {
                 }
                 editor.set_status(format!("Loaded {} files.", nr_of_files));
             }
-        } else {
+        } else if stdin().is_tty() {
             editor.new_file(Action::VerticalSplit);
+        } else if cfg!(target_os = "macos") {
+            // On Linux and Windows, we allow the output of a command to be piped into the new buffer.
+            // This doesn't currently work on macOS because of the following issue:
+            //   https://github.com/crossterm-rs/crossterm/issues/500
+            anyhow::bail!("Piping into helix-term is currently not supported on macOS");
+        } else {
+            editor
+                .new_file_from_stdin(Action::VerticalSplit)
+                .unwrap_or_else(|_| editor.new_file(Action::VerticalSplit));
         }
 
         editor.set_theme(theme);

helix-view/src/editor.rs

@@ -9,6 +9,7 @@ use crate::{
 use futures_util::future;
 use std::{
     collections::BTreeMap,
+    io::stdin,
     path::{Path, PathBuf},
     pin::Pin,
     sync::Arc,
@@ -314,16 +315,24 @@ impl Editor {
         self._refresh();
     }
 
-    pub fn new_file(&mut self, action: Action) -> DocumentId {
+    fn new_file_from_document(&mut self, action: Action, mut document: Document) -> DocumentId {
         let id = DocumentId(self.next_document_id);
         self.next_document_id += 1;
-        let mut doc = Document::default();
-        doc.id = id;
-        self.documents.insert(id, doc);
+        document.id = id;
+        self.documents.insert(id, document);
         self.switch(id, action);
         id
     }
 
+    pub fn new_file(&mut self, action: Action) -> DocumentId {
+        self.new_file_from_document(action, Document::default())
+    }
+
+    pub fn new_file_from_stdin(&mut self, action: Action) -> Result<DocumentId, Error> {
+        let (rope, encoding) = crate::document::from_reader(&mut stdin(), None)?;
+        Ok(self.new_file_from_document(action, Document::from(rope, Some(encoding))))
+    }
+
     pub fn open(&mut self, path: PathBuf, action: Action) -> Result<DocumentId, Error> {
         let path = helix_core::path::get_canonicalized_path(&path)?;