JRuby

Get the terminal width with JRuby

Details

  • Type: Bug Bug
  • Status: Resolved Resolved
  • Priority: Major Major
  • Resolution: Fixed
  • Affects Version/s: None
  • Fix Version/s: JRuby 1.7.0.pre2
  • Component/s: None
  • Labels:
    None
  • Number of attachments :
    0

Description

Noticing that Rake always truncate my output for `rake -T` at 80 chars (which is quite annoying), I wondered what was not working.

Rake uses `stty size` and `tput cols` to guess the terminal width.
The first gives "stty: stdin isn't a terminal" and the second returns 80, which is not my terminal width (176).

So, what is the recommended way to obtain the terminal width in JRuby?

(Adding export RAKE_COLUMNS=$COLUMNS in my .zshrc works but that's just a workaround for rake)

Activity

Ascending order - Click to sort in descending order
Hide
Permalink
Charles Oliver Nutter added a comment -

This is another stty case where we need to do subprocess launching separate from Java's normal launching, so it can inherit tty.

I may see if I can't build out a few of the key subprocess launching APIs to use the newer Java 7 process launching that allows inheriting.

Show
Charles Oliver Nutter added a comment - This is another stty case where we need to do subprocess launching separate from Java's normal launching, so it can inherit tty. I may see if I can't build out a few of the key subprocess launching APIs to use the newer Java 7 process launching that allows inheriting.
Hide
Permalink
Charles Oliver Nutter added a comment -

Here's a monkey-patch for Kernel#` that makes it use Java 7 subprocess API with tty inheriting:

system ~/projects/jruby $ jruby -rjruby/kernel/jruby/process_manager -e 'puts `stty`'
speed 9600 baud;
lflags: echoe echoke echoctl pendin
oflags: -oxtabs
cflags: cs8 -parenb

system ~/projects/jruby $ jruby -rjruby/kernel/jruby/process_manager -e 'puts `stty size`'
55 183

system ~/projects/jruby $ jruby -rjruby/kernel/jruby/process_manager -e 'puts `tput cols`'
80

system ~/projects/jruby $ git diff
diff --git a/src/jruby/kernel/jruby/process_manager.rb b/src/jruby/kernel/jruby/process_manager.rb
index e69de29..47da5c7 100644
--- a/src/jruby/kernel/jruby/process_manager.rb
+++ b/src/jruby/kernel/jruby/process_manager.rb
@@ -0,0 +1,27 @@
+require 'java'
+require 'jruby'
+
+module JRuby
+  module ProcessManager
+    java_import java.lang.ProcessBuilder
+    Redirect = ProcessBuilder::Redirect
+
+    def self.`(command)
+      pb = ProcessBuilder.new(command.split(/\W/).to_java(:string))
+      pb.redirect_input(Redirect::INHERIT)
+      process = pb.start
+
+      out = process.input_stream
+      result = out.to_io.read
+
+      result
+    end
+  end
+end
+
+module Kernel
+  module_function
+  def `(command)
+    JRuby::ProcessManager.`(command)
+  end
+end
\ No newline at end of file

Note that `stty size` works, but `tput cols` still shows 80. Not sure what else we need to do to make that match MRI.

I am looking into the feasibility of getting this into pre2 as a Java 7-specific impl of ` (and other process-launching stuff).

Show
Charles Oliver Nutter added a comment - Here's a monkey-patch for Kernel#` that makes it use Java 7 subprocess API with tty inheriting: system ~/projects/jruby $ jruby -rjruby/kernel/jruby/process_manager -e 'puts `stty`' speed 9600 baud; lflags: echoe echoke echoctl pendin oflags: -oxtabs cflags: cs8 -parenb system ~/projects/jruby $ jruby -rjruby/kernel/jruby/process_manager -e 'puts `stty size`' 55 183 system ~/projects/jruby $ jruby -rjruby/kernel/jruby/process_manager -e 'puts `tput cols`' 80 system ~/projects/jruby $ git diff diff --git a/src/jruby/kernel/jruby/process_manager.rb b/src/jruby/kernel/jruby/process_manager.rb index e69de29..47da5c7 100644 --- a/src/jruby/kernel/jruby/process_manager.rb +++ b/src/jruby/kernel/jruby/process_manager.rb @@ -0,0 +1,27 @@ +require 'java' +require 'jruby' + +module JRuby + module ProcessManager + java_import java.lang.ProcessBuilder + Redirect = ProcessBuilder::Redirect + + def self.`(command) + pb = ProcessBuilder.new(command.split(/\W/).to_java(:string)) + pb.redirect_input(Redirect::INHERIT) + process = pb.start + + out = process.input_stream + result = out.to_io.read + + result + end + end +end + +module Kernel + module_function + def `(command) + JRuby::ProcessManager.`(command) + end +end \ No newline at end of file Note that `stty size` works, but `tput cols` still shows 80. Not sure what else we need to do to make that match MRI. I am looking into the feasibility of getting this into pre2 as a Java 7-specific impl of ` (and other process-launching stuff).
Hide
Permalink
Benoit Daloze added a comment -

Sounds great! I will try that tomorrow.

Show
Benoit Daloze added a comment - Sounds great! I will try that tomorrow.
Hide
Permalink
Benoit Daloze added a comment -

Worked at me after a full rebuild.
The issue with tput is weird. I guess it takes the information in a different way.

Could this be included by default for when running with Java 7 for standard process spawning ?
Any step towards better terminal handling is definitely good.

Show
Benoit Daloze added a comment - Worked at me after a full rebuild. The issue with tput is weird. I guess it takes the information in a different way. Could this be included by default for when running with Java 7 for standard process spawning ? Any step towards better terminal handling is definitely good.
Hide
Permalink
Charles Oliver Nutter added a comment -

I am working on a patch to add it by default, along with setting up the framework for implementing more process methods this way.

Show
Charles Oliver Nutter added a comment - I am working on a patch to add it by default, along with setting up the framework for implementing more process methods this way.
Hide
Permalink
Charles Oliver Nutter added a comment - - edited

This fix only resolves the issues on Java 7. For Java 6 and earlier we'd need to implement native process launching using jnr-posix.

commit c7c7c7d12f43f56e5e004f8535e42118c04969f0
Author: Charles Oliver Nutter <headius@headius.com>
Date:   Wed Jun 13 19:38:13 2012 -0500

    Add reimpl of Kernel#` using Java 7 process APIs.
Show
Charles Oliver Nutter added a comment - - edited This fix only resolves the issues on Java 7. For Java 6 and earlier we'd need to implement native process launching using jnr-posix. commit c7c7c7d12f43f56e5e004f8535e42118c04969f0 Author: Charles Oliver Nutter <headius@headius.com> Date: Wed Jun 13 19:38:13 2012 -0500 Add reimpl of Kernel#` using Java 7 process APIs.

People

  • Assignee:
    Charles Oliver Nutter
    Reporter:
    Benoit Daloze
Vote (0)
Watch (3)

Dates

  • Created:
    Updated:
    Resolved: