The exec.py plugin from Sublime Text 2.0.2 modified to use incremental decoding

exec.py

import sublime, sublime_plugin
import os, sys, codecs
import thread
import subprocess
import functools
import time

# This is the exec.py file taken from the Default package in Sublime Text 2.0.2
# which has been modified to use incremental decoding of build system output
# the way it's done in Sublime Text 3.
#
# The code is Copyright (c) Sublime HQ Pty Inc and provided here to assist those
# still using Sublime Text 2, which is no longer actively supported.

class ProcessListener(object):
    def on_data(self, proc, data):
        pass

    def on_finished(self, proc):
        pass

# Encapsulates subprocess.Popen, forwarding stdout to a supplied
# ProcessListener (on a separate thread)
class AsyncProcess(object):
    def __init__(self, arg_list, env, listener,
            # "path" is an option in build systems
            path="",
            # "shell" is an options in build systems
            shell=False):

        self.listener = listener
        self.killed = False

        self.start_time = time.time()

        # Hide the console window on Windows
        startupinfo = None
        if os.name == "nt":
            startupinfo = subprocess.STARTUPINFO()
            startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW

        # Set temporary PATH to locate executable in arg_list
        if path:
            old_path = os.environ["PATH"]
            # The user decides in the build system whether he wants to append $PATH
            # or tuck it at the front: "$PATH;C:\\new\\path", "C:\\new\\path;$PATH"
            os.environ["PATH"] = os.path.expandvars(path).encode(sys.getfilesystemencoding())

        proc_env = os.environ.copy()
        proc_env.update(env)
        for k, v in proc_env.iteritems():
            proc_env[k] = os.path.expandvars(v).encode(sys.getfilesystemencoding())

        self.proc = subprocess.Popen(arg_list, stdout=subprocess.PIPE,
            stderr=subprocess.PIPE, startupinfo=startupinfo, env=proc_env, shell=shell)

        if path:
            os.environ["PATH"] = old_path

        if self.proc.stdout:
            thread.start_new_thread(self.read_stdout, ())

        if self.proc.stderr:
            thread.start_new_thread(self.read_stderr, ())

    def kill(self):
        if not self.killed:
            self.killed = True
            self.proc.terminate()
            self.listener = None

    def poll(self):
        return self.proc.poll() == None

    def exit_code(self):
        return self.proc.poll()

    def read_stdout(self):
        decoder_cls = codecs.getincrementaldecoder(self.listener.encoding)
        decoder = decoder_cls('replace')
        while True:
            data = decoder.decode(os.read(self.proc.stdout.fileno(), 2**15))

            if data != "":
                if self.listener:
                    self.listener.on_data(self, data)
            else:
                self.proc.stdout.close()
                if self.listener:
                    self.listener.on_finished(self)
                break

    def read_stderr(self):
        decoder_cls = codecs.getincrementaldecoder(self.listener.encoding)
        decoder = decoder_cls('replace')
        while True:
            data = decoder.decode(os.read(self.proc.stderr.fileno(), 2**15))

            if data != "":
                if self.listener:
                    self.listener.on_data(self, data)
            else:
                self.proc.stderr.close()
                break

class ExecCommand(sublime_plugin.WindowCommand, ProcessListener):
    def run(self, cmd = [], file_regex = "", line_regex = "", working_dir = "",
            encoding = "utf-8", env = {}, quiet = False, kill = False,
            # Catches "path" and "shell"
            **kwargs):

        if kill:
            if self.proc:
                self.proc.kill()
                self.proc = None
                self.append_data(None, "[Cancelled]")
            return

        if not hasattr(self, 'output_view'):
            # Try not to call get_output_panel until the regexes are assigned
            self.output_view = self.window.get_output_panel("exec")

        # Default the to the current files directory if no working directory was given
        if (working_dir == "" and self.window.active_view()
                        and self.window.active_view().file_name()):
            working_dir = os.path.dirname(self.window.active_view().file_name())

        self.output_view.settings().set("result_file_regex", file_regex)
        self.output_view.settings().set("result_line_regex", line_regex)
        self.output_view.settings().set("result_base_dir", working_dir)

        # Call get_output_panel a second time after assigning the above
        # settings, so that it'll be picked up as a result buffer
        self.window.get_output_panel("exec")

        self.encoding = encoding
        self.quiet = quiet

        self.proc = None
        if not self.quiet:
            print "Running " + " ".join(cmd)
            sublime.status_message("Building")

        show_panel_on_build = sublime.load_settings("Preferences.sublime-settings").get("show_panel_on_build", True)
        if show_panel_on_build:
            self.window.run_command("show_panel", {"panel": "output.exec"})

        merged_env = env.copy()
        if self.window.active_view():
            user_env = self.window.active_view().settings().get('build_env')
            if user_env:
                merged_env.update(user_env)

        # Change to the working dir, rather than spawning the process with it,
        # so that emitted working dir relative path names make sense
        if working_dir != "":
            os.chdir(working_dir)

        err_type = OSError
        if os.name == "nt":
            err_type = WindowsError

        try:
            # Forward kwargs to AsyncProcess
            self.proc = AsyncProcess(cmd, merged_env, self, **kwargs)
        except err_type as e:
            self.append_data(None, str(e) + "\n")
            self.append_data(None, "[cmd:  " + str(cmd) + "]\n")
            self.append_data(None, "[dir:  " + str(os.getcwdu()) + "]\n")
            if "PATH" in merged_env:
                self.append_data(None, "[path: " + str(merged_env["PATH"]) + "]\n")
            else:
                self.append_data(None, "[path: " + str(os.environ["PATH"]) + "]\n")
            if not self.quiet:
                self.append_data(None, "[Finished]")

    def is_enabled(self, kill = False):
        if kill:
            return hasattr(self, 'proc') and self.proc and self.proc.poll()
        else:
            return True

    def append_data(self, proc, data):
        if proc != self.proc:
            # a second call to exec has been made before the first one
            # finished, ignore it instead of intermingling the output.
            if proc:
                proc.kill()
            return

        str = data

        # Normalize newlines, Sublime Text always uses a single \n separator
        # in memory.
        str = str.replace('\r\n', '\n').replace('\r', '\n')

        selection_was_at_end = (len(self.output_view.sel()) == 1
            and self.output_view.sel()[0]
                == sublime.Region(self.output_view.size()))
        self.output_view.set_read_only(False)
        edit = self.output_view.begin_edit()
        self.output_view.insert(edit, self.output_view.size(), str)
        if selection_was_at_end:
            self.output_view.show(self.output_view.size())
        self.output_view.end_edit(edit)
        self.output_view.set_read_only(True)

    def finish(self, proc):
        if not self.quiet:
            elapsed = time.time() - proc.start_time
            exit_code = proc.exit_code()
            if exit_code == 0 or exit_code == None:
                self.append_data(proc, ("[Finished in %.1fs]") % (elapsed))
            else:
                self.append_data(proc, ("[Finished in %.1fs with exit code %d]") % (elapsed, exit_code))

        if proc != self.proc:
            return

        errs = self.output_view.find_all_results()
        if len(errs) == 0:
            sublime.status_message("Build finished")
        else:
            sublime.status_message(("Build finished with %d errors") % len(errs))

        # Set the selection to the start, so that next_result will work as expected
        edit = self.output_view.begin_edit()
        self.output_view.sel().clear()
        self.output_view.sel().add(sublime.Region(0))
        self.output_view.end_edit(edit)

    def on_data(self, proc, data):
        sublime.set_timeout(functools.partial(self.append_data, proc, data), 0)

    def on_finished(self, proc):
        sublime.set_timeout(functools.partial(self.finish, proc), 0)

The first revision of the file is the default version that ships with Sublime Text 2.0.2, which decodes the data as it's received by the exec command for display in the command buffer . This seems to cause issues with decoding of multi byte UTF-8 data in certain circumstances, I presume due to potential unfortunate partially delivered data.

The version in the second revision is modified to use an incremental decoder, and decoding is done at the point where the data is read from the pipe instead of at the point where it's being received by the exec command.

This is how Sublime Text 3 performs this task (with a myriad of other enhancements).

This is two revisions on purpose so that you can see the diff to easily see the changes made.

To use this, back up the Default\exec.py file in the Packages folder (use Preferences > Browse Packages... from the menu to find that) and then replace the installed version with the version outlined here. To revert to the original version, put your backup version back in or retrieve the version from the Default.sublime-package in the Pristine Packages folder.