Create a util.py Python module for common functions

Extracting these functions helps avoid circular dependencies,
and make them easier to find/reuse.

python/servo/bootstrap_commands.py

@@ -8,7 +8,6 @@
 # except according to those terms.
 
 from __future__ import print_function, unicode_literals
-from socket import error as socket_error
 
 import base64
 import json
@@ -17,9 +16,6 @@ import os.path as path
 import re
 import shutil
 import sys
-import StringIO
-import tarfile
-import zipfile
 import urllib2
 
 from mach.decorators import (
@@ -28,93 +24,8 @@ from mach.decorators import (
     Command,
 )
 
-from servo.command_base import CommandBase, host_triple, BIN_SUFFIX
-
-
-def download(desc, src, writer, start_byte=0):
-    if start_byte:
-        print("Resuming download of %s..." % desc)
-    else:
-        print("Downloading %s..." % desc)
-    dumb = (os.environ.get("TERM") == "dumb") or (not sys.stdout.isatty())
-
-    try:
-        req = urllib2.Request(src)
-        if start_byte:
-            req = urllib2.Request(src, headers={'Range': 'bytes={}-'.format(start_byte)})
-        resp = urllib2.urlopen(req)
-
-        fsize = None
-        if resp.info().getheader('Content-Length'):
-            fsize = int(resp.info().getheader('Content-Length').strip()) + start_byte
-
-        recved = start_byte
-        chunk_size = 8192
-
-        while True:
-            chunk = resp.read(chunk_size)
-            if not chunk:
-                break
-            recved += len(chunk)
-            if not dumb:
-                if fsize is not None:
-                    pct = recved * 100.0 / fsize
-                    print("\rDownloading %s: %5.1f%%" % (desc, pct), end="")
-
-                sys.stdout.flush()
-            writer.write(chunk)
-
-        if not dumb:
-            print()
-    except urllib2.HTTPError, e:
-        print("Download failed (%d): %s - %s" % (e.code, e.reason, src))
-        if e.code == 403:
-            print("No Rust compiler binary available for this platform. "
-                  "Please see https://github.com/servo/servo/#prerequisites")
-        sys.exit(1)
-    except urllib2.URLError, e:
-        print("Error downloading Rust compiler: %s. The failing URL was: %s" % (e.reason, src))
-        sys.exit(1)
-    except socket_error, e:
-        print("Looks like there's a connectivity issue, check your Internet connection. %s" % (e))
-        sys.exit(1)
-    except KeyboardInterrupt:
-        writer.flush()
-        raise
-
-
-def download_file(desc, src, dst):
-    tmp_path = dst + ".part"
-    try:
-        start_byte = os.path.getsize(tmp_path)
-        with open(tmp_path, 'ab') as fd:
-            download(desc, src, fd, start_byte=start_byte)
-    except os.error:
-        with open(tmp_path, 'wb') as fd:
-            download(desc, src, fd)
-    os.rename(tmp_path, dst)
-
-
-def download_bytes(desc, src):
-    content_writer = StringIO.StringIO()
-    download(desc, src, content_writer)
-    return content_writer.getvalue()
-
-
-def extract(src, dst, movedir=None):
-    if src.endswith(".zip"):
-        zipfile.ZipFile(src).extractall(dst)
-    else:
-        tarfile.open(src).extractall(dst)
-
-    if movedir:
-        for f in os.listdir(movedir):
-            frm = path.join(movedir, f)
-            to = path.join(dst, f)
-            os.rename(frm, to)
-        os.rmdir(movedir)
-
-    os.remove(src)
+from servo.command_base import CommandBase, BIN_SUFFIX
+from servo.util import download_bytes, download_file, extract, host_triple
 
 
 @CommandProvider