Move the code from appveyor config to a Python script

No more PowerShell rubbish, yay!

support/build.py

@@ -1,14 +1,30 @@
 #!/usr/bin/env python
 # Build the project on AppVeyor.
 
-from subprocess import check_call
 import os
+from download import Downloader
+from subprocess import check_call
 
-env = os.environ
-build = env['BUILD']
-cmake_command = ['cmake', '-DFMT_EXTRA_TESTS=ON', '-DCMAKE_BUILD_TYPE=' + env['CONFIG']]
+build = os.environ['BUILD']
+cmake_command = ['cmake', '-DFMT_EXTRA_TESTS=ON', '-DCMAKE_BUILD_TYPE=' + os.environ['CONFIG']]
+build_command = ['msbuild', '/m:4', '/p:Config=' + os.environ['CONFIG'], 'FORMAT.sln']
+test_command = ['msbuild', 'RUN_TESTS.vcxproj']
 if build == 'mingw':
+  # Install MinGW.
+  mingw_url = 'http://sourceforge.net/projects/mingw-w64/files/' + \
+    'Toolchains%20targetting%20Win64/Personal%20Builds/' + \
+    'mingw-builds/4.9.2/threads-win32/seh/' + \
+    'x86_64-4.9.2-release-win32-seh-rt_v3-rev1.7z/download'
+  with Downloader().download(mingw_url) as f:
+    check_call(['7z', 'x', '-oC:\\', f])
+    
   # Remove path to Git bin directory from $PATH because it breaks MinGW config.
-  env['PATH'] = env['PATH'].replace(r'C:\Program Files (x86)\Git\bin', '')
+  path = os.environ['PATH'].replace(r'C:\Program Files (x86)\Git\bin', '')
+
+  os.environ['PATH'] = r'C:\Program Files (x86)\MSBUILD\12.0\bin\;' + path + r';C:\mingw64\bin'
   cmake_command.append('-GMinGW Makefiles')
-check_call(cmake_command, env=env)
+  build_command = ['mingw32-make', '-j4']
+  test_command = ['mingw32-make', 'test']
+
+check_call(cmake_command)
+check_call(build_command)

support/download.py

@@ -0,0 +1,46 @@
+# A file downloader.
+
+import contextlib, os, tempfile, timer, urllib2, urlparse
+
+class Downloader:
+  def __init__(self, dir=None):
+    self.dir = dir
+
+  # Downloads a file and removes it when exiting a block.
+  # Usage:
+  #  d = Downloader()
+  #  with d.download(url) as f:
+  #    use_file(f)
+  def download(self, url, cookie=None):
+    suffix = os.path.splitext(urlparse.urlsplit(url)[2])[1]
+    fd, filename = tempfile.mkstemp(suffix=suffix, dir=self.dir)
+    os.close(fd)
+    with timer.print_time('Downloading', url, 'to', filename):
+      opener = urllib2.build_opener()
+      if cookie:
+        opener.addheaders.append(('Cookie', cookie))
+      num_tries = 2
+      for i in range(num_tries):
+        try:
+          f = opener.open(url)
+        except urllib2.URLError, e:
+          print('Failed to open url', url)
+          continue
+        length = f.headers.get('content-length')
+        if not length:
+          print('Failed to get content-length')
+          continue
+        length = int(length)
+        with open(filename, 'wb') as out:
+          count = 0
+          while count < length:
+            data = f.read(1024 * 1024)
+            count += len(data)
+            out.write(data)
+    @contextlib.contextmanager
+    def remove(filename):
+      try:
+        yield filename
+      finally:
+        pass #os.remove(filename)
+    return remove(filename)

support/timer.py

@@ -0,0 +1,35 @@
+# A with statement based timer.
+
+from __future__ import print_function
+from contextlib import contextmanager
+import timeit
+
+class Timer:
+  """
+  A with statement based timer.
+  Usage:
+    t = Timer()
+    with t:
+      do_something()
+    time = t.time
+  """
+    
+  def __enter__(self):
+    self.start = timeit.default_timer()
+
+  def __exit__(self, type, value, traceback):
+    finish = timeit.default_timer()
+    self.time = finish - self.start
+
+@contextmanager
+def print_time(*args):
+  """
+  Measures and prints the time taken to execute nested code.
+  args: Additional arguments to print.
+  """
+  t = Timer()
+  print(*args)
+  with t:
+    yield
+  print(*args, end=' ')
+  print('finished in {0:.2f} second(s)'.format(t.time))