packaging: split Inno installer building from Mercurial building

We want to make the logic for producing the installer agnostic about
how Mercurial is built to allow for alternate build methods (like
PyOxidizer).

Differential Revision: https://phab.mercurial-scm.org/D8472

contrib/packaging/hgpackaging/inno.py

@@ -1,173 +1,197 b''
 # inno.py - Inno Setup functionality.
 #
 # Copyright 2019 Gregory Szorc <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 # no-check-code because Python 3 native.
 
 import os
 import pathlib
 import shutil
 import subprocess
 
 import jinja2
 
 from .py2exe import (
     build_py2exe,
     stage_install,
 )
 from .util import (
     find_vc_runtime_files,
     normalize_windows_version,
     process_install_rules,
     read_version_py,
 )
 
 EXTRA_PACKAGES = {
     'dulwich',
     'keyring',
     'pygments',
     'win32ctypes',
 }
 
 EXTRA_INSTALL_RULES = [
     ('contrib/win32/mercurial.ini', 'defaultrc/mercurial.rc'),
 ]
 
 PACKAGE_FILES_METADATA = {
     'ReadMe.html': 'Flags: isreadme',
 }
 
 
 def build(
     source_dir: pathlib.Path,
     build_dir: pathlib.Path,
     python_exe: pathlib.Path,
     iscc_exe: pathlib.Path,
     version=None,
 ):
     """Build the Inno installer.
 
     Build files will be placed in ``build_dir``.
 
     py2exe's setup.py doesn't use setuptools. It doesn't have modern logic
     for finding the Python 2.7 toolchain. So, we require the environment
     to already be configured with an active toolchain.
     """
     if not iscc_exe.exists():
         raise Exception('%s does not exist' % iscc_exe)
 
     vc_x64 = r'\x64' in os.environ.get('LIB', '')
     arch = 'x64' if vc_x64 else 'x86'
-    inno_source_dir = source_dir / 'contrib' / 'packaging' / 'inno'
-    inno_build_dir = build_dir / ('inno-%s' % arch)
+    inno_build_dir = build_dir / ('inno-py2exe-%s' % arch)
     staging_dir = inno_build_dir / 'stage'
 
     requirements_txt = (
         source_dir / 'contrib' / 'packaging' / 'requirements_win32.txt'
     )
 
     inno_build_dir.mkdir(parents=True, exist_ok=True)
 
     build_py2exe(
         source_dir,
         build_dir,
         python_exe,
         'inno',
         requirements_txt,
         extra_packages=EXTRA_PACKAGES,
     )
 
     # Purge the staging directory for every build so packaging is
     # pristine.
     if staging_dir.exists():
         print('purging %s' % staging_dir)
         shutil.rmtree(staging_dir)
 
     # Now assemble all the packaged files into the staging directory.
     stage_install(source_dir, staging_dir)
 
     # We also install some extra files.
     process_install_rules(EXTRA_INSTALL_RULES, source_dir, staging_dir)
 
     # hg.exe depends on VC9 runtime DLLs. Copy those into place.
     for f in find_vc_runtime_files(vc_x64):
         if f.name.endswith('.manifest'):
             basename = 'Microsoft.VC90.CRT.manifest'
         else:
             basename = f.name
 
         dest_path = staging_dir / basename
 
         print('copying %s to %s' % (f, dest_path))
         shutil.copyfile(f, dest_path)
 
+    build_installer(
+        source_dir,
+        inno_build_dir,
+        staging_dir,
+        iscc_exe,
+        version,
+        arch="x64" if vc_x64 else None,
+    )
+
+
+def build_installer(
+    source_dir: pathlib.Path,
+    inno_build_dir: pathlib.Path,
+    staging_dir: pathlib.Path,
+    iscc_exe: pathlib.Path,
+    version,
+    arch=None,
+):
+    """Build an Inno installer from staged Mercurial files.
+
+    This function is agnostic about how to build Mercurial. It just
+    cares that Mercurial files are in ``staging_dir``.
+    """
+    inno_source_dir = source_dir / "contrib" / "packaging" / "inno"
+
     # The final package layout is simply a mirror of the staging directory.
     package_files = []
     for root, dirs, files in os.walk(staging_dir):
         dirs.sort()
 
         root = pathlib.Path(root)
 
         for f in sorted(files):
             full = root / f
             rel = full.relative_to(staging_dir)
             if str(rel.parent) == '.':
                 dest_dir = '{app}'
             else:
                 dest_dir = '{app}\\%s' % rel.parent
 
             package_files.append(
                 {
                     'source': rel,
                     'dest_dir': dest_dir,
                     'metadata': PACKAGE_FILES_METADATA.get(str(rel), None),
                 }
             )
 
     print('creating installer')
 
     # Install Inno files by rendering a template.
     jinja_env = jinja2.Environment(
         loader=jinja2.FileSystemLoader(str(inno_source_dir)),
         # Need to change these to prevent conflict with Inno Setup.
         comment_start_string='{##',
         comment_end_string='##}',
     )
 
     try:
         template = jinja_env.get_template('mercurial.iss')
     except jinja2.TemplateSyntaxError as e:
         raise Exception(
             'template syntax error at %s:%d: %s'
             % (e.name, e.lineno, e.message,)
         )
 
     content = template.render(package_files=package_files)
 
     with (inno_build_dir / 'mercurial.iss').open('w', encoding='utf-8') as fh:
         fh.write(content)
 
     # Copy additional files used by Inno.
     for p in ('mercurial.ico', 'postinstall.txt'):
         shutil.copyfile(
             source_dir / 'contrib' / 'win32' / p, inno_build_dir / p
         )
 
     args = [str(iscc_exe)]
 
-    if vc_x64:
-        args.append('/dARCH=x64')
+    if arch:
+        args.append('/dARCH=%s' % arch)
 
     if not version:
         version = read_version_py(source_dir)
 
     args.append('/dVERSION=%s' % version)
     args.append('/dQUAD_VERSION=%s' % normalize_windows_version(version))
 
     args.append('/Odist')
     args.append(str(inno_build_dir / 'mercurial.iss'))
 
     subprocess.run(args, cwd=str(source_dir), check=True)