added basic version of VCS supprt for configuring files based on VCS state during build time

authors.txt

@@ -9,3 +9,4 @@ Peter Koval
 Masashi Fujita
 Juhani Simola
 Robin McCorkell
+Axel Waggershauser

interpreter.py

@@ -726,6 +726,8 @@ class Interpreter():
                       'get_option' : self.func_get_option,
                       'subproject' : self.func_subproject,
                       'pkgconfig_gen' : self.func_pkgconfig_gen,
+                      'vcs_info' : self.func_vcs_info,
+                      'vcs_configure' : self.func_vcs_configure,
                       }
 
     def get_build_def_files(self):
@@ -829,6 +831,13 @@ class Interpreter():
                 if not isinstance(actual, wanted):
                     raise InvalidArguments('Incorrect argument type.')
 
+    def validate_target_name(self, name):
+        if name in coredata.forbidden_target_names:
+            raise InvalidArguments('Target name "%s" is reserved for Meson\'s internal use. Please rename.'\
+                                   % name)
+        if name in self.build.targets:
+            raise InvalidCode('Tried to create target "%s", but a target of that name already exists.' % name)
+
     def func_run_command(self, node, args, kwargs):
         if len(args) < 1:
             raise InterpreterException('Not enough arguments')
@@ -1119,6 +1128,57 @@ class Interpreter():
         self.build.targets[name] = tg.held_object
         return tg
 
+    def func_vcs_info(self, nodes, args, kwargs):
+        # required: none; optional: name, vcs_cmd, vcs_dir, output, build_always
+        name = args[0] if len(args) > 0 else 'vcs_info'
+        self.validate_target_name(name)
+        vcs_dir = kwargs.pop('vcs_dir', self.environment.get_source_dir())
+        vcs_cmd = None
+
+        vcs_systems = [
+            dict(name = 'git',       cmd = 'git', get_rev = 'git describe', dep = '.git/logs/HEAD', get_root = 'git rev-parse --show-toplevel'),
+            dict(name = 'mercurial', cmd = 'hg',  get_rev = 'hg id -n',     dep = '.hg/dirstate',   get_root = 'hg root'),
+#            dict(name = 'subversion', cmd = 'svn',  get_rev = 'svn info',     dep = '.svn/wc.db',   get_root = 'svn info'),
+        ]
+        for vcs in vcs_systems:
+            if vcs['cmd'] and shutil.which(vcs['cmd']):
+                vcs_root = subprocess.Popen(vcs['get_root'], shell=True, cwd=vcs_dir, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL).communicate()[0].decode().strip()
+                vcs_dep = os.path.join(vcs_root, vcs['dep'])
+                if os.path.exists(vcs_dep):
+                    vcs_cmd = vcs['get_rev']
+                    kwargs['input'] = vcs_dep
+                    mlog.log('Found %s repository at %s' % (vcs['name'], vcs_root))
+                    break
+
+        vcs_cmd = kwargs.pop('vcs_cmd', vcs_cmd )
+        if not vcs_cmd:
+            raise InvalidArguments('Could not autodetect vcs system and no custom vcs_cmd was specified.')
+        kwargs.setdefault('output', name)
+        script = os.path.join(self.environment.get_script_dir(), 'meson_vcs_info.py')
+        kwargs['command'] = [script, 'update', vcs_cmd, vcs_dir, '@OUTPUT0@']
+        tg = CustomTargetHolder(name, self.subdir, kwargs)
+        self.build.targets[name] = tg.held_object
+        return tg
+
+    def func_vcs_configure(self, nodes, args, kwargs):
+        # required: name, input, vcs_info; optional: output, config_var_name
+        name = args[0]
+        self.validate_target_name(name)
+        kwargs.setdefault('input', args[1] if len(args)>1 else None)
+        vcs_info = kwargs.pop('vcs_info', None)
+        if not vcs_info:
+            raise InvalidArguments('Missing argument "vcs_info".')
+        if not isinstance(vcs_info, CustomTargetHolder):
+            raise InterpreterException('Argument "vcs_info" is not of type vcs_info')
+        vcs_info = vcs_info.held_object
+        config_var_name = kwargs.pop('config_var_name', 'VCS_INFO')
+        kwargs.setdefault('output', name)
+        script = os.path.join(self.environment.get_script_dir(), 'meson_vcs_info.py')
+        kwargs['command'] = [script, 'configure', vcs_info, config_var_name, '@INPUT0@', '@OUTPUT0@']
+        tg = CustomTargetHolder(name, self.subdir, kwargs)
+        self.build.targets[name] = tg.held_object
+        return tg
+
     def func_run_target(self, node, args, kwargs):
         if len(args) < 2:
             raise InterpreterException('Incorrect number of arguments')

meson_vcs_info.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+
+# Copyright 2013-2015 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys, os, shutil, shlex, subprocess
+import backends
+
+def update_vcs_info(vcs_cmd, vcs_dir, vcs_info_file):
+    """Update the string in the vcs_info_file with the stdout of vcs_cmd executed in vcs_dir."""
+
+    cmd = shlex.split(vcs_cmd)
+    # Is the command an executable in path or maybe a script in the source tree?
+    cmd[0] = shutil.which(cmd[0]) or os.path.join(vcs_dir, cmd[0])
+
+    try:
+        info = subprocess.check_output(cmd, cwd=vcs_dir)
+    except FileNotFoundError:
+        print('Could not execute command "%s".' % ' '.join(cmd))
+        sys.exit(1)
+    except subprocess.CalledProcessError as e:
+        print('Failed to get repository information from %s.\n' % vcs_dir)
+        sys.exit(e.returncode)
+
+    info = info.strip()
+
+    if (not os.path.exists(vcs_info_file)) or (open(vcs_info_file, 'rb').read() != info):
+        open(vcs_info_file, 'wb').write(info)
+
+
+def configure_vcs_info(vcs_info_file, config_var_name, input_file, output_file):
+    """Configure the input_file by replacing the variable config_var_name with the contents of the vcs_info_file and save it as output_file."""
+
+    info = open(vcs_info_file).read()
+    backends.do_conf_file(input_file, output_file, {config_var_name : info})
+
+
+if __name__ == '__main__':
+    if not len(sys.argv) in [5,6]:
+        print('Version Control Systems helper script for Meson. Do not run on your own, mmm\'kay?')
+        print('%s update <vcs_cmd> <vcs_dir> <vcs_info_file>' % sys.argv[0])
+        print('%s configure <vcs_info_file> <config_var_name> <input_file> <output_file>' % sys.argv[0])
+        sys.exit(1)
+
+    if sys.argv[1] == 'update':
+        update_vcs_info( *sys.argv[2:5] )
+    elif sys.argv[1] == 'configure':
+        configure_vcs_info( *sys.argv[2:6] )
+