waf: git_submodule: add git_submodule tool

Tools/ardupilotwaf/git_submodule.py

@@ -0,0 +1,93 @@
+#!/usr/bin/env python
+# encoding: utf-8
+
+"""
+Waf tool for defining ardupilot's submodules, so that they are kept up to date.
+Submodules can be considered dynamic sources, since they are updated during the
+build. Furthermore, they can be used to generate other dynamic sources (mavlink
+headers generation, for example). Thus, the correct use of this tool should
+have three build groups: first one for updating the submodules, second for
+generating any dynamic source from them, and the last one for the build. And
+post_mode should be set to POST_LAZY. Example::
+
+    def build(bld):
+        bld.post_mode = waflib.Build.POST_LAZY
+
+        bld.add_group('git_submodules')
+        # gtest submodule
+        bld(
+            features='git_submodule'
+            git_submodule='gtest',
+        )
+        # mavlink submodule with syntactic sugar
+        bld.git_submodule('mavlink')
+        ...
+
+        # now, for the dynamic sources
+        bld.add_group('dynamic_sources')
+        ...
+
+        # now, below go the task generators for normal build process
+        bld.add_group('build')
+        ...
+"""
+
+from waflib import Context, Task, Utils
+from waflib.Configure import conf
+from waflib.TaskGen import before_method, feature, taskgen_method
+
+import os.path
+
+class update_submodule(Task.Task):
+    color = 'BLUE'
+    run_str = '${GIT} -C ${SRC_ROOT} submodule update --init -- ${SUBMODULE_PATH}'
+
+    def runnable_status(self):
+        e = self.env.get_flat
+        cmd = e('GIT'), '-C', e('SRC_ROOT'), 'submodule', 'status', '--', e('SUBMODULE_PATH')
+        out = self.generator.bld.cmd_and_log(cmd, quiet=Context.BOTH)
+
+        # git submodule status uses a blank prefix for submodules that are up
+        # to date
+        if out[0] != ' ':
+            return Task.RUN_ME
+
+        return Task.SKIP_ME
+
+    def __str__(self):
+        return 'Submodule update: %s' % self.submodule
+
+def configure(cfg):
+    cfg.find_program('git')
+
+_submodules_tasks = {}
+
+@taskgen_method
+def git_submodule_update(self, name):
+    if name not in _submodules_tasks:
+        module_node = self.bld.srcnode.make_node(os.path.join('modules', name))
+
+        tsk = self.create_task('update_submodule', submodule=name)
+        tsk.env.SRC_ROOT = self.bld.srcnode.abspath()
+        tsk.env.SUBMODULE_PATH = module_node.abspath()
+
+        _submodules_tasks[name] = tsk
+
+    return _submodules_tasks[name]
+
+
+@feature('git_submodule')
+@before_method('process_source')
+def process_module_dependencies(self):
+    self.git_submodule = getattr(self, 'git_submodule', '')
+    if not self.git_submodule:
+        self.bld.fatal('git_submodule: empty or missing git_submodule argument')
+    self.git_submodule_update(self.git_submodule)
+
+@conf
+def git_submodule(bld, git_submodule, **kw):
+    kw['git_submodule'] = git_submodule
+    kw['features'] = Utils.to_list(kw.get('features', ''))
+    kw['features'].append('git_submodule')
+
+    return bld(**kw)