#! /usr/bin/env python
# encoding: utf-8
# Thomas Nagy, 2014-2015 (ita)

"""
Climb dependencies without using build groups and without annotating them.

In practice, one may want to avoid this:
* This adds some overhead as the task generators have to be searched and processed
* This is also unlikely to work in the real-world (complex targets, not all dependencies are file-based, etc)
* This also makes the dependencies more complicated to understand when reading a wscript file (what requires what?)

This example will create "d.txt" and all the required files but no "aa*.txt".
The target "john" is hard-coded below, just call "waf", or comment the line to call "waf --targets=john"
"""

VERSION='0.0.1'
APPNAME='file_climbing'

top = '.'
out = 'build'

def options(opt):
	return

def configure(conf):
	return

def build(bld):
	for i in range(10):
		bld(rule='cp ${SRC} ${TGT}', source='a.txt', target='aa%d.txt' % i)
	bld(rule='cp ${SRC} ${TGT}', source='a.txt', target='b.txt')
	bld(rule='cp ${SRC} ${TGT}', source='b.txt', target='c.txt')
	bld(rule='cp ${SRC} ${TGT}', source='c.txt', target='d.txt', name='john')

	# HERE
	bld.targets = 'john'

import os
from waflib import Utils
from waflib.TaskGen import before_method, feature

@feature('*')
@before_method('process_source', 'process_rule')
def post_other_task_generators_if_necessary(self):

	if not self.bld.targets:
		return

	if not getattr(self, 'source', None):
		return

	group = self.bld.get_group(self.bld.get_group_idx(self))
	for x in Utils.to_list(self.source):
		y = os.path.split(x)[1]

		for tg in group:
			if id(tg) == id(self):
				continue

			if getattr(tg, 'target', None):
				pass

			for target in Utils.to_list(tg.target):
				y2 = os.path.split(target)[1]

				if y == y2:
					tg.post()