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| 1 #!/usr/bin/python2.4 | |
| 2 # Copyright 2008, Google Inc. | |
| 3 # All rights reserved. | |
| 4 # | |
| 5 # Redistribution and use in source and binary forms, with or without | |
| 6 # modification, are permitted provided that the following conditions are | |
| 7 # met: | |
| 8 # | |
| 9 # * Redistributions of source code must retain the above copyright | |
| 10 # notice, this list of conditions and the following disclaimer. | |
| 11 # * Redistributions in binary form must reproduce the above | |
| 12 # copyright notice, this list of conditions and the following disclaimer | |
| 13 # in the documentation and/or other materials provided with the | |
| 14 # distribution. | |
| 15 # * Neither the name of Google Inc. nor the names of its | |
| 16 # contributors may be used to endorse or promote products derived from | |
| 17 # this software without specific prior written permission. | |
| 18 # | |
| 19 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 20 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 21 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 22 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 23 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 24 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 25 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 26 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 27 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 28 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 29 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 30 | |
| 31 """Defer tool for SCons.""" | |
| 32 | |
| 33 | |
| 34 import os | |
| 35 import sys | |
| 36 import types | |
| 37 import SCons.Errors | |
| 38 | |
| 39 | |
| 40 # Current group name being executed by ExecuteDefer(). Set to None outside | |
| 41 # of ExecuteDefer(). | |
| 42 _execute_defer_context = None | |
| 43 | |
| 44 | |
| 45 class DeferGroup: | |
| 46 """Named list of functions to be deferred.""" | |
| 47 # If we derive DeferGroup from object, instances of it return type | |
| 48 # <class 'defer.DeferGroup'>, which prevents SCons.Util.semi_deepcopy() | |
| 49 # from calling its __semi_deepcopy__ function. | |
| 50 # TODO(sgk): Make semi_deepcopy() capable of handling classes derived from | |
| 51 # object. | |
| 52 | |
| 53 def __init__(self): | |
| 54 """Initialize deferred function object.""" | |
| 55 self.func_env_cwd = [] | |
| 56 self.after = set() | |
| 57 | |
| 58 def __semi_deepcopy__(self): | |
| 59 """Makes a semi-deep-copy of this object. | |
| 60 | |
| 61 Returns: | |
| 62 A semi-deep-copy of this object. | |
| 63 | |
| 64 This means it copies the sets and lists contained by this object, but | |
| 65 doesn't make copies of the function pointers and environments pointed to by | |
| 66 those lists. | |
| 67 | |
| 68 Needed so env.Clone() makes a copy of the defer list, so that functions | |
| 69 and after-relationships subsequently added to the clone are not added to | |
| 70 the parent. | |
| 71 """ | |
| 72 c = DeferGroup() | |
| 73 c.func_env_cwd = self.func_env_cwd[:] | |
| 74 c.after = self.after.copy() | |
| 75 return c | |
| 76 | |
| 77 | |
| 78 def SetDeferRoot(self): | |
| 79 """Sets the current environment as the root environment for defer. | |
| 80 | |
| 81 Args: | |
| 82 self: Current environment context. | |
| 83 | |
| 84 Functions deferred by environments cloned from the root environment (that is, | |
| 85 function deferred by children of the root environment) will be executed when | |
| 86 ExecuteDefer() is called from the root environment. | |
| 87 | |
| 88 Functions deferred by environments from which the root environment was cloned | |
| 89 (that is, functions deferred by parents of the root environment) will be | |
| 90 passed the root environment instead of the original parent environment. | |
| 91 (Otherwise, they would have no way to determine the root environment.) | |
| 92 """ | |
| 93 # Set the current environment as the root for holding defer groups | |
| 94 self['_DEFER_ROOT_ENV'] = self | |
| 95 | |
| 96 # Deferred functions this environment got from its parents will be run in the | |
| 97 # new root context. | |
| 98 for group in GetDeferGroups(self).values(): | |
| 99 new_list = [(func, self, cwd) for (func, env, cwd) in group.func_env_cwd] | |
| 100 group.func_env_cwd = new_list | |
| 101 | |
| 102 | |
| 103 def GetDeferRoot(self): | |
| 104 """Returns the root environment for defer. | |
| 105 | |
| 106 Args: | |
| 107 self: Current environment context. | |
| 108 | |
| 109 Returns: | |
| 110 The root environment for defer. If one of this environment's parents | |
| 111 called SetDeferRoot(), returns that environment. Otherwise returns the | |
| 112 current environment. | |
| 113 """ | |
| 114 return self.get('_DEFER_ROOT_ENV', self) | |
| 115 | |
| 116 | |
| 117 def GetDeferGroups(env): | |
| 118 """Returns the dict of defer groups from the root defer environment. | |
| 119 | |
| 120 Args: | |
| 121 env: Environment context. | |
| 122 | |
| 123 Returns: | |
| 124 The dict of defer groups from the root defer environment. | |
| 125 """ | |
| 126 return env.GetDeferRoot()['_DEFER_GROUPS'] | |
| 127 | |
| 128 | |
| 129 def ExecuteDefer(self): | |
| 130 """Executes deferred functions. | |
| 131 | |
| 132 Args: | |
| 133 self: Current environment context. | |
| 134 """ | |
| 135 # Check for re-entrancy | |
| 136 global _execute_defer_context | |
| 137 if _execute_defer_context: | |
| 138 raise SCons.Errors.UserError('Re-entrant call to ExecuteDefer().') | |
| 139 | |
| 140 # Save directory, so SConscript functions can occur in the right subdirs | |
| 141 oldcwd = os.getcwd() | |
| 142 | |
| 143 # If defer root is set and isn't this environment, we're being called from a | |
| 144 # sub-environment. That's not where we should be called. | |
| 145 if self.GetDeferRoot() != self: | |
| 146 print ('Warning: Ignoring call to ExecuteDefer() from child of the ' | |
| 147 'environment passed to SetDeferRoot().') | |
| 148 return | |
| 149 | |
| 150 # Get list of defer groups from ourselves. | |
| 151 defer_groups = GetDeferGroups(self) | |
| 152 | |
| 153 # Loop through deferred functions | |
| 154 try: | |
| 155 while defer_groups: | |
| 156 did_work = False | |
| 157 for name, group in defer_groups.items(): | |
| 158 if group.after.intersection(defer_groups.keys()): | |
| 159 continue # Still have dependencies | |
| 160 | |
| 161 # Set defer context | |
| 162 _execute_defer_context = name | |
| 163 | |
| 164 # Remove this group from the list of defer groups now, in case one of | |
| 165 # the functions it calls adds back a function into that defer group. | |
| 166 del defer_groups[name] | |
| 167 | |
| 168 if group.func_env_cwd: | |
| 169 # Run all the functions in our named group | |
| 170 for func, env, cwd in group.func_env_cwd: | |
| 171 os.chdir(cwd) | |
| 172 func(env) | |
| 173 | |
| 174 # The defer groups have been altered, so restart the search for | |
| 175 # functions that can be executed. | |
| 176 did_work = True | |
| 177 break | |
| 178 | |
| 179 if not did_work: | |
| 180 errmsg = 'Error in ExecuteDefer: dependency cycle detected.\n' | |
| 181 for name, group in defer_groups.items(): | |
| 182 errmsg += ' %s after: %s\n' % (name, group.after) | |
| 183 raise SCons.Errors.UserError(errmsg) | |
| 184 finally: | |
| 185 # No longer in a defer context | |
| 186 _execute_defer_context = None | |
| 187 | |
| 188 # Restore directory | |
| 189 os.chdir(oldcwd) | |
| 190 | |
| 191 | |
| 192 def PrintDefer(self, print_functions=True): | |
| 193 """Prints the current defer dependency graph. | |
| 194 | |
| 195 Args: | |
| 196 self: Environment in which PrintDefer() was called. | |
| 197 print_functions: Print individual functions in defer groups. | |
| 198 """ | |
| 199 # Get the defer dict | |
| 200 # Get list of defer groups from ourselves. | |
| 201 defer_groups = GetDeferGroups(self) | |
| 202 dgkeys = defer_groups.keys() | |
| 203 dgkeys.sort() | |
| 204 for k in dgkeys: | |
| 205 print ' +- %s' % k | |
| 206 group = defer_groups[k] | |
| 207 after = list(group.after) | |
| 208 if after: | |
| 209 print ' | after' | |
| 210 after.sort() | |
| 211 for a in after: | |
| 212 print ' | +- %s' % a | |
| 213 if print_functions and group.func_env_cwd: | |
| 214 print ' functions' | |
| 215 for func, env, cwd in group.func_env_cwd: | |
| 216 print ' | +- %s %s' % (func.__name__, cwd) | |
| 217 | |
| 218 | |
| 219 def Defer(self, *args, **kwargs): | |
| 220 """Adds a deferred function or modifies defer dependencies. | |
| 221 | |
| 222 Args: | |
| 223 self: Environment in which Defer() was called | |
| 224 args: Positional arguments | |
| 225 kwargs: Named arguments | |
| 226 | |
| 227 The deferred function will be passed the environment used to call Defer(), | |
| 228 and will be executed in the same working directory as the calling SConscript. | |
| 229 (Exception: if this environment is cloned and the clone calls SetDeferRoot() | |
| 230 and then ExecuteDefer(), the function will be passed the root environment, | |
| 231 instead of the environment used to call Defer().) | |
| 232 | |
| 233 All deferred functions run after all SConscripts. Additional dependencies | |
| 234 may be specified with the after= keyword. | |
| 235 | |
| 236 Usage: | |
| 237 | |
| 238 env.Defer(func) | |
| 239 # Defer func() until after all SConscripts | |
| 240 | |
| 241 env.Defer(func, after=otherfunc) | |
| 242 # Defer func() until otherfunc() runs | |
| 243 | |
| 244 env.Defer(func, 'bob') | |
| 245 # Defer func() until after SConscripts, put in group 'bob' | |
| 246 | |
| 247 env.Defer(func2, after='bob') | |
| 248 # Defer func2() until after all funcs in 'bob' group have run | |
| 249 | |
| 250 env.Defer(func3, 'sam') | |
| 251 # Defer func3() until after SConscripts, put in group 'sam' | |
| 252 | |
| 253 env.Defer('bob', after='sam') | |
| 254 # Defer all functions in group 'bob' until after all functions in group | |
| 255 # 'sam' have run. | |
| 256 | |
| 257 env.Defer(func4, after=['bob', 'sam']) | |
| 258 # Defer func4() until after all functions in groups 'bob' and 'sam' have | |
| 259 # run. | |
| 260 """ | |
| 261 # Get name of group to defer and/or the a function | |
| 262 name = None | |
| 263 func = None | |
| 264 for a in args: | |
| 265 if isinstance(a, str): | |
| 266 name = a | |
| 267 elif isinstance(a, types.FunctionType): | |
| 268 func = a | |
| 269 if func and not name: | |
| 270 name = func.__name__ | |
| 271 | |
| 272 # TODO(rspangler): Why not allow multiple functions? Should be ok | |
| 273 | |
| 274 # Get list of names and/or functions this function should defer until after | |
| 275 after = [] | |
| 276 for a in self.Flatten(kwargs.get('after')): | |
| 277 if isinstance(a, str): | |
| 278 # TODO(rspangler): Should check if '$' in a, and if so, subst() it and | |
| 279 # recurse into it. | |
| 280 after.append(a) | |
| 281 elif isinstance(a, types.FunctionType): | |
| 282 after.append(a.__name__) | |
| 283 elif a is not None: | |
| 284 # Deferring | |
| 285 raise ValueError('Defer after=%r is not a function or name' % a) | |
| 286 | |
| 287 # Find the deferred function | |
| 288 defer_groups = GetDeferGroups(self) | |
| 289 if name not in defer_groups: | |
| 290 defer_groups[name] = DeferGroup() | |
| 291 group = defer_groups[name] | |
| 292 | |
| 293 # If we were given a function, also save environment and current directory | |
| 294 if func: | |
| 295 group.func_env_cwd.append((func, self, os.getcwd())) | |
| 296 | |
| 297 # Add dependencies for the function | |
| 298 group.after.update(after) | |
| 299 | |
| 300 # If we are already inside a call to ExecuteDefer(), any functions which are | |
| 301 # deferring until after the current function must also be deferred until | |
| 302 # after this new function. In short, this means that if b() defers until | |
| 303 # after a() and a() calls Defer() to defer c(), then b() must also defer | |
| 304 # until after c(). | |
| 305 if _execute_defer_context and name != _execute_defer_context: | |
| 306 for other_name, other_group in GetDeferGroups(self).items(): | |
| 307 if other_name == name: | |
| 308 continue # Don't defer after ourselves | |
| 309 if _execute_defer_context in other_group.after: | |
| 310 other_group.after.add(name) | |
| 311 | |
| 312 | |
| 313 def generate(env): | |
| 314 # NOTE: SCons requires the use of this name, which fails gpylint. | |
| 315 """SCons entry point for this tool.""" | |
| 316 env.Append(_DEFER_GROUPS={}) | |
| 317 | |
| 318 env.AddMethod(Defer) | |
| 319 env.AddMethod(ExecuteDefer) | |
| 320 env.AddMethod(GetDeferRoot) | |
| 321 env.AddMethod(PrintDefer) | |
| 322 env.AddMethod(SetDeferRoot) | |
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