framework/replay/backends/__init__.py

   1 # coding=utf-8
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   3 # Copyright (c) 2014-2016, 2019 Intel Corporation
   4 # Copyright © 2019-2020 Valve Corporation.
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  24 # SPDX-License-Identifier: MIT
  25
  26 """Provides a module like interface for dump backends.
  27
  28 This package provides an abstract interface for working with dump backends,
  29 which implement various functions as provided in the Registry class, and then
  30 provide a Registry instance as REGISTRY, which maps individual objects to
  31 objects that piglit expects to use. This module then provides a thin
  32 abstraction layer so that piglit is never aware of what backend it's using, it
  33 just asks for an object and receives one.
  34
  35 Most consumers will want to import framework.replay.backends and work directly
  36 with the helper functions here. For some more detailed uses (test cases
  37 especially) the modules themselves may be used.
  38
  39 When this module is loaded it will search through framework/replay/backends for
  40 python modules (those ending in .py), and attempt to import them. Then it will
  41 look for an attribute REGISTRY in those modules, and if it as a
  42 framework.replay.register.Registry instance, it will add the name of that
  43 module (sans .py) as a key, and the instance as a value to the DUMPBACKENDS
  44 dictionary. Each of the helper functions in this module uses that dictionary to
  45 find the function that a user actually wants.
  46
  47 """
  48
  49 import importlib
  50 import os
  51 from os import path
  52
  53 from .register import Registry
  54
  55 __all__ = [
  56     'DUMPBACKENDS',
  57     'DumpBackendError',
  58     'DumpBackendNotImplementedError',
  59     'dump',
  60 ]
  61
  62
  63 class DumpBackendError(Exception):
  64     pass
  65
  66
  67 class DumpBackendNotImplementedError(NotImplementedError):
  68     pass
  69
  70
  71 def _register():
  72     """Register backends.
  73
  74     Walk through the list of backends and register them to a name in a
  75     dictionary, so that they can be referenced from helper functions.
  76
  77     """
  78     registry = {}
  79
  80     for module in os.listdir(path.dirname(path.abspath(__file__))):
  81         module, extension = path.splitext(module)
  82         if extension == '.py':
  83             mod = importlib.import_module(
  84                 'framework.replay.backends.{}'.format(module))
  85             if hasattr(mod, 'REGISTRY') and isinstance(mod.REGISTRY, Registry):
  86                 registry[module] = mod.REGISTRY
  87
  88     return registry
  89
  90
  91 DUMPBACKENDS = _register()
  92
  93
  94 def dump(trace_path, output_dir=None, calls=None):
  95     """Wrapper for dumping traces.
  96
  97     This function will attempt to determine how to dump the trace file (based
  98     on file extension), and then pass the trace file path, output_dir and calls
  99     into the appropriate instance, and then call dump in such instance.
 100
 101     """
 102     name, extension = path.splitext(trace_path)
 103
 104     for dump_backend in DUMPBACKENDS.values():
 105         if extension in dump_backend.extensions:
 106             backend = dump_backend.backend
 107
 108             if backend is None:
 109                 raise DumpBackendNotImplementedError(
 110                     'DumpBackend for "{}" is not implemented'.format(extension))
 111
 112             instance = backend(trace_path, output_dir, calls)
 113             return instance.dump()
 114
 115     raise DumpBackendError(
 116         'No module supports file extensions "{}"'.format(extension))