# __COPYRIGHT__
#
# Benchmarks for testing various possible implementations of the
# env.__setitem__() method(s) in the src/engine/SCons/Environment.py
# module.

from __future__ import print_function

import os.path
import re
import sys
import timeit

# Utility Timing class and function from:
# ASPN: Python Cookbook : Timing various python statements
# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/544297
#
# These wrap the basic timeit function to make it a little more
# convenient to do side-by-side tests of code.

class Timing:
    def __init__(self, name, num, init, statement):
        self.__timer = timeit.Timer(statement, init)
        self.__num   = num
        self.name    = name
        self.statement = statement
        self.__result  = None
        
    def timeit(self):
        self.__result = self.__timer.timeit(self.__num)
        
    def getResult(self):
        return self.__result

def times(num=1000000, init='', title='Results:', **statements):
    # time each statement
    timings = []
    for n, s in statements.items():
        t = Timing(n, num, init, s)
        t.timeit()
        timings.append(t)

    print()
    print(title)
    for i in sorted([(i.getResult(),i.name) for i in timings]):
        print("  %9.3f s   %s" % i)

# Import the necessary local SCons.* modules used by some of our
# alternative implementations below, first manipulating sys.path so
# we pull in the right local modules without forcing the user to set
# PYTHONPATH.

import __main__
try:
    filename = __main__.__file__
except AttributeError:
    filename = sys.argv[0]
script_dir = os.path.split(filename)[0]
if script_dir:
    script_dir = script_dir + '/'
sys.path = [os.path.abspath(script_dir + '../src/engine')] + sys.path

import SCons.Errors
import SCons.Environment

is_valid_construction_var = SCons.Environment.is_valid_construction_var
global_valid_var = re.compile(r'[_a-zA-Z]\w*$')

# The classes with different __setitem__() implementations that we're
# going to horse-race.
#
# The base class (Environment) should contain *all* class initialization
# of anything that will be used by any of the competing sub-class
# implementations.  Each timing run will create an instance of the class,
# and all competing sub-classes should share the same initialization
# overhead so our timing focuses on just the __setitem__() performance.
#
# All subclasses should be prefixed with env_, in which case they'll be
# picked up automatically by the code below for testing.
#
# The env_Original subclass contains the original implementation (which
# actually had the is_valid_construction_var() function in SCons.Util
# originally).
#
# The other subclasses (except for env_Best) each contain *one*
# significant change from the env_Original implementation.  The doc string
# describes the change, and is what gets displayed in the final timing.
# The doc strings of these other subclasses are "grouped" informally
# by a prefix that kind of indicates what specific aspect of __setitem__()
# is being varied and tested.
#
# The env_Best subclass contains the "best practices" from each of
# the different "groups" of techniques tested in the other subclasses,
# and is where to experiment with different combinations of techniques.
# After we're done should be the one that shows up at the top of the
# list as we run our timings.

class Environment:
    _special_set = {
        'BUILDERS' : None,
        'SCANNERS' : None,
        'TARGET'   : None,
        'TARGETS'  : None,
        'SOURCE'   : None,
        'SOURCES'  : None,
    }
    _special_set_keys = list(_special_set.keys())
    _valid_var = re.compile(r'[_a-zA-Z]\w*$')
    def __init__(self, **kw):
        self._dict = kw

class env_Original(Environment):
    """Original __setitem__()"""
    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            if not SCons.Environment.is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_Global_is_valid(Environment):
    """is_valid_construction_var():  use a global function"""
    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            if not is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_Method_is_valid(Environment):
    """is_valid_construction_var():  use a method"""
    def is_valid_construction_var(self, varstr):
        """Return if the specified string is a legitimate construction
        variable.
        """
        return self._valid_var.match(varstr)

    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            if not self.is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_regex_attribute_is_valid(Environment):
    """is_valid_construction_var():  use a regex attribute"""
    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            if not self._valid_var.match(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_global_regex_is_valid(Environment):
    """is_valid_construction_var():  use a global regex"""
    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            if not global_valid_var.match(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_special_set_has_key(Environment):
    """_special_set.get():  use _special_set.has_key() instead"""
    def __setitem__(self, key, value):
        if key in self._special_set:
            self._special_set[key](self, key, value)
        else:
            if not SCons.Environment.is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_key_in_tuple(Environment):
    """_special_set.get():  use "key in tuple" instead"""
    def __setitem__(self, key, value):
        if key in ('BUILDERS', 'SCANNERS', 'TARGET', 'TARGETS', 'SOURCE', 'SOURCES'):
            self._special_set[key](self, key, value)
        else:
            if not SCons.Environment.is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_key_in_list(Environment):
    """_special_set.get():  use "key in list" instead"""
    def __setitem__(self, key, value):
        if key in ['BUILDERS', 'SCANNERS', 'TARGET', 'TARGETS', 'SOURCE', 'SOURCES']:
            self._special_set[key](self, key, value)
        else:
            if not SCons.Environment.is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_key_in_attribute(Environment):
    """_special_set.get():  use "key in attribute" instead"""
    def __setitem__(self, key, value):
        if key in self._special_set_keys:
            self._special_set[key](self, key, value)
        else:
            if not SCons.Environment.is_valid_construction_var(key):
                raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_try_except(Environment):
    """avoid is_valid_construction_var():  use try:-except:"""
    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            try:
                self._dict[key]
            except KeyError:
                if not SCons.Environment.is_valid_construction_var(key):
                    raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_not_has_key(Environment):
    """avoid is_valid_construction_var():  use not .has_key()"""
    def __setitem__(self, key, value):
        special = self._special_set.get(key)
        if special:
            special(self, key, value)
        else:
            if key not in self._dict \
                and not SCons.Environment.is_valid_construction_var(key):
                    raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_Best_attribute(Environment):
    """Best __setitem__(), with an attribute"""
    def __setitem__(self, key, value):
        if key in self._special_set_keys:
            self._special_set[key](self, key, value)
        else:
            if key not in self._dict \
               and not global_valid_var.match(key):
                    raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_Best_has_key(Environment):
    """Best __setitem__(), with has_key"""
    def __setitem__(self, key, value):
        if key in self._special_set:
            self._special_set[key](self, key, value)
        else:
            if key not in self._dict \
               and not global_valid_var.match(key):
                    raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

class env_Best_list(Environment):
    """Best __setitem__(), with a list"""
    def __setitem__(self, key, value):
        if key in ['BUILDERS', 'SCANNERS', 'TARGET', 'TARGETS', 'SOURCE', 'SOURCES']:
            self._special_set[key](self, key, value)
        else:
            if key not in self._dict \
               and not global_valid_var.match(key):
                    raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
            self._dict[key] = value

try:
    ''.isalnum
except AttributeError:
    pass
else:
    class env_isalnum(Environment):
        """Greg's Folly: isalnum instead of probe"""
        def __setitem__(self, key, value):
            if key in self._special_set:
                self._special_set[key](self, key, value)
            else:
                if not key.isalnum() and not global_valid_var.match(key):
                    raise SCons.Errors.UserError("Illegal construction variable `%s'" % key)
                self._dict[key] = value

# We'll use the names of all the env_* classes we find later to build
# the dictionary of statements to be timed, and the import statement
# that the timer will use to get at these classes.

class_names = []
for n in list(locals().keys()):
    #if n.startswith('env_'):
    if n[:4] == 'env_':
        class_names.append(n)

# This is *the* function that gets timed.  It will get called for the
# specified number of iterations for the cross product of the number of
# classes we're testing and the number of data sets (defined below).

iterations = 10000

def do_it(names, env_class):
    e = env_class()
    for key in names:
        e[key] = 1

# Build the list of "statements" that will be tested.  For each class
# we're testing, the doc string describing the class is the key, and
# the statement we test is a simple "doit(names, {class})" call.

statements = {}

for class_name in class_names:
    ec = eval(class_name)
    statements[ec.__doc__] = 'do_it(names, %s)' % class_name

# The common_imports string is used in the initialization of each
# test run.  The timeit module insulates the test snippets from the
# global namespace, so we have to import these explicitly from __main__.

common_import_variables = ['do_it'] + class_names

common_imports = """
from __main__ import %s
""" % ', '.join(common_import_variables)

# The test data (lists of variable names) that we'll use for the runs.

same_variable_names = ['XXX'] * 100
uniq_variable_names = []
for i in range(100): uniq_variable_names.append('X%05d' % i)
mixed_variable_names = uniq_variable_names[:50] + same_variable_names[:50]

# Lastly, put it all together...

def run_it(title, init):
      s = statements.copy()
      s['num'] = iterations
      s['title'] = title
      s['init'] = init
      times(**s)

print('Environment __setitem__ benchmark using', end=' ')
print('Python', sys.version.split()[0], end=' ')
print('on', sys.platform, os.name)

run_it('Results for re-adding an existing variable name 100 times:',
      common_imports + """
import __main__ ; names = __main__.same_variable_names
""")

run_it('Results for adding 100 variable names, 50 existing and 50 new:',
      common_imports + """
import __main__ ; names = __main__.mixed_variable_names
""")

run_it('Results for adding 100 new, unique variable names:',
      common_imports + """
import __main__ ; names = __main__.uniq_variable_names
""")

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