210 lines
7.9 KiB
Python
210 lines
7.9 KiB
Python
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#
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# Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
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# Use of this file is governed by the BSD 3-clause license that
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# can be found in the LICENSE.txt file in the project root.
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#
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# Specialized {@link Set}{@code <}{@link ATNConfig}{@code >} that can track
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# info about the set, with support for combining similar configurations using a
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# graph-structured stack.
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#/
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from io import StringIO
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from functools import reduce
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from antlr4.PredictionContext import PredictionContext, merge
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from antlr4.Utils import str_list
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from antlr4.atn.ATN import ATN
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from antlr4.atn.ATNConfig import ATNConfig
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from antlr4.atn.SemanticContext import SemanticContext
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from antlr4.error.Errors import UnsupportedOperationException, IllegalStateException
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ATNSimulator = None
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class ATNConfigSet(object):
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#
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# The reason that we need this is because we don't want the hash map to use
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# the standard hash code and equals. We need all configurations with the same
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# {@code (s,i,_,semctx)} to be equal. Unfortunately, this key effectively doubles
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# the number of objects associated with ATNConfigs. The other solution is to
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# use a hash table that lets us specify the equals/hashcode operation.
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def __init__(self, fullCtx:bool=True):
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# All configs but hashed by (s, i, _, pi) not including context. Wiped out
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# when we go readonly as this set becomes a DFA state.
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self.configLookup = dict()
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# Indicates that this configuration set is part of a full context
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# LL prediction. It will be used to determine how to merge $. With SLL
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# it's a wildcard whereas it is not for LL context merge.
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self.fullCtx = fullCtx
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# Indicates that the set of configurations is read-only. Do not
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# allow any code to manipulate the set; DFA states will point at
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# the sets and they must not change. This does not protect the other
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# fields; in particular, conflictingAlts is set after
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# we've made this readonly.
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self.readonly = False
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# Track the elements as they are added to the set; supports get(i)#/
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self.configs = []
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# TODO: these fields make me pretty uncomfortable but nice to pack up info together, saves recomputation
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# TODO: can we track conflicts as they are added to save scanning configs later?
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self.uniqueAlt = 0
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self.conflictingAlts = None
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# Used in parser and lexer. In lexer, it indicates we hit a pred
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# while computing a closure operation. Don't make a DFA state from this.
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self.hasSemanticContext = False
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self.dipsIntoOuterContext = False
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self.cachedHashCode = -1
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def __iter__(self):
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return self.configs.__iter__()
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# Adding a new config means merging contexts with existing configs for
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# {@code (s, i, pi, _)}, where {@code s} is the
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# {@link ATNConfig#state}, {@code i} is the {@link ATNConfig#alt}, and
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# {@code pi} is the {@link ATNConfig#semanticContext}. We use
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# {@code (s,i,pi)} as key.
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#
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# <p>This method updates {@link #dipsIntoOuterContext} and
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# {@link #hasSemanticContext} when necessary.</p>
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#/
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def add(self, config:ATNConfig, mergeCache=None):
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if self.readonly:
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raise Exception("This set is readonly")
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if config.semanticContext is not SemanticContext.NONE:
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self.hasSemanticContext = True
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if config.reachesIntoOuterContext > 0:
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self.dipsIntoOuterContext = True
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existing = self.getOrAdd(config)
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if existing is config:
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self.cachedHashCode = -1
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self.configs.append(config) # track order here
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return True
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# a previous (s,i,pi,_), merge with it and save result
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rootIsWildcard = not self.fullCtx
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merged = merge(existing.context, config.context, rootIsWildcard, mergeCache)
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# no need to check for existing.context, config.context in cache
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# since only way to create new graphs is "call rule" and here.
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# We cache at both places.
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existing.reachesIntoOuterContext = max(existing.reachesIntoOuterContext, config.reachesIntoOuterContext)
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# make sure to preserve the precedence filter suppression during the merge
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if config.precedenceFilterSuppressed:
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existing.precedenceFilterSuppressed = True
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existing.context = merged # replace context; no need to alt mapping
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return True
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def getOrAdd(self, config:ATNConfig):
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h = config.hashCodeForConfigSet()
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l = self.configLookup.get(h, None)
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if l is not None:
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r = next((cfg for cfg in l if config.equalsForConfigSet(cfg)), None)
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if r is not None:
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return r
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if l is None:
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l = [config]
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self.configLookup[h] = l
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else:
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l.append(config)
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return config
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def getStates(self):
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return set(c.state for c in self.configs)
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def getPredicates(self):
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return list(cfg.semanticContext for cfg in self.configs if cfg.semanticContext!=SemanticContext.NONE)
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def get(self, i:int):
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return self.configs[i]
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def optimizeConfigs(self, interpreter:ATNSimulator):
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if self.readonly:
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raise IllegalStateException("This set is readonly")
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if len(self.configs)==0:
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return
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for config in self.configs:
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config.context = interpreter.getCachedContext(config.context)
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def addAll(self, coll:list):
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for c in coll:
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self.add(c)
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return False
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def __eq__(self, other):
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if self is other:
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return True
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elif not isinstance(other, ATNConfigSet):
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return False
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same = self.configs is not None and \
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self.configs==other.configs and \
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self.fullCtx == other.fullCtx and \
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self.uniqueAlt == other.uniqueAlt and \
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self.conflictingAlts == other.conflictingAlts and \
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self.hasSemanticContext == other.hasSemanticContext and \
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self.dipsIntoOuterContext == other.dipsIntoOuterContext
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return same
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def __hash__(self):
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if self.readonly:
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if self.cachedHashCode == -1:
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self.cachedHashCode = self.hashConfigs()
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return self.cachedHashCode
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return self.hashConfigs()
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def hashConfigs(self):
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return reduce(lambda h, cfg: hash((h, cfg)), self.configs, 0)
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def __len__(self):
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return len(self.configs)
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def isEmpty(self):
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return len(self.configs)==0
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def __contains__(self, config):
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if self.configLookup is None:
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raise UnsupportedOperationException("This method is not implemented for readonly sets.")
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h = config.hashCodeForConfigSet()
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l = self.configLookup.get(h, None)
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if l is not None:
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for c in l:
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if config.equalsForConfigSet(c):
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return True
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return False
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def clear(self):
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if self.readonly:
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raise IllegalStateException("This set is readonly")
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self.configs.clear()
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self.cachedHashCode = -1
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self.configLookup.clear()
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def setReadonly(self, readonly:bool):
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self.readonly = readonly
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self.configLookup = None # can't mod, no need for lookup cache
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def __str__(self):
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with StringIO() as buf:
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buf.write(str_list(self.configs))
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if self.hasSemanticContext:
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buf.write(",hasSemanticContext=")
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buf.write(str(self.hasSemanticContext))
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if self.uniqueAlt!=ATN.INVALID_ALT_NUMBER:
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buf.write(",uniqueAlt=")
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buf.write(str(self.uniqueAlt))
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if self.conflictingAlts is not None:
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buf.write(",conflictingAlts=")
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buf.write(str(self.conflictingAlts))
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if self.dipsIntoOuterContext:
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buf.write(",dipsIntoOuterContext")
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return buf.getvalue()
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class OrderedATNConfigSet(ATNConfigSet):
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def __init__(self):
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super().__init__()
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