Support flatbuffer-based tree exports/imports

.pylintrc

@@ -1,7 +1,7 @@
 [MASTER]
 
 # Files or directories to be skipped. They should be base names, not paths.
-ignore=g4, grammars
+ignore=g4, grammars, FBRule_generated.py
 
 # A comma-separated list of package or module names from where C extensions may
 # be loaded. Extensions are loading into the active Python interpreter and may

grammarinator/cli.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2020-2023 Renata Hodovan, Akos Kiss.
+# Copyright (c) 2020-2024 Renata Hodovan, Akos Kiss.
 #
 # Licensed under the BSD 3-Clause License
 # <LICENSE.rst or https://opensource.org/licenses/BSD-3-Clause>.
@@ -10,7 +10,7 @@
 
 from inators.imp import import_object
 
-from .tool import JsonTreeCodec, PickleTreeCodec
+from .tool import FlatBuffersTreeCodec, JsonTreeCodec, PickleTreeCodec
 
 logger = logging.getLogger('grammarinator')
 
@@ -46,6 +46,7 @@ def add_encoding_errors_argument(parser):
 tree_formats = {
     'pickle': {'extension': 'grtp', 'codec_class': PickleTreeCodec},
     'json': {'extension': 'grtj', 'codec_class': JsonTreeCodec},
+    'flatbuffers': {'extension': 'grtf', 'codec_class': FlatBuffersTreeCodec},
 }
 
 

grammarinator/tool/__init__.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2023 Renata Hodovan, Akos Kiss.
+# Copyright (c) 2023-2024 Renata Hodovan, Akos Kiss.
 #
 # Licensed under the BSD 3-Clause License
 # <LICENSE.rst or https://opensource.org/licenses/BSD-3-Clause>.
@@ -9,4 +9,4 @@
 from .generator import DefaultGeneratorFactory, GeneratorFactory, GeneratorTool
 from .parser import ParserTool
 from .processor import ProcessorTool
-from .tree_codec import AnnotatedTreeCodec, JsonTreeCodec, PickleTreeCodec, TreeCodec
+from .tree_codec import AnnotatedTreeCodec, FlatBuffersTreeCodec, JsonTreeCodec, PickleTreeCodec, TreeCodec

grammarinator/tool/fbs/FBRule_generated.py

@@ -0,0 +1,178 @@
+# automatically generated by the FlatBuffers compiler, do not modify
+
+# namespace: fbs
+
+import flatbuffers
+from flatbuffers.compat import import_numpy
+np = import_numpy()
+
+class FBRuleType(object):
+    UnlexerRuleType = 0
+    UnparserRuleType = 1
+    UnparserRuleQuantifierType = 2
+    UnparserRuleQuantifiedType = 3
+    UnparserRuleAlternativeType = 4
+
+
+class FBRuleSize(object):
+    __slots__ = ['_tab']
+
+    @classmethod
+    def SizeOf(cls):
+        return 8
+
+    # FBRuleSize
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # FBRuleSize
+    def Depth(self): return self._tab.Get(flatbuffers.number_types.Int32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(0))
+    # FBRuleSize
+    def Tokens(self): return self._tab.Get(flatbuffers.number_types.Int32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(4))
+
+def CreateFBRuleSize(builder, depth, tokens):
+    builder.Prep(4, 8)
+    builder.PrependInt32(tokens)
+    builder.PrependInt32(depth)
+    return builder.Offset()
+
+
+class FBRule(object):
+    __slots__ = ['_tab']
+
+    @classmethod
+    def GetRootAs(cls, buf, offset=0):
+        n = flatbuffers.encode.Get(flatbuffers.packer.uoffset, buf, offset)
+        x = FBRule()
+        x.Init(buf, n + offset)
+        return x
+
+    @classmethod
+    def GetRootAsFBRule(cls, buf, offset=0):
+        """This method is deprecated. Please switch to GetRootAs."""
+        return cls.GetRootAs(buf, offset)
+    # FBRule
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # FBRule
+    def Type(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(4))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Int8Flags, o + self._tab.Pos)
+        return 0
+
+    # FBRule
+    def Name(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(6))
+        if o != 0:
+            return self._tab.String(o + self._tab.Pos)
+        return None
+
+    # FBRule
+    def Children(self, j):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(8))
+        if o != 0:
+            x = self._tab.Vector(o)
+            x += flatbuffers.number_types.UOffsetTFlags.py_type(j) * 4
+            x = self._tab.Indirect(x)
+            obj = FBRule()
+            obj.Init(self._tab.Bytes, x)
+            return obj
+        return None
+
+    # FBRule
+    def ChildrenLength(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(8))
+        if o != 0:
+            return self._tab.VectorLen(o)
+        return 0
+
+    # FBRule
+    def ChildrenIsNone(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(8))
+        return o == 0
+
+    # FBRule
+    def Src(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(10))
+        if o != 0:
+            return self._tab.String(o + self._tab.Pos)
+        return None
+
+    # FBRule
+    def Size(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(12))
+        if o != 0:
+            x = o + self._tab.Pos
+            obj = FBRuleSize()
+            obj.Init(self._tab.Bytes, x)
+            return obj
+        return None
+
+    # FBRule
+    def Idx(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(14))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Int32Flags, o + self._tab.Pos)
+        return 0
+
+    # FBRule
+    def Start(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(16))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Int32Flags, o + self._tab.Pos)
+        return 0
+
+    # FBRule
+    def Stop(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(18))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Int32Flags, o + self._tab.Pos)
+        return 0
+
+    # FBRule
+    def AltIdx(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(20))
+        if o != 0:
+            return self._tab.Get(flatbuffers.number_types.Int32Flags, o + self._tab.Pos)
+        return 0
+
+def FBRuleStart(builder):
+    builder.StartObject(9)
+
+def FBRuleAddType(builder, type):
+    builder.PrependInt8Slot(0, type, 0)
+
+def FBRuleAddName(builder, name):
+    builder.PrependUOffsetTRelativeSlot(1, flatbuffers.number_types.UOffsetTFlags.py_type(name), 0)
+
+def FBRuleAddChildren(builder, children):
+    builder.PrependUOffsetTRelativeSlot(2, flatbuffers.number_types.UOffsetTFlags.py_type(children), 0)
+
+def FBRuleStartChildrenVector(builder, numElems):
+    return builder.StartVector(4, numElems, 4)
+
+def FBRuleAddSrc(builder, src):
+    builder.PrependUOffsetTRelativeSlot(3, flatbuffers.number_types.UOffsetTFlags.py_type(src), 0)
+
+def FBRuleAddSize(builder, size):
+    builder.PrependStructSlot(4, flatbuffers.number_types.UOffsetTFlags.py_type(size), 0)
+
+def FBRuleAddIdx(builder, idx):
+    builder.PrependInt32Slot(5, idx, 0)
+
+def FBRuleAddStart(builder, start):
+    builder.PrependInt32Slot(6, start, 0)
+
+def FBRuleAddStop(builder, stop):
+    builder.PrependInt32Slot(7, stop, 0)
+
+def FBRuleAddAltIdx(builder, altIdx):
+    builder.PrependInt32Slot(8, altIdx, 0)
+
+def FBRuleEnd(builder):
+    return builder.EndObject()
+
+
+

grammarinator/tool/fbs/__init__.py

@@ -0,0 +1,8 @@
+# Copyright (c) 2024 Renata Hodovan, Akos Kiss.
+#
+# Licensed under the BSD 3-Clause License
+# <LICENSE.rst or https://opensource.org/licenses/BSD-3-Clause>.
+# This file may not be copied, modified, or distributed except
+# according to those terms.
+
+from .FBRule_generated import CreateFBRuleSize, FBRule, FBRuleAddAltIdx, FBRuleAddChildren, FBRuleAddIdx, FBRuleAddName, FBRuleAddSize, FBRuleAddSrc, FBRuleAddStart, FBRuleAddStop, FBRuleAddType, FBRuleEnd, FBRuleSize, FBRuleStart, FBRuleStartChildrenVector, FBRuleType

grammarinator/tool/resources/fbs/FBRule.fbs

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2024 Renata Hodovan, Akos Kiss.
+ *
+ * Licensed under the BSD 3-Clause License
+ * <LICENSE.rst or https://opensource.org/licenses/BSD-3-Clause>.
+ * This file may not be copied, modified, or distributed except
+ * according to those terms.
+ */
+
+/*
+ * This is the flatbuffer schema of the tree format of Grammarinator.
+ * It was used as input for the flatc compiler to generate code for
+ * building and reading flatbuffer tree representations
+ * (grammarinator/tool/fbs/FBRule_generated.py).
+ *
+ * The used flatc command:
+ * flatc --python --gen-onefile -o grammarinator/tool/fbs/ FBRule.fbs
+ */
+
+namespace grammarinator.tool.fbs;
+
+enum FBRuleType: byte {
+    UnlexerRuleType = 0,
+    UnparserRuleType = 1,
+    UnparserRuleQuantifierType = 2,
+    UnparserRuleQuantifiedType = 3,
+    UnparserRuleAlternativeType = 4
+}
+
+struct FBRuleSize {
+    depth: int;
+    tokens: int;
+}
+
+table FBRule {
+    type: FBRuleType;
+    name: string;
+    children: [FBRule];
+    src: string;
+    size: FBRuleSize;
+    idx: int;
+    start: int;
+    stop: int;
+    alt_idx: int;
+}
+
+root_type FBRule;

grammarinator/tool/tree_codec.py

@@ -7,8 +7,14 @@
 
 import json
 import pickle
+import struct
+
+from math import inf
+
+import flatbuffers
 
 from ..runtime import RuleSize, UnlexerRule, UnparserRule, UnparserRuleAlternative, UnparserRuleQuantified, UnparserRuleQuantifier
+from .fbs import CreateFBRuleSize, FBRule, FBRuleAddAltIdx, FBRuleAddChildren, FBRuleAddIdx, FBRuleAddName, FBRuleAddSize, FBRuleAddSrc, FBRuleAddStart, FBRuleAddStop, FBRuleAddType, FBRuleEnd, FBRuleStart, FBRuleStartChildrenVector, FBRuleType
 
 
 class TreeCodec:
@@ -153,3 +159,85 @@ def _dict_to_rule(dct):
             return json.loads(data.decode(encoding=self._encoding, errors=self._encoding_errors), object_hook=_dict_to_rule)
         except json.JSONDecodeError:
             return None
+
+
+class FlatBuffersTreeCodec(TreeCodec):
+    """
+    FlatBuffers-based tree codec.
+    """
+
+    def __init__(self, encoding='utf-8', encoding_errors='surrogatepass'):
+        """
+        :param str encoding: The encoding to use when converting between
+            flatbuffers-encoded text and bytes (default: utf-8).
+        """
+        self._encoding = encoding
+        self._encoding_errors = encoding_errors
+
+    def encode(self, root):
+        def buildFBRule(rule):
+            if isinstance(rule, UnlexerRule):
+                fb_name = builder.CreateString(rule.name, encoding=self._encoding, errors=self._encoding_errors)
+                fb_src = builder.CreateString(rule.src, encoding=self._encoding, errors=self._encoding_errors)
+                FBRuleStart(builder)
+                FBRuleAddType(builder, FBRuleType.UnlexerRuleType)
+                FBRuleAddName(builder, fb_name)
+                FBRuleAddSrc(builder, fb_src)
+                FBRuleAddSize(builder, CreateFBRuleSize(builder, rule.size.depth, rule.size.tokens))
+            else:
+                children = [buildFBRule(child) for child in rule.children]
+                FBRuleStartChildrenVector(builder, len(children))
+                for fb_child in reversed(children):
+                    builder.PrependUOffsetTRelative(fb_child)
+                fb_children = builder.EndVector()
+                if isinstance(rule, UnparserRule):
+                    fb_name = builder.CreateString(rule.name, encoding=self._encoding, errors=self._encoding_errors)
+                FBRuleStart(builder)
+                FBRuleAddChildren(builder, fb_children)
+                if isinstance(rule, UnparserRule):
+                    FBRuleAddName(builder, fb_name)
+                    FBRuleAddType(builder, FBRuleType.UnparserRuleType)
+                elif isinstance(rule, UnparserRuleQuantifier):
+                    FBRuleAddType(builder, FBRuleType.UnparserRuleQuantifierType)
+                    FBRuleAddIdx(builder, rule.idx)
+                    FBRuleAddStart(builder, rule.start)
+                    FBRuleAddStop(builder, rule.stop if rule.stop != inf else -1)
+                elif isinstance(rule, UnparserRuleQuantified):
+                    FBRuleAddType(builder, FBRuleType.UnparserRuleQuantifiedType)
+                elif isinstance(rule, UnparserRuleAlternative):
+                    FBRuleAddType(builder, FBRuleType.UnparserRuleAlternativeType)
+                    FBRuleAddAltIdx(builder, rule.alt_idx)
+                    FBRuleAddIdx(builder, rule.idx)
+            return FBRuleEnd(builder)
+
+        builder = flatbuffers.Builder()
+        builder.Finish(buildFBRule(root))
+        return bytes(builder.Output())
+
+    def decode(self, data):
+        def readFBRule(fb_rule):
+            rule_type = fb_rule.Type()
+            if rule_type == FBRuleType.UnlexerRuleType:
+                fb_size = fb_rule.Size()
+                rule = UnlexerRule(name=fb_rule.Name().decode(self._encoding, self._encoding_errors),
+                                   src=fb_rule.Src().decode(self._encoding, self._encoding_errors),
+                                   size=RuleSize(depth=fb_size.Depth(), tokens=fb_size.Tokens()))
+            else:
+                children = [readFBRule(fb_rule.Children(i)) for i in range(fb_rule.ChildrenLength())]
+                if rule_type == FBRuleType.UnparserRuleType:
+                    rule = UnparserRule(name=fb_rule.Name().decode(self._encoding, self._encoding_errors), children=children)
+                elif rule_type == FBRuleType.UnparserRuleQuantifierType:
+                    stop = fb_rule.Stop()
+                    rule = UnparserRuleQuantifier(idx=fb_rule.Idx(), start=fb_rule.Start(), stop=stop if stop != -1 else inf, children=children)
+                elif rule_type == FBRuleType.UnparserRuleQuantifiedType:
+                    rule = UnparserRuleQuantified(children=children)
+                elif rule_type == FBRuleType.UnparserRuleAlternativeType:
+                    rule = UnparserRuleAlternative(alt_idx=fb_rule.AltIdx(), idx=fb_rule.Idx(), children=children)
+                else:
+                    assert False, f'Unexpected type {rule_type}'
+            return rule
+
+        try:
+            return readFBRule(FBRule.GetRootAs(bytearray(data)))
+        except struct.error:
+            return None

setup.cfg

@@ -31,6 +31,7 @@ install_requires =
     antlerinator>=1!3.0.0
     antlr4-python3-runtime==4.13.1
     autopep8
+    flatbuffers
     inators
     jinja2
     regex