1 files changed, 216 insertions, 0 deletions
diff --git a/codegen/vulkan/scripts/spec_tools/validity.py b/codegen/vulkan/scripts/spec_tools/validity.py
new file mode 100644
index 00000000..745ba013
--- /dev/null
+++ b/codegen/vulkan/scripts/spec_tools/validity.py
@@ -0,0 +1,216 @@
+#!/usr/bin/python3 -i
+#
+# Copyright 2013-2021 The Khronos Group Inc.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+import re
+
+
+_A_VS_AN_RE = re.compile(r' a ([a-z]+:)?([aAeEiIoOxX]\w+\b)(?!:)')
+
+_STARTS_WITH_MACRO_RE = re.compile(r'^[a-z]+:.*')
+
+
+def _checkAnchorComponents(anchor):
+    """Raise an exception if any component of a VUID anchor name is illegal."""
+    if anchor:
+        # Any other invalid things in an anchor name should be detected here.
+        if any((' ' in anchor_part for anchor_part in anchor)):
+            raise RuntimeError("Illegal component of a VUID anchor name!")
+
+
+def _fix_a_vs_an(s):
+    """Fix usage (often generated) of the indefinite article 'a' when 'an' is appropriate.
+
+    Explicitly excludes the markup macros."""
+    return _A_VS_AN_RE.sub(r' an \1\2', s)
+
+
+class ValidityCollection:
+    """Combines validity for a single entity."""
+
+    def __init__(self, entity_name=None, conventions=None, strict=True):
+        self.entity_name = entity_name
+        self.conventions = conventions
+        self.lines = []
+        self.strict = strict
+
+    def possiblyAddExtensionRequirement(self, extension_name, entity_preface):
+        """Add an extension-related validity statement if required.
+
+        entity_preface is a string that goes between "must be enabled prior to "
+        and the name of the entity, and normally ends in a macro.
+        For instance, might be "calling flink:" for a function.
+        """
+        if extension_name and not extension_name.startswith(self.conventions.api_version_prefix):
+            msg = 'The {} extension must: be enabled prior to {}{}'.format(
+                self.conventions.formatExtension(extension_name), entity_preface, self.entity_name)
+            self.addValidityEntry(msg, anchor=('extension', 'notenabled'))
+
+    def addValidityEntry(self, msg, anchor=None):
+        """Add a validity entry, optionally with a VUID anchor.
+
+        If any trailing arguments are supplied,
+        an anchor is generated by concatenating them with dashes
+        at the end of the VUID anchor name.
+        """
+        if not msg:
+            raise RuntimeError("Tried to add a blank validity line!")
+        parts = ['*']
+        _checkAnchorComponents(anchor)
+        if anchor:
+            if not self.entity_name:
+                raise RuntimeError('Cannot add a validity entry with an anchor to a collection that does not know its entity name.')
+            parts.append('[[{}]]'.format(
+                '-'.join(['VUID', self.entity_name] + list(anchor))))
+        parts.append(msg)
+        combined = _fix_a_vs_an(' '.join(parts))
+        if combined in self.lines:
+            raise RuntimeError("Duplicate validity added!")
+        self.lines.append(combined)
+
+    def addText(self, msg):
+        """Add already formatted validity text."""
+        if self.strict:
+            raise RuntimeError('addText called when collection in strict mode')
+        if not msg:
+            return
+        msg = msg.rstrip()
+        if not msg:
+            return
+        self.lines.append(msg)
+
+    def _extend(self, lines):
+        lines = list(lines)
+        dupes = set(lines).intersection(self.lines)
+        if dupes:
+            raise RuntimeError("The two sets contain some shared entries! " + str(dupes))
+        self.lines.extend(lines)
+
+    def __iadd__(self, other):
+        """Perform += with a string, iterable, or ValidityCollection."""
+        if other is None:
+            pass
+        elif isinstance(other, str):
+            if self.strict:
+                raise RuntimeError(
+                    'Collection += a string when collection in strict mode')
+            if not other:
+                # empty string
+                pass
+            elif other.startswith('*'):
+                # Handle already-formatted
+                self.addText(other)
+            else:
+                # Do the formatting ourselves.
+                self.addValidityEntry(other)
+        elif isinstance(other, ValidityEntry):
+            if other:
+                if other.verbose:
+                    print(self.entity_name, 'Appending', str(other))
+                self.addValidityEntry(str(other), anchor=other.anchor)
+        elif isinstance(other, ValidityCollection):
+            if not self.entity_name == other.entity_name:
+                raise RuntimeError(
+                    "Trying to combine two ValidityCollections for different entities!")
+            self._extend(other.lines)
+        else:
+            # Deal with other iterables.
+            self._extend(other)
+
+        return self
+
+    def __bool__(self):
+        """Is the collection non-empty?"""
+        empty = not self.lines
+        return not empty
+
+    @property
+    def text(self):
+        """Access validity statements as a single string or None."""
+        if not self.lines:
+            return None
+        return '\n'.join(self.lines) + '\n'
+
+    def __str__(self):
+        """Access validity statements as a single string or empty string."""
+        if not self:
+            return ''
+        return self.text
+
+    def __repr__(self):
+        return '<ValidityCollection: {}>'.format(self.lines)
+
+
+class ValidityEntry:
+    """A single validity line in progress."""
+
+    def __init__(self, text=None, anchor=None):
+        """Prepare to add a validity entry, optionally with a VUID anchor.
+
+        An anchor is generated by concatenating the elements of the anchor tuple with dashes
+        at the end of the VUID anchor name.
+        """
+        _checkAnchorComponents(anchor)
+        if isinstance(anchor, str):
+            # anchor needs to be a tuple
+            anchor = (anchor,)
+
+        # VUID does not allow special chars except ":"
+        if anchor is not None:
+            anchor = [(anchor_value.replace('->', '::').replace('.', '::')) for anchor_value in anchor]
+
+        self.anchor = anchor
+        self.parts = []
+        self.verbose = False
+        if text:
+            self.append(text)
+
+    def append(self, part):
+        """Append a part of a string.
+
+        If this is the first entry part and the part doesn't start
+        with a markup macro, the first character will be capitalized."""
+        if not self.parts and not _STARTS_WITH_MACRO_RE.match(part):
+            self.parts.append(part[:1].upper())
+            self.parts.append(part[1:])
+        else:
+            self.parts.append(part)
+        if self.verbose:
+            print('ValidityEntry', id(self), 'after append:', str(self))
+
+    def drop_end(self, n):
+        """Remove up to n trailing characters from the string."""
+        temp = str(self)
+        n = min(len(temp), n)
+        self.parts = [temp[:-n]]
+
+    def __iadd__(self, other):
+        """Perform += with a string,"""
+        self.append(other)
+        return self
+
+    def __bool__(self):
+        """Return true if we have something more than just an anchor."""
+        empty = not self.parts
+        return not empty
+
+    def __str__(self):
+        """Access validity statement as a single string or empty string."""
+        if not self:
+            raise RuntimeError("No parts added?")
+        return ''.join(self.parts).strip()
+
+    def __repr__(self):
+        parts = ['<ValidityEntry: ']
+        if self:
+            parts.append('"')
+            parts.append(str(self))
+            parts.append('"')
+        else:
+            parts.append('EMPTY')
+        if self.anchor:
+            parts.append(', anchor={}'.format('-'.join(self.anchor)))
+        parts.append('>')
+        return ''.join(parts)