bpo-36876: Re-organize the c-analyzer tool code. (gh-16841)

This is partly a cleanup of the code. It also is preparation for getting the variables from the source (cross-platform) rather than from the symbols.

The change only touches the tool (and its tests).

Tools/c-analyzer/c_analyzer/common/util.py

@@ -0,0 +1,243 @@
+import csv
+import subprocess
+
+
+_NOT_SET = object()
+
+
+def run_cmd(argv, **kwargs):
+    proc = subprocess.run(
+            argv,
+            #capture_output=True,
+            #stderr=subprocess.STDOUT,
+            stdout=subprocess.PIPE,
+            text=True,
+            check=True,
+            **kwargs
+            )
+    return proc.stdout
+
+
+def read_tsv(infile, header, *,
+             _open=open,
+             _get_reader=csv.reader,
+             ):
+    """Yield each row of the given TSV (tab-separated) file."""
+    if isinstance(infile, str):
+        with _open(infile, newline='') as infile:
+            yield from read_tsv(infile, header,
+                                _open=_open,
+                                _get_reader=_get_reader,
+                                )
+            return
+    lines = iter(infile)
+
+    # Validate the header.
+    try:
+        actualheader = next(lines).strip()
+    except StopIteration:
+        actualheader = ''
+    if actualheader != header:
+        raise ValueError(f'bad header {actualheader!r}')
+
+    for row in _get_reader(lines, delimiter='\t'):
+        yield tuple(v.strip() for v in row)
+
+
+def write_tsv(outfile, header, rows, *,
+             _open=open,
+             _get_writer=csv.writer,
+             ):
+    """Write each of the rows to the given TSV (tab-separated) file."""
+    if isinstance(outfile, str):
+        with _open(outfile, 'w', newline='') as outfile:
+            return write_tsv(outfile, header, rows,
+                            _open=_open,
+                            _get_writer=_get_writer,
+                            )
+
+    if isinstance(header, str):
+        header = header.split('\t')
+    writer = _get_writer(outfile, delimiter='\t')
+    writer.writerow(header)
+    for row in rows:
+        writer.writerow('' if v is None else str(v)
+                        for v in row)
+
+
+class Slot:
+    """A descriptor that provides a slot.
+
+    This is useful for types that can't have slots via __slots__,
+    e.g. tuple subclasses.
+    """
+
+    __slots__ = ('initial', 'default', 'readonly', 'instances', 'name')
+
+    def __init__(self, initial=_NOT_SET, *,
+                 default=_NOT_SET,
+                 readonly=False,
+                 ):
+        self.initial = initial
+        self.default = default
+        self.readonly = readonly
+
+        # The instance cache is not inherently tied to the normal
+        # lifetime of the instances.  So must do something in order to
+        # avoid keeping the instances alive by holding a reference here.
+        # Ideally we would use weakref.WeakValueDictionary to do this.
+        # However, most builtin types do not support weakrefs.  So
+        # instead we monkey-patch __del__ on the attached class to clear
+        # the instance.
+        self.instances = {}
+        self.name = None
+
+    def __set_name__(self, cls, name):
+        if self.name is not None:
+            raise TypeError('already used')
+        self.name = name
+        try:
+            slotnames = cls.__slot_names__
+        except AttributeError:
+            slotnames = cls.__slot_names__ = []
+        slotnames.append(name)
+        self._ensure___del__(cls, slotnames)
+
+    def __get__(self, obj, cls):
+        if obj is None:  # called on the class
+            return self
+        try:
+            value = self.instances[id(obj)]
+        except KeyError:
+            if self.initial is _NOT_SET:
+                value = self.default
+            else:
+                value = self.initial
+            self.instances[id(obj)] = value
+        if value is _NOT_SET:
+            raise AttributeError(self.name)
+        # XXX Optionally make a copy?
+        return value
+
+    def __set__(self, obj, value):
+        if self.readonly:
+            raise AttributeError(f'{self.name} is readonly')
+        # XXX Optionally coerce?
+        self.instances[id(obj)] = value
+
+    def __delete__(self, obj):
+        if self.readonly:
+            raise AttributeError(f'{self.name} is readonly')
+        self.instances[id(obj)] = self.default  # XXX refleak?
+
+    def _ensure___del__(self, cls, slotnames):  # See the comment in __init__().
+        try:
+            old___del__ = cls.__del__
+        except AttributeError:
+            old___del__ = (lambda s: None)
+        else:
+            if getattr(old___del__, '_slotted', False):
+                return
+
+        def __del__(_self):
+            for name in slotnames:
+                delattr(_self, name)
+            old___del__(_self)
+        __del__._slotted = True
+        cls.__del__ = __del__
+
+    def set(self, obj, value):
+        """Update the cached value for an object.
+
+        This works even if the descriptor is read-only.  This is
+        particularly useful when initializing the object (e.g. in
+        its __new__ or __init__).
+        """
+        self.instances[id(obj)] = value
+
+
+class classonly:
+    """A non-data descriptor that makes a value only visible on the class.
+
+    This is like the "classmethod" builtin, but does not show up on
+    instances of the class.  It may be used as a decorator.
+    """
+
+    def __init__(self, value):
+        self.value = value
+        self.getter = classmethod(value).__get__
+        self.name = None
+
+    def __set_name__(self, cls, name):
+        if self.name is not None:
+            raise TypeError('already used')
+        self.name = name
+
+    def __get__(self, obj, cls):
+        if obj is not None:
+            raise AttributeError(self.name)
+        # called on the class
+        return self.getter(None, cls)
+
+
+class _NTBase:
+
+    __slots__ = ()
+
+    @classonly
+    def from_raw(cls, raw):
+        if not raw:
+            return None
+        elif isinstance(raw, cls):
+            return raw
+        elif isinstance(raw, str):
+            return cls.from_string(raw)
+        else:
+            if hasattr(raw, 'items'):
+                return cls(**raw)
+            try:
+                args = tuple(raw)
+            except TypeError:
+                pass
+            else:
+                return cls(*args)
+        raise NotImplementedError
+
+    @classonly
+    def from_string(cls, value):
+        """Return a new instance based on the given string."""
+        raise NotImplementedError
+
+    @classmethod
+    def _make(cls, iterable):  # The default _make() is not subclass-friendly.
+        return cls.__new__(cls, *iterable)
+
+    # XXX Always validate?
+    #def __init__(self, *args, **kwargs):
+    #    self.validate()
+
+    # XXX The default __repr__() is not subclass-friendly (where the name changes).
+    #def __repr__(self):
+    #    _, _, sig = super().__repr__().partition('(')
+    #    return f'{self.__class__.__name__}({sig}'
+
+    # To make sorting work with None:
+    def __lt__(self, other):
+        try:
+            return super().__lt__(other)
+        except TypeError:
+            if None in self:
+                return True
+            elif None in other:
+                return False
+            else:
+                raise
+
+    def validate(self):
+        return
+
+    # XXX Always validate?
+    #def _replace(self, **kwargs):
+    #    obj = super()._replace(**kwargs)
+    #    obj.validate()
+    #    return obj