interpreter: Split base objects and helpers from interpreterbase.py

4 files changed, 237 insertions, 177 deletions

diff --git a/mesonbuild/interpreterbase/__init__.py b/mesonbuild/interpreterbase/__init__.py
index d635dfd..0d9c4ed 100644
--- a/mesonbuild/interpreterbase/__init__.py
+++ b/mesonbuild/interpreterbase/__init__.py
@@ -24,8 +24,17 @@ __all__ = [
     'is_arg_disabled',
     'is_disabled',
 
+    'InterpreterException',
+    'InvalidCode',
+    'InvalidArguments',
+    'SubdirDoneRequest',
+    'ContinueRequest',
+    'BreakRequest',
+
     'check_stringlist',
+    'default_resolve_key',
     'flatten',
+
     'noPosargs',
     'builtinMethodNoKwargs',
     'noKwargs',
@@ -43,14 +52,6 @@ __all__ = [
     'FeatureDeprecatedKwargs',
 
     'InterpreterBase',
-    'default_resolve_key',
-
-    'InterpreterException',
-    'InvalidCode',
-    'InvalidArguments',
-    'SubdirDoneRequest',
-    'ContinueRequest',
-    'BreakRequest',
 
     'TV_fw_var',
     'TV_fw_args',
@@ -63,6 +64,23 @@ __all__ = [
     'TYPE_key_resolver',
 ]
 
+from .baseobjects import (
+    InterpreterObject,
+    ObjectHolder,
+    RangeHolder,
+    MutableInterpreterObject,
+
+    TV_fw_var,
+    TV_fw_args,
+    TV_fw_kwargs,
+    TV_func,
+    TYPE_elementary,
+    TYPE_var,
+    TYPE_nvar,
+    TYPE_nkwargs,
+    TYPE_key_resolver,
+)
+
 from .exceptions import (
     InterpreterException,
     InvalidCode,
@@ -72,20 +90,16 @@ from .exceptions import (
     BreakRequest,
 )
 
+from .helpers import check_stringlist, default_resolve_key, flatten
+
 from .interpreterbase import (
-    InterpreterObject,
-    ObjectHolder,
-    RangeHolder,
     MesonVersionString,
-    MutableInterpreterObject,
 
     Disabler,
     is_disabler,
     is_arg_disabled,
     is_disabled,
 
-    check_stringlist,
-    flatten,
     noPosargs,
     builtinMethodNoKwargs,
     noKwargs,
@@ -103,15 +117,4 @@ from .interpreterbase import (
     FeatureDeprecatedKwargs,
 
     InterpreterBase,
-    default_resolve_key,
-
-    TV_fw_var,
-    TV_fw_args,
-    TV_fw_kwargs,
-    TV_func,
-    TYPE_elementary,
-    TYPE_var,
-    TYPE_nvar,
-    TYPE_nkwargs,
-    TYPE_key_resolver,
 )
diff --git a/mesonbuild/interpreterbase/baseobjects.py b/mesonbuild/interpreterbase/baseobjects.py
new file mode 100644
index 0000000..f48ab9b
--- /dev/null
+++ b/mesonbuild/interpreterbase/baseobjects.py
@@ -0,0 +1,79 @@
+# Copyright 2013-2021 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .. import mparser
+from .exceptions import InvalidCode
+from .helpers import flatten
+
+import typing as T
+
+TV_fw_var = T.Union[str, int, float, bool, list, dict, 'InterpreterObject', 'ObjectHolder']
+TV_fw_args = T.List[T.Union[mparser.BaseNode, TV_fw_var]]
+TV_fw_kwargs = T.Dict[str, T.Union[mparser.BaseNode, TV_fw_var]]
+
+TV_func = T.TypeVar('TV_func', bound=T.Callable[..., T.Any])
+
+TYPE_elementary = T.Union[str, int, float, bool]
+TYPE_var = T.Union[TYPE_elementary, T.List[T.Any], T.Dict[str, T.Any], 'InterpreterObject', 'ObjectHolder']
+TYPE_nvar = T.Union[TYPE_var, mparser.BaseNode]
+TYPE_nkwargs = T.Dict[str, TYPE_nvar]
+TYPE_key_resolver = T.Callable[[mparser.BaseNode], str]
+
+class InterpreterObject:
+    def __init__(self) -> None:
+        self.methods = {}  # type: T.Dict[str, T.Callable[[T.List[TYPE_nvar], TYPE_nkwargs], TYPE_var]]
+        # Current node set during a method call. This can be used as location
+        # when printing a warning message during a method call.
+        self.current_node = None  # type: mparser.BaseNode
+
+    def method_call(
+                self,
+                method_name: str,
+                args: TV_fw_args,
+                kwargs: TV_fw_kwargs
+            ) -> TYPE_var:
+        if method_name in self.methods:
+            method = self.methods[method_name]
+            if not getattr(method, 'no-args-flattening', False):
+                args = flatten(args)
+            return method(args, kwargs)
+        raise InvalidCode('Unknown method "%s" in object.' % method_name)
+
+class MutableInterpreterObject(InterpreterObject):
+    def __init__(self) -> None:
+        super().__init__()
+
+TV_InterpreterObject = T.TypeVar('TV_InterpreterObject')
+
+class ObjectHolder(T.Generic[TV_InterpreterObject]):
+    def __init__(self, obj: TV_InterpreterObject, subproject: str = '') -> None:
+        self.held_object = obj
+        self.subproject = subproject
+
+    def __repr__(self) -> str:
+        return f'<Holder: {self.held_object!r}>'
+
+class RangeHolder(InterpreterObject):
+    def __init__(self, start: int, stop: int, step: int) -> None:
+        super().__init__()
+        self.range = range(start, stop, step)
+
+    def __iter__(self) -> T.Iterator[int]:
+        return iter(self.range)
+
+    def __getitem__(self, key: int) -> int:
+        return self.range[key]
+
+    def __len__(self) -> int:
+        return len(self.range)
diff --git a/mesonbuild/interpreterbase/helpers.py b/mesonbuild/interpreterbase/helpers.py
new file mode 100644
index 0000000..1070a9e
--- /dev/null
+++ b/mesonbuild/interpreterbase/helpers.py
@@ -0,0 +1,107 @@
+# Copyright 2013-2021 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from .. import mparser, mlog
+from .exceptions import InvalidArguments, InterpreterException
+
+import collections.abc
+import typing as T
+
+if T.TYPE_CHECKING:
+    from .baseobjects import TYPE_nvar, TV_fw_args, TV_fw_kwargs
+
+def flatten(args: T.Union['TYPE_nvar', T.List['TYPE_nvar']]) -> T.List['TYPE_nvar']:
+    if isinstance(args, mparser.StringNode):
+        assert isinstance(args.value, str)
+        return [args.value]
+    if not isinstance(args, collections.abc.Sequence):
+        return [args]
+    result: T.List['TYPE_nvar'] = []
+    for a in args:
+        if isinstance(a, list):
+            rest = flatten(a)
+            result = result + rest
+        elif isinstance(a, mparser.StringNode):
+            result.append(a.value)
+        else:
+            result.append(a)
+    return result
+
+def check_stringlist(a: T.Any, msg: str = 'Arguments must be strings.') -> None:
+    if not isinstance(a, list):
+        mlog.debug('Not a list:', str(a))
+        raise InvalidArguments('Argument not a list.')
+    if not all(isinstance(s, str) for s in a):
+        mlog.debug('Element not a string:', str(a))
+        raise InvalidArguments(msg)
+
+def default_resolve_key(key: mparser.BaseNode) -> str:
+    if not isinstance(key, mparser.IdNode):
+        raise InterpreterException('Invalid kwargs format.')
+    return key.value
+
+def get_callee_args(wrapped_args: T.Sequence[T.Any], want_subproject: bool = False) -> T.Tuple[T.Any, mparser.BaseNode, 'TV_fw_args', 'TV_fw_kwargs', T.Optional[str]]:
+    s = wrapped_args[0]
+    n = len(wrapped_args)
+    # Raise an error if the codepaths are not there
+    subproject = None  # type: T.Optional[str]
+    if want_subproject and n == 2:
+        if hasattr(s, 'subproject'):
+            # Interpreter base types have 2 args: self, node
+            node = wrapped_args[1]
+            # args and kwargs are inside the node
+            args = None
+            kwargs = None
+            subproject = s.subproject
+        elif hasattr(wrapped_args[1], 'subproject'):
+            # Module objects have 2 args: self, interpreter
+            node = wrapped_args[1].current_node
+            # args and kwargs are inside the node
+            args = None
+            kwargs = None
+            subproject = wrapped_args[1].subproject
+        else:
+            raise AssertionError(f'Unknown args: {wrapped_args!r}')
+    elif n == 3:
+        # Methods on objects (*Holder, MesonMain, etc) have 3 args: self, args, kwargs
+        node = s.current_node
+        args = wrapped_args[1]
+        kwargs = wrapped_args[2]
+        if want_subproject:
+            if hasattr(s, 'subproject'):
+                subproject = s.subproject
+            elif hasattr(s, 'interpreter'):
+                subproject = s.interpreter.subproject
+    elif n == 4:
+        # Meson functions have 4 args: self, node, args, kwargs
+        # Module functions have 4 args: self, state, args, kwargs
+        from .interpreterbase import InterpreterBase  # TODO: refactor to avoid this import
+        if isinstance(s, InterpreterBase):
+            node = wrapped_args[1]
+        else:
+            node = wrapped_args[1].current_node
+        args = wrapped_args[2]
+        kwargs = wrapped_args[3]
+        if want_subproject:
+            if isinstance(s, InterpreterBase):
+                subproject = s.subproject
+            else:
+                subproject = wrapped_args[1].subproject
+    else:
+        raise AssertionError(f'Unknown args: {wrapped_args!r}')
+    # Sometimes interpreter methods are called internally with None instead of
+    # empty list/dict
+    args = args if args is not None else []
+    kwargs = kwargs if kwargs is not None else {}
+    return s, node, args, kwargs, subproject
diff --git a/mesonbuild/interpreterbase/interpreterbase.py b/mesonbuild/interpreterbase/interpreterbase.py
index 708741a..8c28b78 100644
--- a/mesonbuild/interpreterbase/interpreterbase.py
+++ b/mesonbuild/interpreterbase/interpreterbase.py
@@ -18,6 +18,18 @@
 from .. import mparser, mesonlib, mlog
 from .. import environment, dependencies
 
+from .baseobjects import (
+    InterpreterObject,
+    MutableInterpreterObject,
+    ObjectHolder,
+    RangeHolder,
+
+    TV_func,
+    TYPE_var,
+    TYPE_nvar,
+    TYPE_nkwargs,
+)
+
 from .exceptions import (
     InterpreterException,
     InvalidCode,
@@ -27,157 +39,25 @@ from .exceptions import (
     BreakRequest
 )
 
+from .helpers import check_stringlist, default_resolve_key, flatten, get_callee_args
+
 from functools import wraps
 import abc
-import collections.abc
 import itertools
 import os, copy, re
 import typing as T
 
-TV_fw_var = T.Union[str, int, float, bool, list, dict, 'InterpreterObject', 'ObjectHolder']
-TV_fw_args = T.List[T.Union[mparser.BaseNode, TV_fw_var]]
-TV_fw_kwargs = T.Dict[str, T.Union[mparser.BaseNode, TV_fw_var]]
-
-TV_func = T.TypeVar('TV_func', bound=T.Callable[..., T.Any])
-
-TYPE_elementary = T.Union[str, int, float, bool]
-TYPE_var = T.Union[TYPE_elementary, T.List[T.Any], T.Dict[str, T.Any], 'InterpreterObject', 'ObjectHolder']
-TYPE_nvar = T.Union[TYPE_var, mparser.BaseNode]
-TYPE_nkwargs = T.Dict[str, TYPE_nvar]
-TYPE_key_resolver = T.Callable[[mparser.BaseNode], str]
-
-class InterpreterObject:
-    def __init__(self) -> None:
-        self.methods = {}  # type: T.Dict[str, T.Callable[[T.List[TYPE_nvar], TYPE_nkwargs], TYPE_var]]
-        # Current node set during a method call. This can be used as location
-        # when printing a warning message during a method call.
-        self.current_node = None  # type: mparser.BaseNode
-
-    def method_call(
-                self,
-                method_name: str,
-                args: TV_fw_args,
-                kwargs: TV_fw_kwargs
-            ) -> TYPE_var:
-        if method_name in self.methods:
-            method = self.methods[method_name]
-            if not getattr(method, 'no-args-flattening', False):
-                args = flatten(args)
-            return method(args, kwargs)
-        raise InvalidCode('Unknown method "%s" in object.' % method_name)
-
-TV_InterpreterObject = T.TypeVar('TV_InterpreterObject')
-
-class ObjectHolder(T.Generic[TV_InterpreterObject]):
-    def __init__(self, obj: TV_InterpreterObject, subproject: str = '') -> None:
-        self.held_object = obj
-        self.subproject = subproject
-
-    def __repr__(self) -> str:
-        return f'<Holder: {self.held_object!r}>'
 
 class MesonVersionString(str):
     pass
 
-class RangeHolder(InterpreterObject):
-    def __init__(self, start: int, stop: int, step: int) -> None:
-        super().__init__()
-        self.range = range(start, stop, step)
-
-    def __iter__(self) -> T.Iterator[int]:
-        return iter(self.range)
-
-    def __getitem__(self, key: int) -> int:
-        return self.range[key]
-
-    def __len__(self) -> int:
-        return len(self.range)
 
 # Decorators for method calls.
 
-def check_stringlist(a: T.Any, msg: str = 'Arguments must be strings.') -> None:
-    if not isinstance(a, list):
-        mlog.debug('Not a list:', str(a))
-        raise InvalidArguments('Argument not a list.')
-    if not all(isinstance(s, str) for s in a):
-        mlog.debug('Element not a string:', str(a))
-        raise InvalidArguments(msg)
-
-def _get_callee_args(wrapped_args: T.Sequence[T.Any], want_subproject: bool = False) -> T.Tuple[T.Any, mparser.BaseNode, TV_fw_args, TV_fw_kwargs, T.Optional[str]]:
-    s = wrapped_args[0]
-    n = len(wrapped_args)
-    # Raise an error if the codepaths are not there
-    subproject = None  # type: T.Optional[str]
-    if want_subproject and n == 2:
-        if hasattr(s, 'subproject'):
-            # Interpreter base types have 2 args: self, node
-            node = wrapped_args[1]
-            # args and kwargs are inside the node
-            args = None
-            kwargs = None
-            subproject = s.subproject
-        elif hasattr(wrapped_args[1], 'subproject'):
-            # Module objects have 2 args: self, interpreter
-            node = wrapped_args[1].current_node
-            # args and kwargs are inside the node
-            args = None
-            kwargs = None
-            subproject = wrapped_args[1].subproject
-        else:
-            raise AssertionError(f'Unknown args: {wrapped_args!r}')
-    elif n == 3:
-        # Methods on objects (*Holder, MesonMain, etc) have 3 args: self, args, kwargs
-        node = s.current_node
-        args = wrapped_args[1]
-        kwargs = wrapped_args[2]
-        if want_subproject:
-            if hasattr(s, 'subproject'):
-                subproject = s.subproject
-            elif hasattr(s, 'interpreter'):
-                subproject = s.interpreter.subproject
-    elif n == 4:
-        # Meson functions have 4 args: self, node, args, kwargs
-        # Module functions have 4 args: self, state, args, kwargs
-        if isinstance(s, InterpreterBase):
-            node = wrapped_args[1]
-        else:
-            node = wrapped_args[1].current_node
-        args = wrapped_args[2]
-        kwargs = wrapped_args[3]
-        if want_subproject:
-            if isinstance(s, InterpreterBase):
-                subproject = s.subproject
-            else:
-                subproject = wrapped_args[1].subproject
-    else:
-        raise AssertionError(f'Unknown args: {wrapped_args!r}')
-    # Sometimes interpreter methods are called internally with None instead of
-    # empty list/dict
-    args = args if args is not None else []
-    kwargs = kwargs if kwargs is not None else {}
-    return s, node, args, kwargs, subproject
-
-def flatten(args: T.Union[TYPE_nvar, T.List[TYPE_nvar]]) -> T.List[TYPE_nvar]:
-    if isinstance(args, mparser.StringNode):
-        assert isinstance(args.value, str)
-        return [args.value]
-    if not isinstance(args, collections.abc.Sequence):
-        return [args]
-    result = []  # type: T.List[TYPE_nvar]
-    for a in args:
-        if isinstance(a, list):
-            rest = flatten(a)
-            result = result + rest
-        elif isinstance(a, mparser.StringNode):
-            result.append(a.value)
-        else:
-            result.append(a)
-    return result
-
 def noPosargs(f: TV_func) -> TV_func:
     @wraps(f)
     def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        args = _get_callee_args(wrapped_args)[2]
+        args = get_callee_args(wrapped_args)[2]
         if args:
             raise InvalidArguments('Function does not take positional arguments.')
         return f(*wrapped_args, **wrapped_kwargs)
@@ -199,7 +79,7 @@ def builtinMethodNoKwargs(f: TV_func) -> TV_func:
 def noKwargs(f: TV_func) -> TV_func:
     @wraps(f)
     def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        kwargs = _get_callee_args(wrapped_args)[3]
+        kwargs = get_callee_args(wrapped_args)[3]
         if kwargs:
             raise InvalidArguments('Function does not take keyword arguments.')
         return f(*wrapped_args, **wrapped_kwargs)
@@ -208,7 +88,7 @@ def noKwargs(f: TV_func) -> TV_func:
 def stringArgs(f: TV_func) -> TV_func:
     @wraps(f)
     def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        args = _get_callee_args(wrapped_args)[2]
+        args = get_callee_args(wrapped_args)[2]
         assert(isinstance(args, list))
         check_stringlist(args)
         return f(*wrapped_args, **wrapped_kwargs)
@@ -221,7 +101,7 @@ def noArgsFlattening(f: TV_func) -> TV_func:
 def disablerIfNotFound(f: TV_func) -> TV_func:
     @wraps(f)
     def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-        kwargs = _get_callee_args(wrapped_args)[3]
+        kwargs = get_callee_args(wrapped_args)[3]
         disabler = kwargs.pop('disabler', False)
         ret = f(*wrapped_args, **wrapped_kwargs)
         if disabler and not ret.held_object.found():
@@ -237,7 +117,7 @@ class permittedKwargs:
     def __call__(self, f: TV_func) -> TV_func:
         @wraps(f)
         def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            s, node, args, kwargs, _ = _get_callee_args(wrapped_args)
+            s, node, args, kwargs, _ = get_callee_args(wrapped_args)
             for k in kwargs:
                 if k not in self.permitted:
                     mlog.warning(f'''Passed invalid keyword argument "{k}".''', location=node)
@@ -298,7 +178,7 @@ def typed_pos_args(name: str, *types: T.Union[T.Type, T.Tuple[T.Type, ...]],
 
         @wraps(f)
         def wrapper(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            args = _get_callee_args(wrapped_args)[2]
+            args = get_callee_args(wrapped_args)[2]
 
             # These are implementation programming errors, end users should never see them.
             assert isinstance(args, list), args
@@ -480,7 +360,7 @@ def typed_kwargs(name: str, *types: KwargInfo) -> T.Callable[..., T.Any]:
 
         @wraps(f)
         def wrapper(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            kwargs, subproject = _get_callee_args(wrapped_args, want_subproject=True)[3:5]
+            kwargs, subproject = get_callee_args(wrapped_args, want_subproject=True)[3:5]
 
             all_names = {t.name for t in types}
             unknowns = set(kwargs).difference(all_names)
@@ -606,7 +486,7 @@ class FeatureCheckBase(metaclass=abc.ABCMeta):
     def __call__(self, f: TV_func) -> TV_func:
         @wraps(f)
         def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            subproject = _get_callee_args(wrapped_args, want_subproject=True)[4]
+            subproject = get_callee_args(wrapped_args, want_subproject=True)[4]
             if subproject is None:
                 raise AssertionError(f'{wrapped_args!r}')
             self.use(subproject)
@@ -693,7 +573,7 @@ class FeatureCheckKwargsBase(metaclass=abc.ABCMeta):
     def __call__(self, f: TV_func) -> TV_func:
         @wraps(f)
         def wrapped(*wrapped_args: T.Any, **wrapped_kwargs: T.Any) -> T.Any:
-            kwargs, subproject = _get_callee_args(wrapped_args, want_subproject=True)[3:5]
+            kwargs, subproject = get_callee_args(wrapped_args, want_subproject=True)[3:5]
             if subproject is None:
                 raise AssertionError(f'{wrapped_args!r}')
             for arg in self.kwargs:
@@ -712,10 +592,6 @@ class FeatureDeprecatedKwargs(FeatureCheckKwargsBase):
     feature_check_class = FeatureDeprecated
 
 
-class MutableInterpreterObject(InterpreterObject):
-    def __init__(self) -> None:
-        super().__init__()
-
 class Disabler(InterpreterObject):
     def __init__(self) -> None:
         super().__init__()
@@ -745,11 +621,6 @@ def is_disabled(args: T.Sequence[T.Any], kwargs: T.Dict[str, T.Any]) -> bool:
             return True
     return False
 
-def default_resolve_key(key: mparser.BaseNode) -> str:
-    if not isinstance(key, mparser.IdNode):
-        raise InterpreterException('Invalid kwargs format.')
-    return key.value
-
 class InterpreterBase:
     elementary_types = (int, float, str, bool, list)