6 files changed, 230 insertions, 0 deletions
diff --git a/grc/core/schema_checker/__init__.py b/grc/core/schema_checker/__init__.py
new file mode 100644
index 0000000000..e92500ed4a
--- /dev/null
+++ b/grc/core/schema_checker/__init__.py
@@ -0,0 +1,5 @@
+from .validator import Validator
+
+from .block import BLOCK_SCHEME
+from .domain import DOMAIN_SCHEME
+from .flow_graph import FLOW_GRAPH_SCHEME
diff --git a/grc/core/schema_checker/block.py b/grc/core/schema_checker/block.py
new file mode 100644
index 0000000000..db8830fddf
--- /dev/null
+++ b/grc/core/schema_checker/block.py
@@ -0,0 +1,57 @@
+from .utils import Spec, expand, str_
+
+PARAM_SCHEME = expand(
+    base_key=str_,   # todo: rename/remove
+
+    id=str_,
+    label=str_,
+    category=str_,
+
+    dtype=str_,
+    default=object,
+
+    options=list,
+    option_labels=list,
+    option_attributes=Spec(types=dict, required=False, item_scheme=(str_, list)),
+
+    hide=str_,
+)
+PORT_SCHEME = expand(
+    label=str_,
+    domain=str_,
+
+    id=str_,
+    dtype=str_,
+    vlen=(int, str_),
+
+    multiplicity=(int, str_),
+    optional=(bool, int, str_),
+    hide=(bool, str_),
+)
+TEMPLATES_SCHEME = expand(
+    imports=str_,
+    var_make=str_,
+    make=str_,
+    callbacks=list,
+)
+BLOCK_SCHEME = expand(
+    id=Spec(types=str_, required=True, item_scheme=None),
+    label=str_,
+    category=(list, str_),
+    flags=(list, str_),
+
+    parameters=Spec(types=list, required=False, item_scheme=PARAM_SCHEME),
+    inputs=Spec(types=list, required=False, item_scheme=PORT_SCHEME),
+    outputs=Spec(types=list, required=False, item_scheme=PORT_SCHEME),
+
+    checks=(list, str_),
+    value=str_,
+
+    templates=Spec(types=dict, required=False, item_scheme=TEMPLATES_SCHEME),
+
+    documentation=str_,
+
+    file_format=Spec(types=int, required=True, item_scheme=None),
+
+    block_wrapper_path=str_,  # todo: rename/remove
+)
diff --git a/grc/core/schema_checker/domain.py b/grc/core/schema_checker/domain.py
new file mode 100644
index 0000000000..86c29ed3c6
--- /dev/null
+++ b/grc/core/schema_checker/domain.py
@@ -0,0 +1,16 @@
+from .utils import Spec, expand, str_
+
+DOMAIN_CONNECTION = expand(
+    type=Spec(types=list, required=True, item_scheme=None),
+    connect=str_,
+)
+
+DOMAIN_SCHEME = expand(
+    id=Spec(types=str_, required=True, item_scheme=None),
+    label=str_,
+    color=str_,
+    multiple_connections_per_input=bool,
+    multiple_connections_per_output=bool,
+
+    templates=Spec(types=list, required=False, item_scheme=DOMAIN_CONNECTION)
+)
+\ No newline at end of file
diff --git a/grc/core/schema_checker/flow_graph.py b/grc/core/schema_checker/flow_graph.py
new file mode 100644
index 0000000000..746fbf4aa7
--- /dev/null
+++ b/grc/core/schema_checker/flow_graph.py
@@ -0,0 +1,23 @@
+from .utils import Spec, expand, str_
+
+OPTIONS_SCHEME = expand(
+    parameters=Spec(types=dict, required=False, item_scheme=(str_, str_)),
+    states=Spec(types=dict, required=False, item_scheme=(str_, str_)),
+)
+
+BLOCK_SCHEME = expand(
+    name=str_,
+    id=str_,
+    **OPTIONS_SCHEME
+)
+
+FLOW_GRAPH_SCHEME = expand(
+    options=Spec(types=dict, required=False, item_scheme=OPTIONS_SCHEME),
+    blocks=Spec(types=dict, required=False, item_scheme=BLOCK_SCHEME),
+    connections=list,
+
+    metadata=Spec(types=dict, required=True, item_scheme=expand(
+        file_format=Spec(types=int, required=True, item_scheme=None),
+    ))
+
+)
diff --git a/grc/core/schema_checker/utils.py b/grc/core/schema_checker/utils.py
new file mode 100644
index 0000000000..a9cf4c0175
--- /dev/null
+++ b/grc/core/schema_checker/utils.py
@@ -0,0 +1,27 @@
+import collections
+
+import six
+
+Spec = collections.namedtuple('Spec', 'types required item_scheme')
+
+
+def expand(**kwargs):
+    def expand_spec(spec):
+        if not isinstance(spec, Spec):
+            types_ = spec if isinstance(spec, tuple) else (spec,)
+            spec = Spec(types=types_, required=False, item_scheme=None)
+        elif not isinstance(spec.types, tuple):
+            spec = Spec(types=(spec.types,), required=spec.required,
+                        item_scheme=spec.item_scheme)
+        return spec
+    return {key: expand_spec(value) for key, value in kwargs.items()}
+
+
+str_ = six.string_types
+
+
+class Message(collections.namedtuple('Message', 'path type message')):
+    fmt = '{path}: {type}: {message}'
+
+    def __str__(self):
+        return self.fmt.format(**self._asdict())
diff --git a/grc/core/schema_checker/validator.py b/grc/core/schema_checker/validator.py
new file mode 100644
index 0000000000..ab4d43bc67
--- /dev/null
+++ b/grc/core/schema_checker/validator.py
@@ -0,0 +1,102 @@
+# Copyright 2016 Free Software Foundation, Inc.
+# This file is part of GNU Radio
+#
+# GNU Radio Companion is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2 of the License, or (at your
+# option) any later version.
+#
+# GNU Radio Companion is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+
+from __future__ import print_function
+
+import six
+
+from .utils import Message, Spec
+
+
+class Validator(object):
+
+    def __init__(self, scheme=None):
+        self._path = []
+        self.scheme = scheme
+        self.messages = []
+        self.passed = False
+
+    def run(self, data):
+        if not self.scheme:
+            return True
+        self._reset()
+        self._path.append('block')
+        self._check(data, self.scheme)
+        self._path.pop()
+        return self.passed
+
+    def _reset(self):
+        del self.messages[:]
+        del self._path[:]
+        self.passed = True
+
+    def _check(self, data, scheme):
+        if not data or not isinstance(data, dict):
+            self._error('Empty data or not a dict')
+            return
+        if isinstance(scheme, dict):
+            self._check_dict(data, scheme)
+        else:
+            self._check_var_key_dict(data, *scheme)
+
+    def _check_var_key_dict(self, data, key_type, value_scheme):
+        for key, value in six.iteritems(data):
+            if not isinstance(key, key_type):
+                self._error('Key type {!r} for {!r} not in valid types'.format(
+                    type(value).__name__, key))
+            if isinstance(value_scheme, Spec):
+                self._check_dict(value, value_scheme)
+            elif not isinstance(value, value_scheme):
+                self._error('Value type {!r} for {!r} not in valid types'.format(
+                    type(value).__name__, key))
+
+    def _check_dict(self, data, scheme):
+        for key, (types_, required, item_scheme) in six.iteritems(scheme):
+            try:
+                value = data[key]
+            except KeyError:
+                if required:
+                    self._error('Missing required entry {!r}'.format(key))
+                continue
+
+            self._check_value(value, types_, item_scheme, label=key)
+
+        for key in set(data).difference(scheme):
+            self._warn('Ignoring extra key {!r}'.format(key))
+
+    def _check_list(self, data, scheme, label):
+        for i, item in enumerate(data):
+            self._path.append('{}[{}]'.format(label, i))
+            self._check(item, scheme)
+            self._path.pop()
+
+    def _check_value(self, value, types_, item_scheme, label):
+        if not isinstance(value, types_):
+            self._error('Value type {!r} for {!r} not in valid types'.format(
+                type(value).__name__, label))
+        if item_scheme:
+            if isinstance(value, list):
+                self._check_list(value, item_scheme, label)
+            elif isinstance(value, dict):
+                self._check(value, item_scheme)
+
+    def _error(self, msg):
+        self.messages.append(Message('.'.join(self._path), 'error', msg))
+        self.passed = False
+
+    def _warn(self, msg):
+        self.messages.append(Message('.'.join(self._path), 'warn', msg))