Move source from 'buildstream' to 'src/buildstream'

This was discussed in #1008.

Fixes #1009.

1 files changed, 177 insertions, 0 deletions

diff --git a/src/buildstream/types.py b/src/buildstream/types.py
new file mode 100644
index 000000000..d54bf0b6e
--- /dev/null
+++ b/src/buildstream/types.py
@@ -0,0 +1,177 @@
+#
+#  Copyright (C) 2018 Bloomberg LP
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU Lesser General Public
+#  License as published by the Free Software Foundation; either
+#  version 2 of the License, or (at your option) any later version.
+#
+#  This library 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
+#  Lesser General Public License for more details.
+#
+#  You should have received a copy of the GNU Lesser General Public
+#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
+#
+#  Authors:
+#        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>
+#        Jim MacArthur <jim.macarthur@codethink.co.uk>
+#        Benjamin Schubert <bschubert15@bloomberg.net>
+
+"""
+Foundation types
+================
+
+"""
+
+from enum import Enum
+import heapq
+
+
+class Scope(Enum):
+    """Defines the scope of dependencies to include for a given element
+    when iterating over the dependency graph in APIs like
+    :func:`Element.dependencies() <buildstream.element.Element.dependencies>`
+    """
+
+    ALL = 1
+    """All elements which the given element depends on, following
+    all elements required for building. Including the element itself.
+    """
+
+    BUILD = 2
+    """All elements required for building the element, including their
+    respective run dependencies. Not including the given element itself.
+    """
+
+    RUN = 3
+    """All elements required for running the element. Including the element
+    itself.
+    """
+
+    NONE = 4
+    """Just the element itself, no dependencies.
+
+    *Since: 1.4*
+    """
+
+
+class Consistency():
+    """Defines the various consistency states of a :class:`.Source`.
+    """
+
+    INCONSISTENT = 0
+    """Inconsistent
+
+    Inconsistent sources have no explicit reference set. They cannot
+    produce a cache key, be fetched or staged. They can only be tracked.
+    """
+
+    RESOLVED = 1
+    """Resolved
+
+    Resolved sources have a reference and can produce a cache key and
+    be fetched, however they cannot be staged.
+    """
+
+    CACHED = 2
+    """Cached
+
+    Sources have a cached unstaged copy in the source directory.
+    """
+
+
+class CoreWarnings():
+    """CoreWarnings()
+
+    Some common warnings which are raised by core functionalities within BuildStream are found in this class.
+    """
+
+    OVERLAPS = "overlaps"
+    """
+    This warning will be produced when buildstream detects an overlap on an element
+        which is not whitelisted. See :ref:`Overlap Whitelist <public_overlap_whitelist>`
+    """
+
+    REF_NOT_IN_TRACK = "ref-not-in-track"
+    """
+    This warning will be produced when a source is configured with a reference
+    which is found to be invalid based on the configured track
+    """
+
+    BAD_ELEMENT_SUFFIX = "bad-element-suffix"
+    """
+    This warning will be produced when an element whose name does not end in .bst
+    is referenced either on the command line or by another element
+    """
+
+    BAD_CHARACTERS_IN_NAME = "bad-characters-in-name"
+    """
+    This warning will be produces when filename for a target contains invalid
+    characters in its name.
+    """
+
+
+# _KeyStrength():
+#
+# Strength of cache key
+#
+class _KeyStrength(Enum):
+
+    # Includes strong cache keys of all build dependencies and their
+    # runtime dependencies.
+    STRONG = 1
+
+    # Includes names of direct build dependencies but does not include
+    # cache keys of dependencies.
+    WEAK = 2
+
+
+# _UniquePriorityQueue():
+#
+# Implements a priority queue that adds only each key once.
+#
+# The queue will store and priority based on a tuple (key, item).
+#
+class _UniquePriorityQueue:
+
+    def __init__(self):
+        self._items = set()
+        self._heap = []
+
+    # push():
+    #
+    # Push a new item in the queue.
+    #
+    # If the item is already present in the queue as identified by the key,
+    # this is a noop.
+    #
+    # Args:
+    #     key (hashable, comparable): unique key to use for checking for
+    #                                 the object's existence and used for
+    #                                 ordering
+    #     item (any): item to push to the queue
+    #
+    def push(self, key, item):
+        if key not in self._items:
+            self._items.add(key)
+            heapq.heappush(self._heap, (key, item))
+
+    # pop():
+    #
+    # Pop the next item from the queue, by priority order.
+    #
+    # Returns:
+    #     (any): the next item
+    #
+    # Throw:
+    #     IndexError: when the list is empty
+    #
+    def pop(self):
+        key, item = heapq.heappop(self._heap)
+        self._items.remove(key)
+        return item
+
+    def __len__(self):
+        return len(self._heap)