_project.py, _loader/loadcontext.py: Added Project.loaded_projects()

This adds a new _ProjectInformation type to types.py which
is returned by the new Project.loaded_projects() API, supported
by a new internal LoaderContext.loaded_projects() function.

This allows the frontend some helpful information to print about
the loaded projects in the session heading.

3 files changed, 62 insertions, 0 deletions

diff --git a/src/buildstream/_loader/loadcontext.py b/src/buildstream/_loader/loadcontext.py
index 6183a192b..4e6c9bca6 100644
--- a/src/buildstream/_loader/loadcontext.py
+++ b/src/buildstream/_loader/loadcontext.py
@@ -19,6 +19,7 @@
 
 from .._exceptions import LoadError
 from ..exceptions import LoadErrorReason
+from ..types import _ProjectInformation
 
 
 # ProjectLoaders()
@@ -74,6 +75,21 @@ class ProjectLoaders:
         elif primary and duplicates:
             self._raise_conflict(duplicates, internal)
 
+    # loaded_projects()
+    #
+    # A generator which yeilds all of the instances
+    # of this loaded project.
+    #
+    # Yields:
+    #    (_ProjectInformation): A descriptive project information object
+    #
+    def loaded_projects(self):
+        for loader in self._collect:
+            duplicating, internalizing = self._search_project_relationships(loader)
+            yield _ProjectInformation(
+                loader.project, loader.provenance, [str(l) for l in duplicating], [str(l) for l in internalizing]
+            )
+
     # _search_project_relationships()
     #
     # Searches this loader's ancestry for projects which mark this
@@ -241,3 +257,14 @@ class LoadContext:
             self._loaders[project.name] = project_loaders
 
         project_loaders.register_loader(loader)
+
+    # loaded_projects()
+    #
+    # A generator which yeilds all of the loaded projects
+    #
+    # Yields:
+    #    (_ProjectInformation): A descriptive project information object
+    #
+    def loaded_projects(self):
+        for _, project_loaders in self._loaders.items():
+            yield from project_loaders.loaded_projects()
diff --git a/src/buildstream/_project.py b/src/buildstream/_project.py
index 3180165bd..3562ea5d4 100644
--- a/src/buildstream/_project.py
+++ b/src/buildstream/_project.py
@@ -622,6 +622,23 @@ class Project:
 
         return False
 
+    # loaded_projects()
+    #
+    # A generator which yields all the projects in context of a loaded
+    # pipeline, including the self project.
+    #
+    # Projects will be yielded in the order in which they were loaded
+    # for the current session's pipeline.
+    #
+    # This is used by the frontend to print information about all the
+    # loaded projects.
+    #
+    # Yields:
+    #    (_ProjectInformation): A descriptive project information object
+    #
+    def loaded_projects(self):
+        yield from self.load_context.loaded_projects()
+
     ########################################################
     #                    Private Methods                   #
     ########################################################
diff --git a/src/buildstream/types.py b/src/buildstream/types.py
index 3d97fc7b9..cf76defbd 100644
--- a/src/buildstream/types.py
+++ b/src/buildstream/types.py
@@ -226,6 +226,24 @@ class _PipelineSelection(FastEnum):
         return str(self.value)
 
 
+# _ProjectInformation()
+#
+# A descriptive object about a project.
+#
+# Args:
+#    project (Project): The project instance
+#    provenance (ProvenanceInformation): The provenance information, if any
+#    duplicates (list): List of project descriptions which declared this project as a duplicate
+#    internal (list): List of project descriptions which declared this project as internal
+#
+class _ProjectInformation:
+    def __init__(self, project, provenance, duplicates, internal):
+        self.project = project
+        self.provenance = provenance
+        self.duplicates = duplicates
+        self.internal = internal
+
+
 ########################################
 #           Type aliases               #
 ########################################