Main Workspace Integration

This commit does the main integration of workspaces, which is a design we agreed on during the 2.8 UI workshop (see https://wiki.blender.org/index.php/Dev:2.8/UI/Workshop_Writeup)

Workspaces should generally be stable, I'm not aware of any remaining bugs (or I've forgotten them :) ). If you find any, let me know!
(Exception: mode switching button might get out of sync with actual mode in some cases, would consider that a limitation/ToDo. Needs to be resolved at some point.)

== Main Changes/Features
* Introduces the new Workspaces as data-blocks.
* Allow storing a number of custom workspaces as part of the user configuration. Needs further work to allow adding and deleting individual workspaces.
* Bundle a default workspace configuration with Blender (current screen-layouts converted to workspaces).
* Pressing button to add a workspace spawns a menu to select between "Duplicate Current" and the workspaces from the user configuration. If no workspaces are stored in the user configuration, the default workspaces are listed instead.
* Store screen-layouts (`bScreen`) per workspace.
* Store an active screen-layout per workspace. Changing the workspace will enable this layout.
* Store active mode in workspace. Changing the workspace will also enter the mode of the new workspace. (Note that we still store the active mode in the object, moving this completely to workspaces is a separate project.)
* Store an active render layer per workspace.
* Moved mode switch from 3D View header to Info Editor header.
* Store active scene in window (not directly workspace related, but overlaps quite a bit).
* Removed 'Use Global Scene' User Preference option.
* Compatibility with old files - a new workspace is created for every screen-layout of old files. Old Blender versions should be able to read files saved with workspace support as well.
* Default .blend only contains one workspace ("General").
* Support appending workspaces.

Opening files without UI and commandline rendering should work fine.

Note that the UI is temporary! We plan to introduce a new global topbar
that contains the workspace options and tabs for switching workspaces.

== Technical Notes
* Workspaces are data-blocks.
* Adding and removing `bScreen`s should be done through `ED_workspace_layout` API now.
* A workspace can be active in multiple windows at the same time.
* The mode menu (which is now in the Info Editor header) doesn't display "Grease Pencil Edit" mode anymore since its availability depends on the active editor. Will be fixed by making Grease Pencil an own object type (as planned).
* The button to change the active workspace object mode may get out of sync with the mode of the active object. Will either be resolved by moving mode out of object data, or we'll disable workspace modes again (there's a `#define USE_WORKSPACE_MODE` for that).
* Screen-layouts (`bScreen`) are IDs and thus stored in a main list-base. Had to add a wrapper `WorkSpaceLayout` so we can store them in a list-base within workspaces, too. On the long run we could completely replace `bScreen` by workspace structs.
* `WorkSpace` types use some special compiler trickery to allow marking structs and struct members as private. BKE_workspace API should be used for accessing those.
* Added scene operators `SCENE_OT_`. Was previously done through screen operators.

== BPY API Changes
* Removed `Screen.scene`, added `Window.scene`
* Removed `UserPreferencesView.use_global_scene`
* Added `Context.workspace`, `Window.workspace` and `BlendData.workspaces`
* Added `bpy.types.WorkSpace` containing `screens`, `object_mode` and `render_layer`
* Added Screen.layout_name for the layout name that'll be displayed in the UI (may differ from internal name)

== What's left?
* There are a few open design questions (T50521). We should find the needed answers and implement them.
* Allow adding and removing individual workspaces from workspace configuration (needs UI design).
* Get the override system ready and support overrides per workspace.
* Support custom UI setups as part of workspaces (hidden panels, hidden buttons, customizable toolbars, etc).
* Allow enabling add-ons per workspace.
* Support custom workspace keymaps.
* Remove special exception for workspaces in linking code (so they're always appended, never linked). Depends on a few things, so best to solve later.
* Get the topbar done.
* Workspaces need a proper icon, current one is just a placeholder :)

Reviewed By: campbellbarton, mont29

Tags: #user_interface, #bf_blender_2.8

Maniphest Tasks: T50521

Differential Revision: https://developer.blender.org/D2451

1 files changed, 399 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/workspace.c b/source/blender/blenkernel/intern/workspace.c
new file mode 100644
index 00000000000..8afad317dce
--- /dev/null
+++ b/source/blender/blenkernel/intern/workspace.c
@@ -0,0 +1,399 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program 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.
+ *
+ * This program 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.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/blenkernel/intern/workspace.c
+ *  \ingroup bke
+ */
+
+/* allow accessing private members of DNA_workspace_types.h */
+#define DNA_PRIVATE_WORKSPACE_ALLOW
+
+#include <stdlib.h>
+
+#include "BLI_utildefines.h"
+#include "BLI_string.h"
+#include "BLI_string_utils.h"
+#include "BLI_listbase.h"
+
+#include "BKE_global.h"
+#include "BKE_library.h"
+#include "BKE_main.h"
+#include "BKE_workspace.h"
+
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_workspace_types.h"
+
+#include "MEM_guardedalloc.h"
+
+
+/* -------------------------------------------------------------------- */
+/* Internal utils */
+
+static void workspace_layout_name_set(
+        WorkSpace *workspace, WorkSpaceLayout *layout, const char *new_name)
+{
+	BLI_strncpy(layout->name, new_name, sizeof(layout->name));
+	BLI_uniquename(&workspace->layouts, layout, "Layout", '.', offsetof(WorkSpaceLayout, name), sizeof(layout->name));
+}
+
+/**
+ * This should only be used directly when it is to be expected that there isn't
+ * a layout within \a workspace that wraps \a screen. Usually - especially outside
+ * of BKE_workspace - #BKE_workspace_layout_find should be used!
+ */
+static WorkSpaceLayout *workspace_layout_find_exec(
+        const WorkSpace *workspace, const bScreen *screen)
+{
+	return BLI_findptr(&workspace->layouts, screen, offsetof(WorkSpaceLayout, screen));
+}
+
+static void workspace_relation_add(
+        ListBase *relation_list, void *parent, void *data)
+{
+	WorkSpaceDataRelation *relation = MEM_callocN(sizeof(*relation), __func__);
+	relation->parent = parent;
+	relation->value = data;
+	/* add to head, if we switch back to it soon we find it faster. */
+	BLI_addhead(relation_list, relation);
+}
+static void workspace_relation_remove(
+        ListBase *relation_list, WorkSpaceDataRelation *relation)
+{
+	BLI_remlink(relation_list, relation);
+	MEM_freeN(relation);
+}
+
+static void workspace_relation_ensure_updated(
+        ListBase *relation_list, void *parent, void *data)
+{
+	WorkSpaceDataRelation *relation = BLI_findptr(relation_list, parent, offsetof(WorkSpaceDataRelation, parent));
+	if (relation != NULL) {
+		relation->value = data;
+		/* reinsert at the head of the list, so that more commonly used relations are found faster. */
+		BLI_remlink(relation_list, relation);
+		BLI_addhead(relation_list, relation);
+	}
+	else {
+		/* no matching relation found, add new one */
+		workspace_relation_add(relation_list, parent, data);
+	}
+}
+
+static void *workspace_relation_get_data_matching_parent(
+        const ListBase *relation_list, const void *parent)
+{
+	WorkSpaceDataRelation *relation = BLI_findptr(relation_list, parent, offsetof(WorkSpaceDataRelation, parent));
+	if (relation != NULL) {
+		return relation->value;
+	}
+	else {
+		return NULL;
+	}
+}
+
+/**
+ * Checks if \a screen is already used within any workspace. A screen should never be assigned to multiple
+ * WorkSpaceLayouts, but that should be ensured outside of the BKE_workspace module and without such checks.
+ * Hence, this should only be used as assert check before assigining a screen to a workspace.
+ */
+#ifndef NDEBUG
+static bool workspaces_is_screen_used(
+#else
+static bool UNUSED_FUNCTION(workspaces_is_screen_used)(
+#endif
+        const Main *bmain, bScreen *screen)
+{
+	for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
+		if (workspace_layout_find_exec(workspace, screen)) {
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/* -------------------------------------------------------------------- */
+/* Create, delete, init */
+
+WorkSpace *BKE_workspace_add(Main *bmain, const char *name)
+{
+	WorkSpace *new_workspace = BKE_libblock_alloc(bmain, ID_WS, name);
+	return new_workspace;
+}
+
+void BKE_workspace_free(WorkSpace *workspace)
+{
+	for (WorkSpaceDataRelation *relation = workspace->hook_layout_relations.first, *relation_next;
+	     relation;
+	     relation = relation_next)
+	{
+		relation_next = relation->next;
+		workspace_relation_remove(&workspace->hook_layout_relations, relation);
+	}
+	BLI_freelistN(&workspace->layouts);
+}
+
+void BKE_workspace_remove(Main *bmain, WorkSpace *workspace)
+{
+	for (WorkSpaceLayout *layout = workspace->layouts.first, *layout_next; layout; layout = layout_next) {
+		layout_next = layout->next;
+		BKE_workspace_layout_remove(bmain, workspace, layout);
+	}
+
+	BKE_libblock_free(bmain, workspace);
+}
+
+WorkSpaceInstanceHook *BKE_workspace_instance_hook_create(const Main *bmain)
+{
+	WorkSpaceInstanceHook *hook = MEM_callocN(sizeof(WorkSpaceInstanceHook), __func__);
+
+	/* set an active screen-layout for each possible window/workspace combination */
+	for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
+		BKE_workspace_hook_layout_for_workspace_set(hook, workspace, workspace->layouts.first);
+	}
+
+	return hook;
+}
+void BKE_workspace_instance_hook_free(const Main *bmain, WorkSpaceInstanceHook *hook)
+{
+	/* workspaces should never be freed before wm (during which we call this function) */
+	BLI_assert(!BLI_listbase_is_empty(&bmain->workspaces));
+
+	/* Free relations for this hook */
+	for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
+		for (WorkSpaceDataRelation *relation = workspace->hook_layout_relations.first, *relation_next;
+		     relation;
+		     relation = relation_next)
+		{
+			relation_next = relation->next;
+			if (relation->parent == hook) {
+				workspace_relation_remove(&workspace->hook_layout_relations, relation);
+			}
+		}
+	}
+
+	MEM_freeN(hook);
+}
+
+/**
+ * Add a new layout to \a workspace for \a screen.
+ */
+WorkSpaceLayout *BKE_workspace_layout_add(
+        WorkSpace *workspace,
+        bScreen *screen,
+        const char *name)
+{
+	WorkSpaceLayout *layout = MEM_callocN(sizeof(*layout), __func__);
+
+	BLI_assert(!workspaces_is_screen_used(G.main, screen));
+	layout->screen = screen;
+	workspace_layout_name_set(workspace, layout, name);
+	BLI_addtail(&workspace->layouts, layout);
+
+	return layout;
+}
+
+void BKE_workspace_layout_remove(
+        Main *bmain,
+        WorkSpace *workspace, WorkSpaceLayout *layout)
+{
+	BKE_libblock_free(bmain, BKE_workspace_layout_screen_get(layout));
+	BLI_freelinkN(&workspace->layouts, layout);
+}
+
+/* -------------------------------------------------------------------- */
+/* General Utils */
+
+WorkSpaceLayout *BKE_workspace_layout_find(
+        const WorkSpace *workspace, const bScreen *screen)
+{
+	WorkSpaceLayout *layout = workspace_layout_find_exec(workspace, screen);
+	if (layout) {
+		return layout;
+	}
+
+	printf("%s: Couldn't find layout in this workspace: '%s' screen: '%s'. "
+	       "This should not happen!\n",
+	       __func__, workspace->id.name + 2, screen->id.name + 2);
+
+	return NULL;
+}
+
+/**
+ * Find the layout for \a screen without knowing which workspace to look in.
+ *
+ * \param r_workspace: Optionally return the workspace that contains the looked up layout (if found).
+ */
+WorkSpaceLayout *BKE_workspace_layout_find_global(
+        const Main *bmain, const bScreen *screen,
+        WorkSpace **r_workspace)
+{
+	WorkSpaceLayout *layout;
+
+	if (r_workspace) {
+		*r_workspace = NULL;
+	}
+
+	for (WorkSpace *workspace = bmain->workspaces.first; workspace; workspace = workspace->id.next) {
+		if ((layout = workspace_layout_find_exec(workspace, screen))) {
+			if (r_workspace) {
+				*r_workspace = workspace;
+			}
+
+			return layout;
+		}
+	}
+
+	return NULL;
+}
+
+/**
+ * Circular workspace layout iterator.
+ *
+ * \param callback: Custom function which gets executed for each layout. Can return false to stop iterating.
+ * \param arg: Custom data passed to each \a callback call.
+ *
+ * \return the layout at which \a callback returned false.
+ */
+WorkSpaceLayout *BKE_workspace_layout_iter_circular(
+        const WorkSpace *workspace, WorkSpaceLayout *start,
+        bool (*callback)(const WorkSpaceLayout *layout, void *arg),
+        void *arg, const bool iter_backward)
+{
+	WorkSpaceLayout *iter_layout;
+
+	if (iter_backward) {
+		BLI_LISTBASE_CIRCULAR_BACKWARD_BEGIN(&workspace->layouts, iter_layout, start)
+		{
+			if (!callback(iter_layout, arg)) {
+				return iter_layout;
+			}
+		}
+		BLI_LISTBASE_CIRCULAR_BACKWARD_END(&workspace->layouts, iter_layout, start);
+	}
+	else {
+		BLI_LISTBASE_CIRCULAR_FORWARD_BEGIN(&workspace->layouts, iter_layout, start)
+		{
+			if (!callback(iter_layout, arg)) {
+				return iter_layout;
+			}
+		}
+		BLI_LISTBASE_CIRCULAR_FORWARD_END(&workspace->layouts, iter_layout, start)
+	}
+
+	return NULL;
+}
+
+
+/* -------------------------------------------------------------------- */
+/* Getters/Setters */
+
+WorkSpace *BKE_workspace_active_get(WorkSpaceInstanceHook *hook)
+{
+	return hook->active;
+}
+void BKE_workspace_active_set(WorkSpaceInstanceHook *hook, WorkSpace *workspace)
+{
+	hook->active = workspace;
+	if (workspace) {
+		WorkSpaceLayout *layout = workspace_relation_get_data_matching_parent(&workspace->hook_layout_relations, hook);
+		if (layout) {
+			hook->act_layout = layout;
+		}
+	}
+}
+
+WorkSpaceLayout *BKE_workspace_active_layout_get(const WorkSpaceInstanceHook *hook)
+{
+	return hook->act_layout;
+}
+void BKE_workspace_active_layout_set(WorkSpaceInstanceHook *hook, WorkSpaceLayout *layout)
+{
+	hook->act_layout = layout;
+}
+
+bScreen *BKE_workspace_active_screen_get(const WorkSpaceInstanceHook *hook)
+{
+	return hook->act_layout->screen;
+}
+void BKE_workspace_active_screen_set(WorkSpaceInstanceHook *hook, WorkSpace *workspace, bScreen *screen)
+{
+	/* we need to find the WorkspaceLayout that wraps this screen */
+	WorkSpaceLayout *layout = BKE_workspace_layout_find(hook->active, screen);
+	BKE_workspace_hook_layout_for_workspace_set(hook, workspace, layout);
+}
+
+#ifdef USE_WORKSPACE_MODE
+ObjectMode BKE_workspace_object_mode_get(const WorkSpace *workspace)
+{
+	return workspace->object_mode;
+}
+void BKE_workspace_object_mode_set(WorkSpace *workspace, const ObjectMode mode)
+{
+	workspace->object_mode = mode;
+}
+#endif
+
+SceneLayer *BKE_workspace_render_layer_get(const WorkSpace *workspace)
+{
+	return workspace->render_layer;
+}
+void BKE_workspace_render_layer_set(WorkSpace *workspace, SceneLayer *layer)
+{
+	workspace->render_layer = layer;
+}
+
+ListBase *BKE_workspace_layouts_get(WorkSpace *workspace)
+{
+	return &workspace->layouts;
+}
+
+
+const char *BKE_workspace_layout_name_get(const WorkSpaceLayout *layout)
+{
+	return layout->name;
+}
+void BKE_workspace_layout_name_set(WorkSpace *workspace, WorkSpaceLayout *layout, const char *new_name)
+{
+	workspace_layout_name_set(workspace, layout, new_name);
+}
+
+bScreen *BKE_workspace_layout_screen_get(const WorkSpaceLayout *layout)
+{
+	return layout->screen;
+}
+void BKE_workspace_layout_screen_set(WorkSpaceLayout *layout, bScreen *screen)
+{
+	layout->screen = screen;
+}
+
+WorkSpaceLayout *BKE_workspace_hook_layout_for_workspace_get(
+        const WorkSpaceInstanceHook *hook, const WorkSpace *workspace)
+{
+	return workspace_relation_get_data_matching_parent(&workspace->hook_layout_relations, hook);
+}
+void BKE_workspace_hook_layout_for_workspace_set(
+        WorkSpaceInstanceHook *hook, WorkSpace *workspace, WorkSpaceLayout *layout)
+{
+	hook->act_layout = layout;
+	workspace_relation_ensure_updated(&workspace->hook_layout_relations, hook, layout);
+}