Merge branch '2023-10-12-expo-add-support-for-edting-lines-of-text'

To quote the author:
So far expo only supports menus. These are quite flexible for various
kinds of settings, but cannot deal with free-form input, such as a
serial number or a machine name.

This series adds support for a textline object, which is a single line
of text. It has a maximum length and its value is stored within the expo
structure.

U-Boot already has a command-line editor which provides most of the
features needed by expo. But the code runs in its own loop and only
returns when the line is finished. This is not suitable for expo, which
must handle a keypress at a time, returning to its caller after each
one.

In order to use the CLI code, some significant refactoring is included
here. This mostly involves moving the internal loop of the CLI to a
separate function and recording its state in a struct, just as was done
for single keypresses some time back. A minor addition is support for
Ctrl-W to delete a word, since strangely this is currently only present
in the simple version.

The video-console system provides most of the features needed by
testline, but a few things are missing. This series provides:

- primitive cursor support so the user can see where he is typing
- saving and restoring of the text-entry context, so that expo can allow
  the user to continue where he left off, including deleting previously
  entered characters correctly (for Truetype)
- obtaining the nominal width of a string of n characters, so that a
  suitable width can be chosen for the textline object

Note that no support is provided for clearing the cursor. This was
addressed in a previous series[1] which could perhaps be rebased. For
this implementation, the cursor is therefore not enabled for the normal
command line, only for expo.

Reading and writing textline objects is supported for FDT and
environment, but not for CMOS RAM, since it would likely use too much
RAM to store a string.

In terms of code size, the overall size increase is 180 bytes for
Thumb02 boards, 160 of whcih is the addition of Ctrl-W to delete a word.

[1] https://patchwork.ozlabs.org/project/uboot/list/?series=280178&state=*

1 files changed, 59 insertions, 1 deletions

diff --git a/include/expo.h b/include/expo.h
index 9d2e817eb97..264745f7f01 100644
--- a/include/expo.h
+++ b/include/expo.h
@@ -7,11 +7,14 @@
 #ifndef __EXPO_H
 #define __EXPO_H
 
+#include <abuf.h>
 #include <dm/ofnode_decl.h>
 #include <linux/list.h>
 
 struct udevice;
 
+#include <cli.h>
+
 /**
  * enum expoact_type - types of actions reported by the expo
  *
@@ -121,6 +124,9 @@ struct expo_string {
  * @id: ID number of the scene
  * @title_id: String ID of title of the scene (allocated)
  * @highlight_id: ID of highlighted object, if any
+ * @cls: cread state to use for input
+ * @buf: Buffer for input
+ * @entry_save: Buffer to hold vidconsole text-entry information
  * @sibling: Node to link this scene to its siblings
  * @obj_head: List of objects in the scene
  */
@@ -130,6 +136,9 @@ struct scene {
 	uint id;
 	uint title_id;
 	uint highlight_id;
+	struct cli_line_state cls;
+	struct abuf buf;
+	struct abuf entry_save;
 	struct list_head sibling;
 	struct list_head obj_head;
 };
@@ -141,12 +150,16 @@ struct scene {
  * @SCENEOBJT_IMAGE: Image data to render
  * @SCENEOBJT_TEXT: Text line to render
  * @SCENEOBJT_MENU: Menu containing items the user can select
+ * @SCENEOBJT_TEXTLINE: Line of text the user can edit
  */
 enum scene_obj_t {
 	SCENEOBJT_NONE		= 0,
 	SCENEOBJT_IMAGE,
 	SCENEOBJT_TEXT,
+
+	/* types from here on can be highlighted */
 	SCENEOBJT_MENU,
+	SCENEOBJT_TEXTLINE,
 };
 
 /**
@@ -178,6 +191,11 @@ enum scene_obj_flags_t {
 	SCENEOF_OPEN	= 1 << 2,
 };
 
+enum {
+	/* Maximum number of characters allowed in an line editor */
+	EXPO_MAX_CHARS		= 250,
+};
+
 /**
  * struct scene_obj - information about an object in a scene
  *
@@ -203,6 +221,12 @@ struct scene_obj {
 	struct list_head sibling;
 };
 
+/* object can be highlighted when moving around expo */
+static inline bool scene_obj_can_highlight(const struct scene_obj *obj)
+{
+	return obj->type >= SCENEOBJT_MENU;
+}
+
 /**
  * struct scene_obj_img - information about an image object in a scene
  *
@@ -297,6 +321,27 @@ struct scene_menitem {
 };
 
 /**
+ * struct scene_obj_textline - information about a textline in a scene
+ *
+ * A textline has a prompt and a line of editable text
+ *
+ * @obj: Basic object information
+ * @label_id: ID of the label text, or 0 if none
+ * @edit_id: ID of the editable text
+ * @max_chars: Maximum number of characters allowed
+ * @buf: Text buffer containing current text
+ * @pos: Cursor position
+ */
+struct scene_obj_textline {
+	struct scene_obj obj;
+	uint label_id;
+	uint edit_id;
+	uint max_chars;
+	struct abuf buf;
+	uint pos;
+};
+
+/**
  * expo_new() - create a new expo
  *
  * Allocates a new expo
@@ -505,7 +550,7 @@ int scene_txt(struct scene *scn, const char *name, uint id, uint str_id,
 	      struct scene_obj_txt **txtp);
 
 /**
- * scene_txt_str() - add a new string to expr and text object to a scene
+ * scene_txt_str() - add a new string to expo and text object to a scene
  *
  * @scn: Scene to update
  * @name: Name to use (this is allocated by this call)
@@ -531,6 +576,19 @@ int scene_menu(struct scene *scn, const char *name, uint id,
 	       struct scene_obj_menu **menup);
 
 /**
+ *  scene_textline() - create a textline
+ *
+ * @scn: Scene to update
+ * @name: Name to use (this is allocated by this call)
+ * @id: ID to use for the new object (0 to allocate one)
+ * @max_chars: Maximum length of the textline in characters
+ * @tlinep: If non-NULL, returns the new object
+ * Returns: ID number for the object (typically @id), or -ve on error
+ */
+int scene_textline(struct scene *scn, const char *name, uint id, uint max_chars,
+		   struct scene_obj_textline **tlinep);
+
+/**
  * scene_txt_set_font() - Set the font for an object
  *
  * @scn: Scene to update