From ebed165be8af3d7e145e1defa97892fdf9ddf560 Mon Sep 17 00:00:00 2001
From: Gustaf Waldemarson <gustaf.waldemarson@gmail.com>
Date: Thu, 21 Feb 2019 13:37:14 +0100
Subject: [PATCH 1/2] gdb-mi.el: Display complex data-types.

Create a new gdb buffer for extracting local variable values. To
extract the values for 'complex' data-types, the command
`-stack-list-locals` is used with the `--all-values` flag.

The extracted values are then stored in a hash-table for later use in
the `gdb-locals-handler-custom` that performs the actual update of the
Local variable buffer.

All variable values are filtered to fit it into a single line, being
truncated as necessary by the user customizable option
`gdb-locals-value-limit`.

The old behavior of hiding complex values can be restored using the
customizable `gdb-locals-simple-values-only` option.
---
 lisp/progmodes/gdb-mi.el | 69 +++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 66 insertions(+), 3 deletions(-)

diff --git a/lisp/progmodes/gdb-mi.el b/lisp/progmodes/gdb-mi.el
index b63f82b..6fb09d1 100644
--- a/lisp/progmodes/gdb-mi.el
+++ b/lisp/progmodes/gdb-mi.el
@@ -4119,6 +4119,51 @@ gdb-select-frame
  'gdb-locals-mode
  'gdb-invalidate-locals)
 
+
+;; Retrieve the values of all variables before invalidating locals.
+(def-gdb-trigger-and-handler
+  gdb-locals-values
+  (concat (gdb-current-context-command "-stack-list-locals")
+          " --all-values")
+  gdb-locals-values-handler gdb-locals-values-handler-custom
+  '(start update))
+
+(gdb-set-buffer-rules
+ 'gdb-locals-values-buffer
+ 'gdb-locals-values-buffer-name
+ 'gdb-locals-mode
+ 'gdb-locals-values)
+
+(defun gdb-locals-values-buffer-name ()
+  (gdb-current-context-buffer-name
+   (concat "local values of " (gdb-get-target-string))))
+
+
+(defcustom gdb-locals-simple-values-only nil
+  "Only display simple values in the Locals buffer."
+  :type 'boolean
+  :group 'gud)
+
+
+(defcustom gdb-locals-value-limit 100
+  "Maximum length the value of a local variable is allowed to be."
+  :type 'integer
+  :group 'gud)
+
+
+(defvar gdb-locals-values-table (make-hash-table :test #'equal)
+  "Mapping of local variable names to a string with their value.")
+
+
+(defun gdb-locals-values-handler-custom ()
+  "Store the values of local variables in `gdb-locals-value-map'."
+  (let ((locals-list (bindat-get-field (gdb-json-partial-output) 'locals)))
+    (dolist (local locals-list)
+      (let ((name (bindat-get-field local 'name))
+            (value (bindat-get-field local 'value)))
+        (puthash name value gdb-locals-values-table)))))
+
+
 (defvar gdb-locals-watch-map
   (let ((map (make-sparse-keymap)))
     (suppress-keymap map)
@@ -4135,6 +4180,17 @@ gdb-edit-locals-map-1
     map)
   "Keymap to edit value of a simple data type local variable.")
 
+
+(defun gdb-locals-value-filter (value)
+  "Filter function for the local variable VALUE."
+  (let* ((no-nl (replace-regexp-in-string "\n" " " value))
+         (str (replace-regexp-in-string "[[:space:]]+" " " no-nl))
+         (limit gdb-locals-value-limit))
+    (if (>= (length str) limit)
+        (concat (substring str 0 limit) "...")
+      str)))
+
+
 (defun gdb-edit-locals-value (&optional event)
   "Assign a value to a variable displayed in the locals buffer."
   (interactive (list last-input-event))
@@ -4147,9 +4203,10 @@ gdb-edit-locals-value
       (gud-basic-call
        (concat  "-gdb-set variable " var " = " value)))))
 
-;; Don't display values of arrays or structures.
-;; These can be expanded using gud-watch.
+
+;; Complex data types are looked up in `gdb-locals-values-table'.
 (defun gdb-locals-handler-custom ()
+  "Handler to rebuild the local variables table buffer."
   (let ((locals-list (bindat-get-field (gdb-json-partial-output) 'locals))
         (table (make-gdb-table)))
     (dolist (local locals-list)
@@ -4157,7 +4214,11 @@ gdb-locals-handler-custom
             (value (bindat-get-field local 'value))
             (type (bindat-get-field local 'type)))
         (when (not value)
-          (setq value "<complex data type>"))
+          (setq value
+                (if gdb-locals-simple-values-only
+                    "<complex data type>"
+                  (gethash name gdb-locals-values-table "<unavailable>"))))
+        (setq value (gdb-locals-value-filter value))
         (if (or (not value)
                 (string-match "\\0x" value))
             (add-text-properties 0 (length name)
@@ -4581,6 +4642,8 @@ gdb-set-window-buffer
 
 (defun gdb-setup-windows ()
   "Layout the window pattern for option `gdb-many-windows'."
+  ;; Make sure that local values are updated before locals.
+  (gdb-get-buffer-create 'gdb-locals-values-buffer)
   (gdb-get-buffer-create 'gdb-locals-buffer)
   (gdb-get-buffer-create 'gdb-stack-buffer)
   (gdb-get-buffer-create 'gdb-breakpoints-buffer)
-- 
2.7.4