[PATCH 0/1] MR8467: conhost: Implement F1 and F3 support for history retrieval.

[Joe Souza (＠JoeS209)]

F1 and F3 allow partial retrieval of previous entry from console history.  They are used as shortcuts such that if the following were entered at the command line:

md tmptmp
cd <F3>

F3 will retrieve the previous line from history past the cursor position, and be auto-completed to "cd tmptmp".  F1 works in a similar fashion, but with one character at a time.

[PATCH 1/1] conhost: Implement F1 and F3 support for history retrieval.

[Joe Souza]

From: Joe Souza

---
 programs/conhost/conhost.c | 70 +++++++++++++++++++++++++++++++++-----
 1 file changed, 61 insertions(+), 9 deletions(-)

diff --git a/programs/conhost/conhost.c b/programs/conhost/conhost.c
index 89c030e86c8..44d24ab30f9 100644
--- a/programs/conhost/conhost.c
+++ b/programs/conhost/conhost.c
@@ -774,6 +774,56 @@ static void edit_line_find_in_history( struct console *console )
     while (ctx->history_index != start_pos);
 }

+static void edit_line_copy_from_hist( struct console *console, int copycount )
+{
+    if (console->edit_line.history_index)
+    {
+        int index = console->edit_line.history_index - 1;
+        struct edit_line *ctx = &console->edit_line;
+        WCHAR *line = edit_line_history(console, index);
+        size_t len = line ? lstrlenW(line) : 0;
+        rsize_t ccount = (copycount > 0) ? copycount : _TRUNCATE;
+
+        if (len > ctx->cursor)
+        {
+            WCHAR *tmp = malloc( (len + 1) * sizeof(WCHAR) );
+            if (!tmp)
+            {
+                ctx->status = STATUS_NO_MEMORY;
+                return;
+            }
+
+            /* Copy current line to our work buffer. */
+            wcsncpy_s(tmp, len + 1, ctx->buf, _TRUNCATE);
+            /* Overwrite the string in the work buffer starting at the cursor, with the
+               string from history. */
+            wcsncpy_s(&tmp[ctx->cursor], len - ctx->cursor + 1, &line[ctx->cursor], ccount);
+            len = lstrlenW(tmp);
+
+            /* Clean the screen. */
+            edit_line_delete(console, 0, ctx->len);
+            ctx->cursor = 0;
+            /* Insert new string. */
+            if (edit_line_grow(console, len + 1))
+            {
+                edit_line_insert( console, tmp, len );
+            }
+            free(tmp);
+        }
+        free(line);
+    }
+}
+
+static void edit_line_copy_one_from_hist( struct console *console )
+{
+    edit_line_copy_from_hist(console, 1);
+}
+
+static void edit_line_copy_all_from_hist( struct console *console )
+{
+    edit_line_copy_from_hist(console, -1);
+}
+
 static void edit_line_move_left( struct console *console )
 {
     if (console->edit_line.cursor > 0) console->edit_line.cursor--;
@@ -1137,15 +1187,17 @@ static const struct edit_line_key_map emacs_key_map[] =

static const struct edit_line_key_entry win32_std_key_map[] =
 {
-    { VK_LEFT,   edit_line_move_left         },
-    { VK_RIGHT,  edit_line_move_right        },
-    { VK_HOME,   edit_line_move_home         },
-    { VK_END,    edit_line_move_end          },
-    { VK_UP,     edit_line_move_to_prev_hist },
-    { VK_DOWN,   edit_line_move_to_next_hist },
-    { VK_INSERT, edit_line_toggle_insert     },
-    { VK_F8,     edit_line_find_in_history   },
-    { VK_ESCAPE, edit_line_clear             },
+    { VK_LEFT,   edit_line_move_left          },
+    { VK_RIGHT,  edit_line_move_right         },
+    { VK_HOME,   edit_line_move_home          },
+    { VK_END,    edit_line_move_end           },
+    { VK_UP,     edit_line_move_to_prev_hist  },
+    { VK_DOWN,   edit_line_move_to_next_hist  },
+    { VK_INSERT, edit_line_toggle_insert      },
+    { VK_F8,     edit_line_find_in_history    },
+    { VK_ESCAPE, edit_line_clear              },
+    { VK_F1,     edit_line_copy_one_from_hist },
+    { VK_F3,     edit_line_copy_all_from_hist },
     { 0 }
 };

[eric pouech (＠epo)]

didn't look in details yet, but I don't see the need for an intermediate buffer. you just need to edit_line_delete( console, ctx->cursor, ctx->len ); to clear edit line after cursor, then insert history line + ctx->cursor, length 1 or til end of line.

also quick testing on windows rather suggests that's the current_history line that should be used instead of last line in history

I didn't check if history is modified by these operations