From 28423d0de37eabbdbe2a85dbfeec4db4c777706a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Mon, 27 Mar 2023 11:10:15 +0300
Subject: [PATCH] Re-render file window in shell if directory has changed

---
 shell.asm | 98 ++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 65 insertions(+), 33 deletions(-)

diff --git a/shell.asm b/shell.asm
index 63f0fe1..36ed9ad 100644
--- a/shell.asm
+++ b/shell.asm
@@ -141,6 +141,24 @@ paint:
 	mov bx, [si + window.next]
 	call forward_event
 
+	cmp si, windows + 1*window.size
+	jne .not_file_window
+	.file_window:
+		; See if the dirents have changed since we rendered the
+		; window contents. If yes, rerender.
+		push si
+		mov bp, PONYDOS_SEG
+		mov es, bp
+		mov si, dirents
+		mov di, GLOBAL_DIRENTS
+		mov cx, FS_DIRENT_SIZE*FS_DIRECTORY_DIRENTS
+		repe cmpsb
+		pop si
+		je .no_rerender
+		call render_file_window
+		.no_rerender:
+	.not_file_window:
+
 	; Draw a rectangle on-screen
 	mov bx, [si + window.width]
 	mov dx, [si + window.height]
@@ -399,21 +417,13 @@ click:
 		cmp ax, FS_DIRECTORY_DIRENTS
 		jae .end
 
-		push ds
-
-		mov bp, PONYDOS_SEG
-		mov ds, bp
-
 		mov bp, FS_DIRENT_SIZE
 		mul bp
-		mov si, GLOBAL_DIRENTS
+		mov si, dirents
 		add si, ax
 
 		cmp word [si], 0
-		jne .dirent_present
-		pop ds
-		jmp .end
-		.dirent_present:
+		je .end
 
 		; Copy file name to launch_filename
 		add si, FS_DIRENT_NAME_OFFSET
@@ -421,8 +431,6 @@ click:
 		mov cx, FS_DIRENT_NAME_SIZE
 		rep movsb
 
-		pop ds
-
 		call launch
 
 	.end:
@@ -433,6 +441,8 @@ click:
 ; in
 ;  si = pointer to window structure
 render_file_window:
+	call copy_dirents
+
 	push ax
 	push cx
 	push dx
@@ -468,6 +478,30 @@ render_file_window:
 	pop ax
 	ret
 
+copy_dirents:
+	push cx
+	push si
+	push di
+	push ds
+	push es
+
+	mov bp, PONYDOS_SEG
+	mov ds, bp
+	mov bp, cs
+	mov es, bp
+
+	mov si, GLOBAL_DIRENTS
+	mov di, dirents
+	mov cx, FS_DIRENT_SIZE*FS_DIRECTORY_DIRENTS
+	rep movsb
+
+	pop es
+	pop ds
+	pop di
+	pop si
+	pop cx
+	ret
+
 show_file_window:
 	cmp byte [file_window_visible], 0
 	jne .already_visible
@@ -753,18 +787,14 @@ print_ls:
 	push si
 	push di
 	push bp
-	push ds
-
-	mov bp, PONYDOS_SEG
-	mov ds, bp
 
 	push cx
 	push di
-	mov si, GLOBAL_DIRENTS + FS_DIRENT_NAME_OFFSET
+	mov si, dirents + FS_DIRENT_NAME_OFFSET
 
 	xor ax, ax ; Maximum filename size
 	.name_loop:
-		cmp word [ds:si - FS_DIRENT_NAME_OFFSET], 0
+		cmp word [si - FS_DIRENT_NAME_OFFSET], 0
 		je .done_names
 
 		push cx
@@ -797,7 +827,7 @@ print_ls:
 		add di, dx
 
 		add si, FS_DIRENT_SIZE
-		cmp si, GLOBAL_DIRENTS + FS_DIRECTORY_DIRENTS*FS_DIRENT_SIZE
+		cmp si, dirents + FS_DIRECTORY_DIRENTS*FS_DIRENT_SIZE
 		jge .done_names
 
 		dec cx
@@ -820,13 +850,13 @@ print_ls:
 
 	add di, ax
 	add di, ax
-	mov si, GLOBAL_DIRENTS
+	mov si, dirents
 	.size_loop:
-		mov ax, word [ds:si]
+		mov ax, word [si]
 		test ax, ax
 		jz .done
 
-		mov byte [es:di + 8], 'K'
+		mov byte [di + 8], 'K'
 
 		shr ax, 1
 		aam ; mango
@@ -834,23 +864,23 @@ print_ls:
 		cmp ah, 0x30
 		je .one_digit
 
-		mov byte [es:di + 2], ' '
-		mov [es:di + 4], ah
+		mov byte [di + 2], ' '
+		mov [di + 4], ah
 		jmp .one_digit_print
 
 		.one_digit:
-			test word [ds:si], 1
+			test word [si], 1
 			jnz .one_and_half_digit
-			mov byte [es:di + 4], ' '
+			mov byte [di + 4], ' '
 		.one_digit_print:
-			mov [es:di + 6], al
+			mov [di + 6], al
 			jmp .next_iter_size_loop
 
 		.one_and_half_digit:
-			mov byte [es:di], ' '
-			mov byte [es:di + 2], al
-			mov byte [es:di + 4], '.'
-			mov byte [es:di + 6], '5'
+			mov byte [di], ' '
+			mov byte [di + 2], al
+			mov byte [di + 4], '.'
+			mov byte [di + 6], '5'
 
 		.next_iter_size_loop:
 		; Move to next line
@@ -858,14 +888,13 @@ print_ls:
 		add di, dx
 
 		add si, FS_DIRENT_SIZE
-		cmp si, GLOBAL_DIRENTS + 0x200
+		cmp si, dirents + FS_DIRECTORY_DIRENTS*FS_DIRENT_SIZE
 		jge .done
 
 		dec cx
 		jnz .size_loop
 
 	.done:
-	pop ds
 	pop bp
 	pop di
 	pop si
@@ -975,5 +1004,8 @@ windows:
 launch_filename times FS_DIRENT_NAME_SIZE db 0
 
 section .bss
+dirents:
+	resb FS_DIRENT_SIZE*FS_DIRECTORY_DIRENTS
+
 file_window:
 	resw ROWS*COLUMNS