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Windows Pageant: use an owner-drawn list box for the key list.

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The main key list control in the Pageant window was previously an
ordinary LBS_HASSTRINGS list box, with tab characters aligning the
various parts of the key information into different columns. This was
fragile because any mistake in the font metrics could have overflowed
a tab stop and forced the text to move on to the next one.

Now I've switched the list box into LBS_OWNERDRAWFIXED mode, which
means that in place of a string for each list item I store a struct of
my choice, and I have to draw the list-box entries myself by
responding to WM_DRAWITEM. So now I'm drawing each component of the
key information as a separate call to ExtTextOut (plus one
TabbedTextOut to put the '(encrypted)' suffix on the end), which means
that the tab stops are now guaranteed to appear where I tell them to.

No functional change, for the moment: this is pure refactoring. As
closely as I can tell, the appearance of the list box is
pixel-for-pixel what it was before this commit. But it opens the door
for two further improvements (neither one done in this commit): I can
dynamically choose the tab stop locations based on querying the text
metrics of the strings that will actually need to fit in the columns,
and also, whatever reorganisation I need to do to make certificates
fit sensibly in this list box can now be done without worrying about
breaking anything terribly fragile.
This commit is contained in:
Simon Tatham 2022-08-01 17:45:55 +01:00
parent 932f6f5387
commit 3e7274fdad
2 changed files with 159 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

215
windows/pageant.c
View File

@ -317,14 +317,24 @@ struct keylist_update_ctx {
bool enable_reencrypt_controls;
};
struct keylist_display_data {
strbuf *alg, *bits, *hash, *comment, *info;
};
static void keylist_update_callback(
void *vctx, char **fingerprints, const char *comment, uint32_t ext_flags,
struct pageant_pubkey *key)
{
struct keylist_update_ctx *ctx = (struct keylist_update_ctx *)vctx;
FingerprintType this_type = ssh2_pick_fingerprint(fingerprints, fptype);
const char *fingerprint = fingerprints[this_type];
strbuf *listentry = strbuf_new();
ptrlen fingerprint = ptrlen_from_asciz(fingerprints[this_type]);
struct keylist_display_data *disp = snew(struct keylist_display_data);
disp->alg = strbuf_new();
disp->bits = strbuf_new();
disp->hash = strbuf_new();
disp->comment = strbuf_new();
disp->info = strbuf_new();
/* There is at least one key, so the controls for removing keys
* should be enabled */
@ -332,76 +342,55 @@ static void keylist_update_callback(
switch (key->ssh_version) {
case 1: {
put_fmt(listentry, "ssh1\t%s\t%s", fingerprint, comment);
/*
* Replace the space in the fingerprint (between bit count and
* hash) with a tab, for nice alignment in the box.
* Expect the fingerprint to contain two words: bit count and
* hash.
*/
char *p = strchr(listentry->s, ' ');
if (p)
*p = '\t';
put_dataz(disp->alg, "ssh1");
put_datapl(disp->bits, ptrlen_get_word(&fingerprint, " "));
put_datapl(disp->hash, ptrlen_get_word(&fingerprint, " "));
break;
}
case 2: {
/*
* For nice alignment in the list box, we would ideally want
* every entry to align to the tab stop settings, and have a
* column for algorithm name, one for bit count, one for hex
* fingerprint, and one for key comment.
*
* Unfortunately, some of the algorithm names are so long that
* they overflow into the bit-count field. Fortunately, at the
* moment, those are _precisely_ the algorithm names that
* don't need a bit count displayed anyway (because for
* NIST-style ECDSA the bit count is mentioned in the
* algorithm name, and for ssh-ed25519 there is only one
* possible value anyway). So we fudge this by simply omitting
* the bit count field in that situation.
*
* This is fragile not only in the face of further key types
* that don't follow this pattern, but also in the face of
* font metrics changes - the Windows semantics for list box
* tab stops is that \t aligns to the next one you haven't
* already exceeded, so I have to guess when the key type will
* overflow past the bit-count tab stop and leave out a tab
* character. Urgh.
* Expect the fingerprint to contain three words: algorithm
* name, bit count, hash.
*/
put_datapl(disp->alg, ptrlen_get_word(&fingerprint, " "));
put_datapl(disp->bits, ptrlen_get_word(&fingerprint, " "));
put_datapl(disp->hash, ptrlen_get_word(&fingerprint, " "));
/*
* But we don't display the bit count if the algorithm isn't
* one of the ones where it can vary. That way, those
* algorithm names (which are generally longer) can safely
* overlap into the bits column without colliding with
* pointless text.
*/
const ssh_keyalg *alg = pubkey_blob_to_alg(
ptrlen_from_strbuf(key->blob));
bool include_bit_count = (alg == &ssh_dsa || alg == &ssh_rsa);
int wordnumber = 0;
for (const char *p = fingerprint; *p; p++) {
char c = *p;
if (c == ' ') {
if (wordnumber < 2)
c = '\t';
wordnumber++;
}
if (include_bit_count || wordnumber != 1)
put_byte(listentry, c);
}
put_fmt(listentry, "\t%s", comment);
break;
if (!(alg == &ssh_dsa || alg == &ssh_rsa))
strbuf_clear(disp->bits);
}
}
put_dataz(disp->comment, comment);
if (ext_flags & LIST_EXTENDED_FLAG_HAS_NO_CLEARTEXT_KEY) {
put_fmt(listentry, "\t(encrypted)");
put_fmt(disp->info, "(encrypted)");
} else if (ext_flags & LIST_EXTENDED_FLAG_HAS_ENCRYPTED_KEY_FILE) {
put_fmt(listentry, "\t(re-encryptable)");
put_fmt(disp->info, "(re-encryptable)");
/* At least one key can be re-encrypted */
ctx->enable_reencrypt_controls = true;
}
/* This list box is owner-drawn but doesn't have LBS_HASSTRINGS,
* so we can use LB_ADDSTRING to hand the list box our display
* info pointer */
SendDlgItemMessage(keylist, IDC_KEYLIST_LISTBOX,
LB_ADDSTRING, 0, (LPARAM)listentry->s);
strbuf_free(listentry);
LB_ADDSTRING, 0, (LPARAM)disp);
}
/*
@ -410,6 +399,25 @@ static void keylist_update_callback(
void keylist_update(void)
{
if (keylist) {
/*
* Clear the previous list box content and free their display
* structures.
*/
{
int nitems = SendDlgItemMessage(keylist, IDC_KEYLIST_LISTBOX,
LB_GETCOUNT, 0, 0);
for (int i = 0; i < nitems; i++) {
struct keylist_display_data *disp =
(struct keylist_display_data *)SendDlgItemMessage(
keylist, IDC_KEYLIST_LISTBOX, LB_GETITEMDATA, i, 0);
strbuf_free(disp->alg);
strbuf_free(disp->bits);
strbuf_free(disp->hash);
strbuf_free(disp->comment);
strbuf_free(disp->info);
sfree(disp);
}
}
SendDlgItemMessage(keylist, IDC_KEYLIST_LISTBOX,
LB_RESETCONTENT, 0, 0);
@ -582,12 +590,6 @@ static INT_PTR CALLBACK KeyListProc(HWND hwnd, UINT msg,
}
keylist = hwnd;
{
static int tabs[] = { 35, 75, 300 };
SendDlgItemMessage(hwnd, IDC_KEYLIST_LISTBOX, LB_SETTABSTOPS,
sizeof(tabs) / sizeof(*tabs),
(LPARAM) tabs);
}
int selection = 0;
for (size_t i = 0; i < lenof(fptypes); i++) {
@ -602,6 +604,105 @@ static INT_PTR CALLBACK KeyListProc(HWND hwnd, UINT msg,
keylist_update();
return 0;
}
case WM_MEASUREITEM: {
assert(wParam == IDC_KEYLIST_LISTBOX);
MEASUREITEMSTRUCT *mi = (MEASUREITEMSTRUCT *)lParam;
/*
* Our list box is owner-drawn, but we put normal text in it.
* So the line height is the same as it would normally be,
* which is 8 dialog units.
*/
RECT r;
r.left = r.right = r.top = 0;
r.bottom = 8;
MapDialogRect(hwnd, &r);
mi->itemHeight = r.bottom;
return 0;
}
case WM_DRAWITEM: {
assert(wParam == IDC_KEYLIST_LISTBOX);
DRAWITEMSTRUCT *di = (DRAWITEMSTRUCT *)lParam;
if (di->itemAction == ODA_FOCUS) {
/* Just toggle the focus rectangle either on or off. This
* is an XOR-type function, so it's the same call in
* either case. */
DrawFocusRect(di->hDC, &di->rcItem);
} else {
/* Draw the full text. */
bool selected = (di->itemState & ODS_SELECTED);
COLORREF newfg = GetSysColor(
selected ? COLOR_HIGHLIGHTTEXT : COLOR_WINDOWTEXT);
COLORREF newbg = GetSysColor(
selected ? COLOR_HIGHLIGHT : COLOR_WINDOW);
COLORREF oldfg = SetTextColor(di->hDC, newfg);
COLORREF oldbg = SetBkColor(di->hDC, newbg);
HFONT font = (HFONT)SendMessage(hwnd, WM_GETFONT, 0, 0);
HFONT oldfont = SelectObject(di->hDC, font);
/* ExtTextOut("") is an easy way to just draw the
* background rectangle */
ExtTextOut(di->hDC, di->rcItem.left, di->rcItem.top,
ETO_OPAQUE | ETO_CLIPPED, &di->rcItem, "", 0, NULL);
struct keylist_display_data *disp =
(struct keylist_display_data *)di->itemData;
RECT r;
/* Apparently real list boxes start drawing at x=1, not x=0 */
r.left = r.top = r.bottom = 0;
r.right = 1;
MapDialogRect(hwnd, &r);
ExtTextOut(di->hDC, di->rcItem.left + r.right, di->rcItem.top,
ETO_CLIPPED, &di->rcItem, disp->alg->s,
disp->alg->len, NULL);
if (disp->bits->len) {
r.left = r.top = r.bottom = 0;
r.right = 35;
MapDialogRect(hwnd, &r);
ExtTextOut(di->hDC, di->rcItem.left + r.right, di->rcItem.top,
ETO_CLIPPED, &di->rcItem, disp->bits->s,
disp->bits->len, NULL);
}
r.left = r.top = r.bottom = 0;
r.right = 75;
MapDialogRect(hwnd, &r);
ExtTextOut(di->hDC, di->rcItem.left + r.right, di->rcItem.top,
ETO_CLIPPED, &di->rcItem, disp->hash->s,
disp->hash->len, NULL);
strbuf *sb = strbuf_new();
put_datapl(sb, ptrlen_from_strbuf(disp->comment));
if (disp->info->len) {
put_byte(sb, '\t');
put_datapl(sb, ptrlen_from_strbuf(disp->info));
}
r.left = r.top = r.bottom = 0;
r.right = 300;
MapDialogRect(hwnd, &r);
TabbedTextOut(di->hDC, di->rcItem.left + r.right, di->rcItem.top,
sb->s, sb->len, 0, NULL, 0);
strbuf_free(sb);
SetTextColor(di->hDC, oldfg);
SetBkColor(di->hDC, oldbg);
SelectObject(di->hDC, oldfont);
if (di->itemState & ODS_FOCUS)
DrawFocusRect(di->hDC, &di->rcItem);
}
return 0;
}
case WM_COMMAND:
switch (LOWORD(wParam)) {
case IDOK:

2
windows/pageant.rc
View File

@ -52,7 +52,7 @@ CAPTION "Pageant Key List"
FONT 8, "MS Shell Dlg"
BEGIN
LISTBOX IDC_KEYLIST_LISTBOX, 10, 10, 420, 155,
LBS_EXTENDEDSEL | LBS_HASSTRINGS | LBS_USETABSTOPS | WS_VSCROLL | WS_TABSTOP
LBS_EXTENDEDSEL | LBS_OWNERDRAWFIXED | WS_VSCROLL | WS_TABSTOP
PUSHBUTTON "&Add Key", IDC_KEYLIST_ADDKEY, 10, 187, 60, 14
PUSHBUTTON "Add Key (&encrypted)", IDC_KEYLIST_ADDKEY_ENC, 75, 187, 80, 14
PUSHBUTTON "Re-e&ncrypt", IDC_KEYLIST_REENCRYPT, 315, 187, 60, 14