On Tue, Nov 19, 2019 at 04:02:48PM +1300, Thomas Munro wrote:
> On Tue, Nov 19, 2019 at 12:09 PM Tom Lane <t...@sss.pgh.pa.us> wrote:
> > You should follow the logic in pg_wcswidth: compute PQmblen() first,
> > and bail out if it's more than the remaining string length, otherwise
> > it's ok to apply PQdsplen().
>
> Got it. I was worried that it wasn't safe to call even PQmblen(),
> because I didn't know a fact about all encodings: as described in the
> comment of pg_gb18030_mblen(), all implementations read only the first
> byte to determine the length, except for GB18030 which reads the
> second byte too, and that's OK because there's always a null
> terminator.
>
> > It might be a good idea to explicitly initialize last_prompt1_width to
> > zero, for clarity.
> >
> > Should the user docs explicitly say "of the same width as the most recent
> > output of PROMPT1", as you have in the comments? That seems a more
> > precise specification, and it will eliminate some questions people will
> > otherwise ask.
> >
> > LGTM otherwise.
>
> Done, and pushed. I also skipped negative results from PQdsplen like
> pg_wcswidth() does (that oversight explained why a non-readline build
> showed the correct alignment for PROMPT1 '%[%033[1m%]%M
> %n@%/%R%[%033[0m%]%# ' by strange concindence).
>
> Thanks all for the feedback. I think the new bikeshed colour looks good.
Please find attached some polka dots for the bike shed :)
Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778
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Consider donating to Postgres: http://www.postgresql.org/about/donate
>From fdbb6272338ed71f8cecf2a755ef53b037acc251 Mon Sep 17 00:00:00 2001
From: David Fetter <david.fet...@onelogin.com>
Date: Tue, 19 Nov 2019 11:39:47 -0800
Subject: [PATCH v1] Make visible_length() available to the rest of psql
To: hackers
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="------------2.23.0"
This is a multi-part message in MIME format.
--------------2.23.0
Content-Type: text/plain; charset=UTF-8; format=fixed
Content-Transfer-Encoding: 8bit
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index 90f6380170..3245f3ebae 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -2443,3 +2443,50 @@ recognized_connection_string(const char *connstr)
{
return uri_prefix_length(connstr) != 0 || strchr(connstr, '=') != NULL;
}
+
+/*
+ * Return visible width of the string
+ */
+int
+visible_length(char *string)
+{
+ int visible_length = 0;
+ char *p = string;
+ char *end = p + strlen(p);
+ bool visible = true;
+
+ while(*string)
+ {
+#if defined(USE_READLINE) && defined(RL_PROMPT_START_IGNORE)
+ if (*string == RL_PROMPT_START_IGNORE)
+ {
+ visible = false;
+ ++p;
+ }
+ else if (*p == RL_PROMPT_END_IGNORE)
+ {
+ visible = true;
+ ++p;
+ }
+ else
+#endif
+ {
+ int chlen,
+ chwidth;
+
+ chlen = PQmblen(p, pset.encoding);
+ if (p + chlen > end)
+ break;
+
+ if (visible)
+ {
+ chwidth = PQdsplen(p, pset.encoding);
+ if (chwidth > 0)
+ visible_length += chwidth;
+ }
+
+ p += chlen;
+ }
+ }
+ return visible_length;
+}
diff --git a/src/bin/psql/common.h b/src/bin/psql/common.h
index 282a520116..56e28915ce 100644
--- a/src/bin/psql/common.h
+++ b/src/bin/psql/common.h
@@ -44,4 +44,5 @@ extern void expand_tilde(char **filename);
extern bool recognized_connection_string(const char *connstr);
+extern int visible_length(char *string);
#endif /* COMMON_H */
diff --git a/src/bin/psql/prompt.c b/src/bin/psql/prompt.c
index 41c6f21ecf..9c0e2c7567 100644
--- a/src/bin/psql/prompt.c
+++ b/src/bin/psql/prompt.c
@@ -347,46 +347,7 @@ get_prompt(promptStatus_t status, ConditionalStack cstack)
/* Compute the visible width of PROMPT1, for PROMPT2's %w */
if (prompt_string == pset.prompt1)
- {
- char *p = destination;
- char *end = p + strlen(p);
- bool visible = true;
-
- last_prompt1_width = 0;
- while (*p)
- {
-#if defined(USE_READLINE) && defined(RL_PROMPT_START_IGNORE)
- if (*p == RL_PROMPT_START_IGNORE)
- {
- visible = false;
- ++p;
- }
- else if (*p == RL_PROMPT_END_IGNORE)
- {
- visible = true;
- ++p;
- }
- else
-#endif
- {
- int chlen,
- chwidth;
-
- chlen = PQmblen(p, pset.encoding);
- if (p + chlen > end)
- break; /* Invalid string */
-
- if (visible)
- {
- chwidth = PQdsplen(p, pset.encoding);
- if (chwidth > 0)
- last_prompt1_width += chwidth;
- }
-
- p += chlen;
- }
- }
- }
+ last_prompt1_width = visible_length(destination);
return destination;
}
--------------2.23.0--
