psql: Let \l accept a pattern

reviewed by Satoshi Nagayasu

doc/src/sgml/ref/psql-ref.sgml

@@ -1745,12 +1745,13 @@ hello 10
 
 
       <varlistentry>
-        <term><literal>\l</literal> (or <literal>\list</literal>)</term>
-        <term><literal>\l+</literal> (or <literal>\list+</literal>)</term>
+        <term><literal>\l[+]</literal> or <literal>\list[+] [ <link linkend="APP-PSQL-patterns"><replaceable class="parameter">pattern</replaceable></link> ]</literal></term>
         <listitem>
         <para>
-        List the names, owners, character set encodings, and access privileges
-        of all the databases in the server.
+        List the databases in the server and show their names, owners,
+        character set encodings, and access privileges.
+        If <replaceable class="parameter">pattern</replaceable> is specified,
+        only databases whose names match the pattern are listed.
         If <literal>+</literal> is appended to the command name, database
         sizes, default tablespaces, and descriptions are also displayed.
         (Size information is only available for databases that the current

src/bin/psql/command.c

@@ -821,10 +821,22 @@ exec_command(const char *cmd,
 	}
 
 	/* \l is list databases */
-	else if (strcmp(cmd, "l") == 0 || strcmp(cmd, "list") == 0)
-		success = listAllDbs(false);
-	else if (strcmp(cmd, "l+") == 0 || strcmp(cmd, "list+") == 0)
-		success = listAllDbs(true);
+	else if (strcmp(cmd, "l") == 0 || strcmp(cmd, "list") == 0 ||
+			 strcmp(cmd, "l+") == 0 || strcmp(cmd, "list+") == 0)
+	{
+		char	   *pattern;
+		bool		show_verbose;
+
+		pattern = psql_scan_slash_option(scan_state,
+										 OT_NORMAL, NULL, true);
+
+		show_verbose = strchr(cmd, '+') ? true : false;
+
+		success = listAllDbs(pattern, show_verbose);
+
+		if (pattern)
+			free(pattern);
+	}
 
 	/*
 	 * large object things

src/bin/psql/describe.c

@@ -641,7 +641,7 @@ describeOperators(const char *pattern, bool showSystem)
  * for \l, \list, and -l switch
  */
 bool
-listAllDbs(bool verbose)
+listAllDbs(const char *pattern, bool verbose)
 {
 	PGresult   *res;
 	PQExpBufferData buf;
@@ -684,6 +684,11 @@ listAllDbs(bool verbose)
 	if (verbose && pset.sversion >= 80000)
 		appendPQExpBuffer(&buf,
 		   "  JOIN pg_catalog.pg_tablespace t on d.dattablespace = t.oid\n");
+
+	if (pattern)
+		processSQLNamePattern(pset.db, &buf, pattern, false, false,
+							  NULL, "d.datname", NULL, NULL);
+
 	appendPQExpBuffer(&buf, "ORDER BY 1;");
 	res = PSQLexec(buf.data, false);
 	termPQExpBuffer(&buf);

src/bin/psql/describe.h

@@ -55,7 +55,7 @@ extern bool listTSDictionaries(const char *pattern, bool verbose);
 extern bool listTSTemplates(const char *pattern, bool verbose);
 
 /* \l */
-extern bool listAllDbs(bool verbose);
+extern bool listAllDbs(const char *pattern, bool verbose);
 
 /* \dt, \di, \ds, \dS, etc. */
 extern bool listTables(const char *tabtypes, const char *pattern, bool verbose, bool showSystem);

src/bin/psql/help.c

@@ -235,7 +235,7 @@ slashUsage(unsigned short int pager)
 	fprintf(output, _("  \\dE[S+] [PATTERN]      list foreign tables\n"));
 	fprintf(output, _("  \\dx[+]  [PATTERN]      list extensions\n"));
 	fprintf(output, _("  \\dy     [PATTERN]      list event triggers\n"));
-	fprintf(output, _("  \\l[+]                  list all databases\n"));
+	fprintf(output, _("  \\l[+]   [PATTERN]      list databases\n"));
 	fprintf(output, _("  \\sf[+] FUNCNAME        show a function's definition\n"));
 	fprintf(output, _("  \\z      [PATTERN]      same as \\dp\n"));
 	fprintf(output, "\n");

src/bin/psql/startup.c

@@ -260,7 +260,7 @@ main(int argc, char *argv[])
 		if (!options.no_psqlrc)
 			process_psqlrc(argv[0]);
 
-		success = listAllDbs(false);
+		success = listAllDbs(NULL, false);
 		PQfinish(pset.db);
 		exit(success ? EXIT_SUCCESS : EXIT_FAILURE);
 	}