From: Olivier Matz <zer0@droids-corp.org>
Date: Fri, 11 Mar 2011 19:40:27 +0000 (+0100)
Subject: rdline: add a pager that can be used by user-defined commands
X-Git-Url: http://git.droids-corp.org/?p=libcmdline.git;a=commitdiff_plain;h=3e6cc1d7b682f75a75034602f003c3e9f8a8d3ad

rdline: add a pager that can be used by user-defined commands

Signed-off-by: Olivier Matz <zer0@droids-corp.org>
---

diff --git a/src/lib/cmdline_rdline.c b/src/lib/cmdline_rdline.c
index 7f34946..16fda43 100644
--- a/src/lib/cmdline_rdline.c
+++ b/src/lib/cmdline_rdline.c
@@ -77,6 +77,11 @@ static void rdline_remove_first_history_item(struct rdline *rdl);
 static unsigned int rdline_get_history_size(struct rdline *rdl);
 #endif /* !NO_RDLINE_HISTORY */
 
+#ifndef NO_PAGER
+static int rdline_pager_next_page(struct rdline *rdl);
+static void rdline_asyncpager_reset(struct rdline *rdl);
+#endif /* !NO_PAGER */
+
 
 /* isblank() needs _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE, so use our
  * own. */
@@ -206,6 +211,28 @@ rdline_parse_char(struct rdline *rdl, char c)
 	if (cmd == VT100_NOT_COMPLETE)
 		return RDLINE_RES_SUCCESS;
 
+#ifndef NO_PAGER
+	/* display asynchrounous printf if any */
+	if (rdl->pager_buf != NULL) {
+		if (cmd == VT100_STD_CHAR && c == 'q') {
+			rdline_asyncpager_reset(rdl);
+			// call cb()
+			if (rdl->pager_buf == NULL)
+				return RDLINE_RES_VALIDATED;
+		}
+
+		if (rdline_pager_next_page(rdl) == 0) {
+			rdline_asyncpager_reset(rdl);
+			// call cb()
+			if (rdl->pager_buf == NULL)
+				return RDLINE_RES_VALIDATED;
+		}
+		/* async printf was called in cb() */
+		return RDLINE_RES_SUCCESS;
+	}
+#endif
+
+	/* process control chars */
 	if (cmd != VT100_STD_CHAR) {
 		switch (cmd) {
 		case CMDLINE_KEY_CTRL_B:
@@ -368,6 +395,12 @@ rdline_parse_char(struct rdline *rdl, char c)
 			rdl->left_buf[CIRBUF_GET_LEN(&rdl->left)] = '\0';
 			rdline_printf(rdl, "\r\n");
 			rdl->help(rdl, rdl->left_buf, rdline_write, rdl);
+#ifndef NO_PAGER
+			if (rdl->pager_buf != NULL) {
+				// XXX set cb
+				return RDLINE_RES_SUCCESS;
+			}
+#endif
 			rdline_redisplay(rdl);
 			break;
 		}
@@ -393,6 +426,12 @@ rdline_parse_char(struct rdline *rdl, char c)
 				rdl->left_buf[CIRBUF_GET_LEN(&rdl->left)] = '\0';
 				rdline_printf(rdl, "\r\n");
 				rdl->help(rdl, rdl->left_buf, rdline_write, rdl);
+#ifndef NO_PAGER
+				if (rdl->pager_buf != NULL) {
+					// XXX set cb
+					return RDLINE_RES_SUCCESS;
+				}
+#endif
 				rdline_redisplay(rdl);
 				break;
 			}
@@ -416,7 +455,6 @@ rdline_parse_char(struct rdline *rdl, char c)
 			cirbuf_align_left(&rdl->left);
 			rdl->left_buf[CIRBUF_GET_LEN(&rdl->left)] = '\n';
 			rdl->left_buf[CIRBUF_GET_LEN(&rdl->left) + 1] = '\0';
-			rdl->status = RDLINE_INIT;
 			rdline_printf(rdl, "\r\n");
 #ifndef NO_RDLINE_HISTORY
 			if (rdl->history_cur_line != -1)
@@ -425,9 +463,21 @@ rdline_parse_char(struct rdline *rdl, char c)
 
 			if (rdl->validate)
 				rdl->validate(rdl, rdl->left_buf, CIRBUF_GET_LEN(&rdl->left)+2);
+#ifndef NO_PAGER
 			/* user may have stopped rdline */
+			if (rdl->status == RDLINE_EXITED) {
+				rdline_asyncpager_reset(rdl);
+				return RDLINE_RES_EXITED;
+			}
+			if (rdl->pager_buf != NULL) {
+				// XXX set cb
+				return RDLINE_RES_SUCCESS;
+			}
+			rdl->status = RDLINE_INIT;
+#else
 			if (rdl->status == RDLINE_EXITED)
 				return RDLINE_RES_EXITED;
+#endif
 			return RDLINE_RES_VALIDATED;
 
 #ifndef NO_RDLINE_HISTORY
@@ -704,3 +754,142 @@ rdline_printf(const struct rdline *rdl, const char *fmt, ...)
 
 	return ret;
 }
+
+#ifndef NO_PAGER
+/* reset pager state */
+void
+rdline_asyncpager_reset(struct rdline *rdl)
+{
+	if (rdl->pager_buf) {
+		free(rdl->pager_buf);
+		rdl->pager_buf = NULL;
+	}
+	rdl->pager_lines = 0;
+	rdl->pager_len = 0;
+	rdl->pager_off = 0;
+}
+
+/* Return the offset of the i-th occurence of char c in string s. If
+ * there is less than i occurences, return -1 and fill i with the
+ * count. */
+static int
+strnchr(const char *s, char c, int *i)
+{
+	int n = 0;
+	const char *orig = s;
+
+	while (*s) {
+		if (*s == c)
+			n++;
+		if (*i == n)
+			return s - orig;
+		s++;
+	}
+	*i = n;
+	return -1;
+}
+
+/* display a page of data from pager, return 0 if all is displayed */
+static int
+rdline_pager_next_page(struct rdline *rdl)
+{
+	int lines = RDLINE_MAX_LINES;
+	int displen;
+	char *s;
+
+	s = rdl->pager_buf;
+	if (s == NULL)
+		return 0;
+
+	rdline_printf(rdl, vt100_home);
+	rdline_printf(rdl, vt100_clear_right);
+
+	s += rdl->pager_off;
+
+	/* we know that s is 0-terminated */
+	displen = strnchr(s, '\n', &lines);
+	rdl->pager_lines = lines;
+
+	/* we can display all the data */
+	if (displen == -1) {
+		write(rdl->fd_out, s, rdl->pager_len);
+		free(rdl->pager_buf);
+		rdl->pager_buf = NULL;
+		return 0;
+	}
+
+	displen = displen + 1; /* include \n */
+	write(rdl->fd_out, s, displen);
+	rdl->pager_off += displen;
+	rdl->pager_len -= displen;
+
+	rdline_printf(rdl, "--- press a key to continue ---");
+	return -1;
+}
+
+/* push data in pager */
+static int
+rdline_pager_push(struct rdline *rdl, char *s, int len)
+{
+	/* display as many lines as we can */
+	if (rdl->pager_lines < RDLINE_MAX_LINES) {
+		int lines = RDLINE_MAX_LINES - rdl->pager_lines;
+		int displen;
+
+		/* we know that s is 0-terminated */
+		displen = strnchr(s, '\n', &lines);
+		rdl->pager_lines += lines;
+
+		/* we can display all the data */
+		if (displen == -1) {
+			write(rdl->fd_out, s, len);
+			return 0;
+		}
+		displen = displen + 1; /* include \n */
+		write(rdl->fd_out, s, displen);
+		s += displen;
+		len -= displen;
+	}
+
+	if (rdl->pager_buf == NULL) {
+		rdline_printf(rdl, "--- press a key to continue ---");
+	}
+	rdl->pager_buf = realloc(rdl->pager_buf, rdl->pager_len + len);
+	if (rdl->pager_buf == NULL) {
+		rdline_asyncpager_reset(rdl);
+		return -1;
+	}
+
+	memcpy(rdl->pager_buf + rdl->pager_len, s, len);
+	rdl->pager_len += len;
+	return 0;
+}
+
+/* XXX we should have a specific return value when displaying will be
+ * asynchronous, we may also have a callback */
+int
+rdline_asyncpager_printf(struct rdline *rdl, const char *fmt, ...)
+{
+	int n;
+	char *buf;
+	va_list ap;
+
+	if (rdl->fd_out < 0)
+		return -1;
+
+	buf = malloc(BUFSIZ);
+	if (buf == NULL)
+		return -1;
+
+	va_start(ap, fmt);
+	n = vsnprintf(buf, BUFSIZ, fmt, ap);
+	va_end(ap);
+
+	if (n >= BUFSIZ)
+		n = BUFSIZ-1;
+	if (n > 0)
+		rdline_pager_push(rdl, buf, n);
+	free(buf);
+	return n;
+}
+#endif /* !NO_PAGER */
diff --git a/src/lib/cmdline_rdline.h b/src/lib/cmdline_rdline.h
index cee438a..23b8cb6 100644
--- a/src/lib/cmdline_rdline.h
+++ b/src/lib/cmdline_rdline.h
@@ -147,6 +147,13 @@ struct rdline {
 
 	/* opaque pointer */
 	void *opaque;
+
+#ifndef NO_PAGER
+	char *pager_buf; /* buffer used to store paged data */
+	int pager_len; /* total len of buffer */
+	int pager_off; /* offset of next data */
+	int pager_lines; /* number of lines displayed */
+#endif
 };
 
 /**
@@ -351,4 +358,26 @@ void rdline_clear_history(struct rdline *rdl);
  */
 char *rdline_get_history_item(struct rdline *rdl, unsigned int i);
 
+#ifndef NO_PAGER
+/**
+ * Print data asynchronously (using pager if needed)
+ *
+ * If there is enough place to print data on the current page, it is
+ * printed synchronously. Else, a temporary buffer is allocated and
+ * the data is stored in it. When the main rdline is called again, the
+ * pager is flushed before parsing any other commands.
+ *
+ * @param rdl
+ *   The rdline descriptor
+ * @param fmt
+ *   The format strings
+ * @return
+ *   Upon successful return, these functions return the number of
+ *   characters printed (not including the trailing '\0' used to end
+ *   output to strings). On error, a negative value is returned.
+ */
+int rdline_asyncpager_printf(struct rdline *rdl, const char *fmt, ...);
+#endif
+
+
 #endif /* _RDLINE_H_ */