libsmartcols: cleanup scols_table_set_symbols() API

Change behavior:
  * scols_table_set_symbols(tb, NULL) remove reference to the current symbols setting
    and does not set default symbols at all

Add new functions:
  * scols_table_get_symbols()
  * scols_table_set_default_symbols()

Signed-off-by: Karel Zak <kzak@redhat.com>

6 files changed, 103 insertions, 34 deletions

diff --git a/libsmartcols/docs/libsmartcols-sections.txt b/libsmartcols/docs/libsmartcols-sections.txt
index 324f6e15f..ccda20196 100644
--- a/libsmartcols/docs/libsmartcols-sections.txt
+++ b/libsmartcols/docs/libsmartcols-sections.txt
@@ -116,6 +116,7 @@ scols_table_get_line_separator
 scols_table_get_ncols
 scols_table_get_nlines
 scols_table_get_stream
+scols_table_get_symbols
 scols_table_get_termforce
 scols_table_get_termwidth
 scols_table_get_title
@@ -137,6 +138,7 @@ scols_table_remove_columns
 scols_table_remove_line
 scols_table_remove_lines
 scols_table_set_column_separator
+scols_table_set_default_symbols
 scols_table_set_line_separator
 scols_table_set_name
 scols_table_set_stream
diff --git a/libsmartcols/src/libsmartcols.h.in b/libsmartcols/src/libsmartcols.h.in
index de2f271cf..02c691160 100644
--- a/libsmartcols/src/libsmartcols.h.in
+++ b/libsmartcols/src/libsmartcols.h.in
@@ -239,6 +239,8 @@ extern struct libscols_line *scols_table_new_line(struct libscols_table *tb, str
 extern struct libscols_line *scols_table_get_line(struct libscols_table *tb, size_t n);
 extern struct libscols_table *scols_copy_table(struct libscols_table *tb);
 extern int scols_table_set_symbols(struct libscols_table *tb, struct libscols_symbols *sy);
+extern int scols_table_set_default_symbols(struct libscols_table *tb);
+extern struct libscols_symbols *scols_table_get_symbols(const struct libscols_table *tb);
 
 extern int scols_table_set_stream(struct libscols_table *tb, FILE *stream);
 extern FILE *scols_table_get_stream(const struct libscols_table *tb);
diff --git a/libsmartcols/src/libsmartcols.sym b/libsmartcols/src/libsmartcols.sym
index d599a5030..62698bac6 100644
--- a/libsmartcols/src/libsmartcols.sym
+++ b/libsmartcols/src/libsmartcols.sym
@@ -141,8 +141,10 @@ SMARTCOLS_2.29 {
 global:
 	scols_column_is_wrapnl;
 	scols_symbols_set_cell_padding;
+	scols_table_get_symbols;
 	scols_table_get_termforce;
 	scols_table_get_termwidth;
+	scols_table_set_default_symbols;
 	scols_table_set_termforce;
 	scols_table_set_termwidth;
 } SMARTCOLS_2.28;
diff --git a/libsmartcols/src/smartcolsP.h b/libsmartcols/src/smartcolsP.h
index ca6ea1be7..8e8bd768e 100644
--- a/libsmartcols/src/smartcolsP.h
+++ b/libsmartcols/src/smartcolsP.h
@@ -161,6 +161,7 @@ struct libscols_table {
 			padding_debug	:1,	/* output visible padding chars */
 			maxout		:1,	/* maximize output */
 			header_printed  :1,	/* header already printed */
+			priv_symbols	:1,	/* default private symbols */
 			no_headings	:1,	/* don't print header */
 			no_linesep	:1,	/* don't print line separator */
 			no_wrap		:1;	/* never wrap lines */
diff --git a/libsmartcols/src/table.c b/libsmartcols/src/table.c
index fcb53b64a..a433e42b4 100644
--- a/libsmartcols/src/table.c
+++ b/libsmartcols/src/table.c
@@ -667,14 +667,62 @@ err:
 }
 
 /**
+ * scols_table_set_default_symbols:
+ * @tb: table
+ *
+ * The library check the current environment to select ASCII or UTF8 symbols.
+ * This default behavior could be controlled by scols_table_enable_ascii().
+ *
+ * Use scols_table_set_symbols() to unset symbols or use your own setting.
+ *
+ * Returns: 0, a negative value in case of an error.
+ */
+int scols_table_set_default_symbols(struct libscols_table *tb)
+{
+	struct libscols_symbols *sy;
+	int rc;
+
+	if (!tb)
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "setting default symbols"));
+
+	sy = scols_new_symbols();
+	if (!sy)
+		return -ENOMEM;
+
+#if defined(HAVE_WIDECHAR)
+	if (!scols_table_is_ascii(tb) &&
+	    !strcmp(nl_langinfo(CODESET), "UTF-8")) {
+		scols_symbols_set_branch(sy, UTF_VR UTF_H);
+		scols_symbols_set_vertical(sy, UTF_V " ");
+		scols_symbols_set_right(sy, UTF_UR UTF_H);
+	} else
+#endif
+	{
+		scols_symbols_set_branch(sy, "|-");
+		scols_symbols_set_vertical(sy, "| ");
+		scols_symbols_set_right(sy, "`-");
+	}
+	scols_symbols_set_title_padding(sy, " ");
+	scols_symbols_set_cell_padding(sy, " ");
+
+	rc = scols_table_set_symbols(tb, sy);
+	scols_unref_symbols(sy);
+	return rc;
+}
+
+
+/**
  * scols_table_set_symbols:
  * @tb: table
  * @sy: symbols or NULL
  *
  * Add a reference to @sy from the table. The symbols are used by library to
- * draw tree output. If no symbols are specified then library checks the
- * current environment to select ASCII or UTF8 symbols. This default behavior
- * could be controlled by scols_table_enable_ascii().
+ * draw tree output. If no symbols are used for the table then library creates
+ * default temporary symbols to draw output by scols_table_set_default_symbols().
+ *
+ * If @sy is NULL then remove reference from the currenly uses symbols.
  *
  * Returns: 0, a negative value in case of an error.
  */
@@ -684,38 +732,34 @@ int scols_table_set_symbols(struct libscols_table *tb,
 	if (!tb)
 		return -EINVAL;
 
-	DBG(TAB, ul_debugobj(tb, "setting alternative symbols %p", sy));
-
-	if (tb->symbols)				/* unref old */
+	/* remove old */
+	if (tb->symbols) {
+		DBG(TAB, ul_debugobj(tb, "remove symbols %p refrence", tb->symbols));
 		scols_unref_symbols(tb->symbols);
+		tb->symbols = NULL;
+	}
+
+	/* set new */
 	if (sy) {					/* ref user defined */
+		DBG(TAB, ul_debugobj(tb, "set symbols so %p", sy));
 		tb->symbols = sy;
 		scols_ref_symbols(sy);
-	} else {					/* default symbols */
-		tb->symbols = scols_new_symbols();
-		if (!tb->symbols)
-			return -ENOMEM;
-#if defined(HAVE_WIDECHAR)
-		if (!scols_table_is_ascii(tb) &&
-		    !strcmp(nl_langinfo(CODESET), "UTF-8")) {
-			scols_symbols_set_branch(tb->symbols, UTF_VR UTF_H);
-			scols_symbols_set_vertical(tb->symbols, UTF_V " ");
-			scols_symbols_set_right(tb->symbols, UTF_UR UTF_H);
-		} else
-#endif
-		{
-			scols_symbols_set_branch(tb->symbols, "|-");
-			scols_symbols_set_vertical(tb->symbols, "| ");
-			scols_symbols_set_right(tb->symbols, "`-");
-		}
-		scols_symbols_set_title_padding(tb->symbols, " ");
-		scols_symbols_set_cell_padding(tb->symbols, " ");
 	}
-
 	return 0;
 }
 
 /**
+ * scols_table_get_symbols:
+ * @tb: table
+ *
+ * Returns: pointer to symbols table.
+ */
+struct libscols_symbols *scols_table_get_symbols(const struct libscols_table *tb)
+{
+	return tb->symbols;
+}
+
+/**
  * scols_table_enable_nolinesep
  * @tb: table
  * @enable: 1 or 0
diff --git a/libsmartcols/src/table_print.c b/libsmartcols/src/table_print.c
index 7612682cd..5771111b3 100644
--- a/libsmartcols/src/table_print.c
+++ b/libsmartcols/src/table_print.c
@@ -1339,6 +1339,19 @@ static size_t strlen_line(struct libscols_line *ln)
 	return sz;
 }
 
+static void cleanup_printing(struct libscols_table *tb, struct libscols_buffer *buf)
+{
+	if (!tb)
+		return;
+
+	free_buffer(buf);
+
+	if (tb->priv_symbols) {
+		scols_table_set_symbols(tb, NULL);
+		tb->priv_symbols = 0;
+	}
+}
+
 static int initialize_printing(struct libscols_table *tb, struct libscols_buffer **buf)
 {
 	size_t bufsz, extra_bufsz = 0;
@@ -1348,8 +1361,11 @@ static int initialize_printing(struct libscols_table *tb, struct libscols_buffer
 
 	DBG(TAB, ul_debugobj(tb, "initialize printing"));
 
-	if (!tb->symbols)
-		scols_table_set_symbols(tb, NULL);	/* use default */
+	if (!tb->symbols) {
+		scols_table_set_default_symbols(tb);
+		tb->priv_symbols = 1;
+	} else
+		tb->priv_symbols = 0;
 
 	if (tb->format == SCOLS_FMT_HUMAN)
 		tb->is_term = tb->termforce == SCOLS_TERMFORCE_NEVER  ? 0 :
@@ -1414,8 +1430,10 @@ static int initialize_printing(struct libscols_table *tb, struct libscols_buffer
 	}
 
 	*buf = new_buffer(bufsz + 1);	/* data + space for \0 */
-	if (!*buf)
-		return -ENOMEM;
+	if (!*buf) {
+		rc = -ENOMEM;
+		goto err;
+	}
 
 	if (tb->format == SCOLS_FMT_HUMAN) {
 		rc = recount_widths(tb, *buf);
@@ -1425,7 +1443,7 @@ static int initialize_printing(struct libscols_table *tb, struct libscols_buffer
 
 	return 0;
 err:
-	free_buffer(*buf);
+	cleanup_printing(tb, *buf);
 	return rc;
 }
 
@@ -1436,7 +1454,7 @@ err:
  * @end: last printed line or NULL to print all from start.
  *
  * If the start is the first line in the table than prints table header too.
- * The header is printed only once.
+ * The header is printed only once. This does not work for trees.
  *
  * Returns: 0, a negative value in case of an error.
  */
@@ -1472,7 +1490,7 @@ int scols_table_print_range(	struct libscols_table *tb,
 
 	rc = print_range(tb, buf, &itr, end);
 done:
-	free_buffer(buf);
+	cleanup_printing(tb, buf);
 	return rc;
 }
 
@@ -1564,7 +1582,7 @@ static int __scols_print_table(struct libscols_table *tb, int *is_empty)
 
 	fput_table_close(tb);
 done:
-	free_buffer(buf);
+	cleanup_printing(tb, buf);
 	return rc;
 }