libsmartcols: add JSON output format

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

6 files changed, 242 insertions, 24 deletions

diff --git a/libsmartcols/docs/libsmartcols-sections.txt b/libsmartcols/docs/libsmartcols-sections.txt
index 2b8180c52..01bc2a63c 100644
--- a/libsmartcols/docs/libsmartcols-sections.txt
+++ b/libsmartcols/docs/libsmartcols-sections.txt
@@ -93,6 +93,7 @@ scols_table_colors_wanted
 scols_table_enable_ascii
 scols_table_enable_colors
 scols_table_enable_export
+scols_table_enable_json
 scols_table_enable_maxout
 scols_table_enable_noheadings
 scols_table_enable_raw
@@ -106,6 +107,7 @@ scols_table_get_stream
 scols_table_is_ascii
 scols_table_is_empty
 scols_table_is_export
+scols_table_is_json
 scols_table_is_maxout
 scols_table_is_noheadings
 scols_table_is_raw
@@ -121,6 +123,7 @@ scols_table_remove_line
 scols_table_remove_lines
 scols_table_set_column_separator
 scols_table_set_line_separator
+scols_table_set_name
 scols_table_set_stream
 scols_table_set_symbols
 scols_sort_table
diff --git a/libsmartcols/src/libsmartcols.h.in b/libsmartcols/src/libsmartcols.h.in
index e61256022..d2a88c9cd 100644
--- a/libsmartcols/src/libsmartcols.h.in
+++ b/libsmartcols/src/libsmartcols.h.in
@@ -172,8 +172,10 @@ extern struct libscols_line *scols_copy_line(struct libscols_line *ln);
 
 /* table */
 extern int scols_table_colors_wanted(struct libscols_table *tb);
+extern int scols_table_set_name(struct libscols_table *tb, const char *name);
 extern int scols_table_is_raw(struct libscols_table *tb);
 extern int scols_table_is_ascii(struct libscols_table *tb);
+extern int scols_table_is_json(struct libscols_table *tb);
 extern int scols_table_is_noheadings(struct libscols_table *tb);
 extern int scols_table_is_empty(struct libscols_table *tb);
 extern int scols_table_is_export(struct libscols_table *tb);
@@ -183,6 +185,7 @@ extern int scols_table_is_tree(struct libscols_table *tb);
 extern int scols_table_enable_colors(struct libscols_table *tb, int enable);
 extern int scols_table_enable_raw(struct libscols_table *tb, int enable);
 extern int scols_table_enable_ascii(struct libscols_table *tb, int enable);
+extern int scols_table_enable_json(struct libscols_table *tb, int enable);
 extern int scols_table_enable_noheadings(struct libscols_table *tb, int enable);
 extern int scols_table_enable_export(struct libscols_table *tb, int enable);
 extern int scols_table_enable_maxout(struct libscols_table *tb, int enable);
diff --git a/libsmartcols/src/libsmartcols.sym b/libsmartcols/src/libsmartcols.sym
index 2629213c1..0ef3322b3 100644
--- a/libsmartcols/src/libsmartcols.sym
+++ b/libsmartcols/src/libsmartcols.sym
@@ -1,7 +1,7 @@
 /*
  * symbols since util-linux 2.25
  *
- * Copyright (C) 2014 Karel Zak <kzak@redhat.com>
+ * Copyright (C) 2014-2015 Karel Zak <kzak@redhat.com>
  */
 SMARTCOLS_2.25 {
 global:
@@ -112,3 +112,11 @@ global:
 local:
 	*;
 };
+
+
+SMARTCOLS_2.27 {
+global:
+	scols_table_enable_json;
+	scols_table_is_json;
+	scols_table_set_name;
+} SMARTCOLS_2.25;
diff --git a/libsmartcols/src/smartcolsP.h b/libsmartcols/src/smartcolsP.h
index 511b182a2..c4fe725d0 100644
--- a/libsmartcols/src/smartcolsP.h
+++ b/libsmartcols/src/smartcolsP.h
@@ -122,7 +122,8 @@ struct libscols_line {
 enum {
 	SCOLS_FMT_HUMAN = 0,		/* default, human readable */
 	SCOLS_FMT_RAW,			/* space separated */
-	SCOLS_FMT_EXPORT		/* COLNAME="data" ... */
+	SCOLS_FMT_EXPORT,		/* COLNAME="data" ... */
+	SCOLS_FMT_JSON			/* http://en.wikipedia.org/wiki/JSON */
 };
 
 /*
@@ -130,6 +131,7 @@ enum {
  */
 struct libscols_table {
 	int	refcount;
+	char	*name;		/* optional table table */
 	size_t	ncols;		/* number of columns */
 	size_t  ntreecols;	/* number of columns with SCOLS_FL_TREE */
 	size_t	nlines;		/* number of lines */
@@ -144,6 +146,8 @@ struct libscols_table {
 	struct list_head	tb_lines;
 	struct libscols_symbols	*symbols;
 
+	int	indent;		/* indention counter */
+	int	indent_last_sep;/* last printed has been line separator */
 	int	format;		/* SCOLS_FMT_* */
 
 	/* flags */
@@ -171,4 +175,13 @@ struct libscols_table {
 				(itr)->p->next : (itr)->p->prev; \
 	} while(0)
 
+
+static inline int scols_iter_is_last(struct libscols_iter *itr)
+{
+	if (!itr || !itr->head || !itr->p)
+		return 0;
+
+	return itr->p == itr->head;
+}
+
 #endif /* _LIBSMARTCOLS_PRIVATE_H */
diff --git a/libsmartcols/src/table.c b/libsmartcols/src/table.c
index 45d6a309c..a42ae514d 100644
--- a/libsmartcols/src/table.c
+++ b/libsmartcols/src/table.c
@@ -89,10 +89,38 @@ void scols_unref_table(struct libscols_table *tb)
 		scols_unref_symbols(tb->symbols);
 		free(tb->linesep);
 		free(tb->colsep);
+		free(tb->name);
 		free(tb);
 	}
 }
 
+
+/**
+ * scols_table_set_name:
+ * @tb: a pointer to a struct libscols_table instance
+ * @name: a name
+ *
+ * The table name is used for example for JSON top level object name.
+ *
+ * Returns: 0, a negative number in case of an error.
+ */
+int scols_table_set_name(struct libscols_table *tb, const char *name)
+{
+	char *p = NULL;
+
+	if (!tb)
+		return -EINVAL;
+
+	if (name) {
+		p = strdup(name);
+		if (!p)
+			return -ENOMEM;
+	}
+	free(tb->name);
+	tb->name = p;
+	return 0;
+}
+
 /**
  * scols_table_add_column:
  * @tb: a pointer to a struct libscols_table instance
@@ -659,6 +687,7 @@ int scols_table_set_symbols(struct libscols_table *tb,
 
 	return 0;
 }
+
 /**
  * scols_table_enable_colors:
  * @tb: table
@@ -677,13 +706,14 @@ int scols_table_enable_colors(struct libscols_table *tb, int enable)
 	tb->colors_wanted = enable;
 	return 0;
 }
+
 /**
  * scols_table_enable_raw:
  * @tb: table
  * @enable: 1 or 0
  *
  * Enable/disable raw output format. The parsable output formats
- * (export and raw) are mutually exclusive.
+ * (export, raw, JSON, ...) are mutually exclusive.
  *
  * Returns: 0 on success, negative number in case of an error.
  */
@@ -701,6 +731,29 @@ int scols_table_enable_raw(struct libscols_table *tb, int enable)
 }
 
 /**
+ * scols_table_enable_json:
+ * @tb: table
+ * @enable: 1 or 0
+ *
+ * Enable/disable JSON output format. The parsable output formats
+ * (export, raw, JSON, ...) are mutually exclusive.
+ *
+ * Returns: 0 on success, negative number in case of an error.
+ */
+int scols_table_enable_json(struct libscols_table *tb, int enable)
+{
+	if (!tb)
+		return -EINVAL;
+
+	DBG(TAB, ul_debugobj(tb, "json: %s", enable ? "ENABLE" : "DISABLE"));
+	if (enable)
+		tb->format = SCOLS_FMT_JSON;
+	else if (tb->format == SCOLS_FMT_JSON)
+		tb->format = 0;
+	return 0;
+}
+
+/**
  * scols_table_enable_export:
  * @tb: table
  * @enable: 1 or 0
@@ -851,6 +904,17 @@ int scols_table_is_raw(struct libscols_table *tb)
 	return tb && tb->format == SCOLS_FMT_RAW;
 }
 
+/**
+ * scols_table_is_json:
+ * @tb: table
+ *
+ * Returns: 1 if JSON output format is enabled.
+ */
+int scols_table_is_json(struct libscols_table *tb)
+{
+	return tb && tb->format == SCOLS_FMT_JSON;
+}
+
 
 /**
  * scols_table_is_maxout
diff --git a/libsmartcols/src/table_print.c b/libsmartcols/src/table_print.c
index fbca28a1f..37d75c962 100644
--- a/libsmartcols/src/table_print.c
+++ b/libsmartcols/src/table_print.c
@@ -269,21 +269,33 @@ static int print_data(struct libscols_table *tb,
 	if (!data)
 		data = "";
 
-	/* raw mode */
-	if (scols_table_is_raw(tb)) {
+	switch (tb->format) {
+	case SCOLS_FMT_RAW:
 		fputs_nonblank(data, tb->out);
 		if (!is_last_column(tb, cl))
 			fputs(colsep(tb), tb->out);
 		return 0;
-	}
 
-	/* NAME=value mode */
-	if (scols_table_is_export(tb)) {
+	case SCOLS_FMT_EXPORT:
 		fprintf(tb->out, "%s=", scols_cell_get_data(&cl->header));
 		fputs_quoted(data, tb->out);
 		if (!is_last_column(tb, cl))
 			fputs(colsep(tb), tb->out);
 		return 0;
+
+	case SCOLS_FMT_JSON:
+		fputs_quoted(scols_cell_get_data(&cl->header), tb->out);
+		fputs(": ", tb->out);
+		if (!data || !*data)
+			fputs("null", tb->out);
+		else
+			fputs_quoted(data, tb->out);
+		if (!is_last_column(tb, cl))
+			fputs(", ", tb->out);
+		return 0;
+
+	case SCOLS_FMT_HUMAN:
+		break;		/* continue below */
 	}
 
 	if (tb->colors_wanted) {
@@ -384,7 +396,7 @@ static int cell_to_buffer(struct libscols_table *tb,
 	/*
 	 * Tree stuff
 	 */
-	if (ln->parent) {
+	if (ln->parent && !scols_table_is_json(tb)) {
 		rc = line_ascii_art_to_buffer(tb, ln->parent, buf);
 
 		if (!rc && list_entry_is_last(&ln->ln_children, &ln->parent->ln_branch))
@@ -400,6 +412,95 @@ static int cell_to_buffer(struct libscols_table *tb,
 	return rc;
 }
 
+static void fput_indent(struct libscols_table *tb)
+{
+	int i;
+
+	for (i = 0; i <= tb->indent; i++)
+		fputs("   ", tb->out);
+}
+
+static void fput_table_open(struct libscols_table *tb)
+{
+	tb->indent = 0;
+
+	if (scols_table_is_json(tb)) {
+		fputc('{', tb->out);
+		fputs(linesep(tb), tb->out);
+
+		fput_indent(tb);
+		fputs_quoted(tb->name, tb->out);
+		fputs(": [", tb->out);
+		fputs(linesep(tb), tb->out);
+
+		tb->indent++;
+		tb->indent_last_sep = 1;
+	}
+}
+
+static void fput_table_close(struct libscols_table *tb)
+{
+	tb->indent--;
+
+	if (scols_table_is_json(tb)) {
+		fput_indent(tb);
+		fputc(']', tb->out);
+		tb->indent--;
+		fputs(linesep(tb), tb->out);
+		fputc('}', tb->out);
+		fputs(linesep(tb), tb->out);
+		tb->indent_last_sep = 1;
+	}
+}
+
+static void fput_children_open(struct libscols_table *tb)
+{
+	if (scols_table_is_json(tb)) {
+		fputc(',', tb->out);
+		fputs(linesep(tb), tb->out);
+		fput_indent(tb);
+		fputs("\"children\": [", tb->out);
+	}
+	/* between parent and child is separator */
+	fputs(linesep(tb), tb->out);
+	tb->indent_last_sep = 1;
+	tb->indent++;
+}
+
+static void fput_children_close(struct libscols_table *tb)
+{
+	tb->indent--;
+
+	if (scols_table_is_json(tb)) {
+		fput_indent(tb);
+		fputc(']', tb->out);
+		fputs(linesep(tb), tb->out);
+		tb->indent_last_sep = 1;
+	}
+}
+
+static void fput_line_open(struct libscols_table *tb)
+{
+	if (scols_table_is_json(tb)) {
+		fput_indent(tb);
+		fputc('{', tb->out);
+		tb->indent_last_sep = 0;
+	}
+	tb->indent++;
+}
+
+static void fput_line_close(struct libscols_table *tb, int last)
+{
+	tb->indent--;
+	if (scols_table_is_json(tb)) {
+		if (tb->indent_last_sep)
+			fput_indent(tb);
+		fputs(last ? "}" : "},", tb->out);
+	}
+	fputs(linesep(tb), tb->out);
+	tb->indent_last_sep = 1;
+}
+
 /*
  * Prints data. Data can be printed in more formats (raw, NAME=xxx pairs), and
  * control and non-printable characters can be encoded in the \x?? encoding.
@@ -425,8 +526,6 @@ static int print_line(struct libscols_table *tb,
 					buf);
 	}
 
-	if (rc == 0)
-		fputs(linesep(tb), tb->out);
 	return 0;
 }
 
@@ -460,63 +559,82 @@ static int print_header(struct libscols_table *tb, struct libscols_buffer *buf)
 
 static int print_table(struct libscols_table *tb, struct libscols_buffer *buf)
 {
-	int rc;
+	int rc = 0;
 	struct libscols_line *ln;
 	struct libscols_iter itr;
 
 	assert(tb);
 
-	rc = print_header(tb, buf);
-
 	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
-	while (rc == 0 && scols_table_next_line(tb, &itr, &ln) == 0)
+	while (rc == 0 && scols_table_next_line(tb, &itr, &ln) == 0) {
+		fput_line_open(tb);
 		rc = print_line(tb, ln, buf);
+		fput_line_close(tb, scols_iter_is_last(&itr));
+	}
 
 	return rc;
 }
 
 static int print_tree_line(struct libscols_table *tb,
 			   struct libscols_line *ln,
-			   struct libscols_buffer *buf)
+			   struct libscols_buffer *buf,
+			   int last)
 {
 	int rc;
 	struct list_head *p;
 
+	fput_line_open(tb);
+
 	rc = print_line(tb, ln, buf);
 	if (rc)
-		return rc;
-	if (list_empty(&ln->ln_branch))
+		goto done;
+
+	if (list_empty(&ln->ln_branch)) {
+		fput_line_close(tb, last);
 		return 0;
+	}
+
+	fput_children_open(tb);
 
 	/* print all children */
 	list_for_each(p, &ln->ln_branch) {
 		struct libscols_line *chld =
 				list_entry(p, struct libscols_line, ln_children);
-		rc = print_tree_line(tb, chld, buf);
+
+		rc = print_tree_line(tb, chld, buf, p->next == &ln->ln_branch);
 		if (rc)
-			break;
+			goto done;
 	}
 
+	fput_children_close(tb);
+
+	if (scols_table_is_json(tb))
+		fput_line_close(tb, last);
+done:
 	return rc;
 }
 
 static int print_tree(struct libscols_table *tb, struct libscols_buffer *buf)
 {
-	int rc;
-	struct libscols_line *ln;
+	int rc = 0;
+	struct libscols_line *ln, *last = NULL;
 	struct libscols_iter itr;
 
 	assert(tb);
 
 	DBG(TAB, ul_debugobj(tb, "printing tree"));
 
-	rc = print_header(tb, buf);
+	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
+
+	while (scols_table_next_line(tb, &itr, &ln) == 0)
+		if (!last || !ln->parent)
+			last = ln;
 
 	scols_reset_iter(&itr, SCOLS_ITER_FORWARD);
 	while (rc == 0 && scols_table_next_line(tb, &itr, &ln) == 0) {
 		if (ln->parent)
 			continue;
-		rc = print_tree_line(tb, ln, buf);
+		rc = print_tree_line(tb, ln, buf, ln == last);
 	}
 
 	return rc;
@@ -852,11 +970,20 @@ int scols_print_table(struct libscols_table *tb)
 			goto done;
 	}
 
+	fput_table_open(tb);
+
+	if (!scols_table_is_json(tb)) {
+		rc = print_header(tb, buf);
+		if (rc)
+			goto done;
+	}
+
 	if (scols_table_is_tree(tb))
 		rc = print_tree(tb, buf);
 	else
 		rc = print_table(tb, buf);
 
+	fput_table_close(tb);
 done:
 	free_buffer(buf);
 	return rc;