[ovs-dev] [PATCH 1/2] table: Create method for resetting table formatting.

[Mark Michelson]

Table formatting has a local static integer that is intended to insert
line breaks between tables. This works exactly as intended, as long as
each call to table_format() is done as a single unit within the run of a
process.

When ovn-nbctl is run in daemon mode, it is a long-running process that
makes multiple calls to table_format() throughout its lifetime. After
the first call, this results in an unexpected newline prepended to table
output on each subsequent ovn-nbctl invocation.

The solution is to introduce a function to reset table formatting. This
way, the first time after resetting table formatting, no newline is
prepended.

Signed-off-by: Mark Michelson <mmich...@redhat.com>
---
 lib/table.c               | 23 +++++++++++++++++------
 lib/table.h               |  1 +
 ovn/utilities/ovn-nbctl.c |  1 +
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/lib/table.c b/lib/table.c
index ab72668c7..48d18b651 100644
--- a/lib/table.c
+++ b/lib/table.c
@@ -236,15 +236,18 @@ table_print_timestamp__(const struct table *table, struct 
ds *s)
     }
 }
 
+static bool first_table = true;
+
 static void
 table_print_table__(const struct table *table, const struct table_style *style,
                     struct ds *s)
 {
-    static int n = 0;
     int *widths;
     size_t x, y;
 
-    if (n++ > 0) {
+    if (first_table) {
+        first_table = false;
+    } else {
         ds_put_char(s, '\n');
     }
 
@@ -318,10 +321,11 @@ static void
 table_print_list__(const struct table *table, const struct table_style *style,
                    struct ds *s)
 {
-    static int n = 0;
     size_t x, y;
 
-    if (n++ > 0) {
+    if (first_table) {
+        first_table = false;
+    } else {
         ds_put_char(s, '\n');
     }
 
@@ -469,10 +473,11 @@ static void
 table_print_csv__(const struct table *table, const struct table_style *style,
                   struct ds *s)
 {
-    static int n = 0;
     size_t x, y;
 
-    if (n++ > 0) {
+    if (first_table) {
+        first_table = false;
+    } else {
         ds_put_char(s, '\n');
     }
 
@@ -614,6 +619,12 @@ table_format(const struct table *table, const struct 
table_style *style,
     }
 }
 
+void
+table_format_reset(void)
+{
+    first_table = true;
+}
+
 /* Outputs 'table' on stdout in the specified 'style'. */
 void
 table_print(const struct table *table, const struct table_style *style)
diff --git a/lib/table.h b/lib/table.h
index 76e65bb70..33263e2a2 100644
--- a/lib/table.h
+++ b/lib/table.h
@@ -133,6 +133,7 @@ void table_parse_cell_format(struct table_style *, const 
char *format);
 void table_print(const struct table *, const struct table_style *);
 void table_format(const struct table *, const struct table_style *,
                   struct ds *);
+void table_format_reset(void);
 void table_usage(void);
 
 #endif /* table.h */
diff --git a/ovn/utilities/ovn-nbctl.c b/ovn/utilities/ovn-nbctl.c
index eabd30308..d65a9ba08 100644
--- a/ovn/utilities/ovn-nbctl.c
+++ b/ovn/utilities/ovn-nbctl.c
@@ -5311,6 +5311,7 @@ server_cmd_run(struct unixctl_conn *conn, int argc, const 
char **argv_,
     }
 
     struct ds output = DS_EMPTY_INITIALIZER;
+    table_format_reset();
     for (struct ctl_command *c = commands; c < &commands[n_commands]; c++) {
         if (c->table) {
             table_format(c->table, &table_style, &output);
-- 
2.14.4

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