From 8ed252144a29fb6370b828d84419d5c59d23dae2 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Wed, 27 Feb 2019 18:48:36 +0000
Subject: [PATCH] Make 'show width/height' display "unlimited" when capped for
 readline

When we cap the height/width sizes before passing to readline, tweak
the corresponding command variable to show "unlimited":

  (gdb) set height 0x8000
  (gdb) show height
  Number of lines gdb thinks are in a page is unlimited.

Instead of the current output:
  (gdb) set height 0x8000
  (gdb) show height
  Number of lines gdb thinks are in a page is 32768.

gdb/ChangeLog:
2019-02-27  Pedro Alves  <palves@redhat.com>

	* utils.c (set_screen_size): When we cap the height/width sizes,
	tweak the corresponding command variable to show "unlimited":

gdb/testsuite/ChangeLog:
2019-02-27  Pedro Alves  <palves@redhat.com>

	* gdb.base/page.exp: Add tests for "set/show width/height" with
	"infinite" values.
---
 gdb/ChangeLog                   |  5 +++++
 gdb/testsuite/ChangeLog         |  5 +++++
 gdb/testsuite/gdb.base/page.exp | 24 ++++++++++++++++++++++++
 gdb/utils.c                     | 10 ++++++++--
 4 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 02602b2320..1dc6356784 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2019-02-27  Pedro Alves  <palves@redhat.com>
+
+	* utils.c (set_screen_size): When we cap the height/width sizes,
+	tweak the corresponding command variable to show "unlimited":
+
 2019-02-27  Saagar Jha  <saagar@saagarjha.com>
 	    Pedro Alves  <palves@redhat.com>
 
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 477165a0d8..b5177c7e07 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-02-27  Pedro Alves  <palves@redhat.com>
+
+	* gdb.base/page.exp: Add tests for "set/show width/height" with
+	"infinite" values.
+
 2019-02-27  Tom Tromey  <tromey@adacore.com>
 
 	* lib/gdb.exp (skip_python_tests_prompt): Don't check for Python
diff --git a/gdb/testsuite/gdb.base/page.exp b/gdb/testsuite/gdb.base/page.exp
index 10ebf0d43b..8f1698c26e 100644
--- a/gdb/testsuite/gdb.base/page.exp
+++ b/gdb/testsuite/gdb.base/page.exp
@@ -94,6 +94,30 @@ gdb_expect_list "paged count for interrupt" \
 
 gdb_test "q" "Quit" "quit while paging"
 
+# Check that width/height of sqrt(INT_MAX) is treated as unlimited, as
+# well as "0" and explicit "unlimited".
+foreach_with_prefix size {"0" "0x80000000" "unlimited"} {
+
+    # Alternate between "non-unlimited" values and "unlimited" values,
+    # to make sure we're not seeing stale internal state.
+
+    gdb_test "set width 200"
+    gdb_test "show width" \
+	"Number of characters gdb thinks are in a line is 200\\."
+
+    gdb_test "set height 200"
+    gdb_test "show height" \
+	"Number of lines gdb thinks are in a page is 200\\."
+
+    gdb_test "set width $size"
+    gdb_test "show width unlimited" \
+	"Number of characters gdb thinks are in a line is unlimited\\."
+
+    gdb_test "set height $size"
+    gdb_test "show height unlimited" \
+	"Number of lines gdb thinks are in a page is unlimited\\."
+}
+
 gdb_exit
 return 0
 
diff --git a/gdb/utils.c b/gdb/utils.c
index 069da23542..60af31f2e4 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -1394,10 +1394,16 @@ set_screen_size (void)
   const int sqrt_int_max = INT_MAX >> (sizeof (int) * 8 / 2);
 
   if (rows <= 0 || rows > sqrt_int_max)
-    rows = sqrt_int_max;
+    {
+      rows = sqrt_int_max;
+      lines_per_page = UINT_MAX;
+    }
 
   if (cols <= 0 || cols > sqrt_int_max)
-    cols = sqrt_int_max;
+    {
+      cols = sqrt_int_max;
+      chars_per_line = UINT_MAX;
+    }
 
   /* Update Readline's idea of the terminal size.  */
   rl_set_screen_size (rows, cols);