Add "continue" response to pager

This adds a "continue" response to the pager.  If the user types "c"
in response to the pager prompt, pagination will be disabled for the
duration of one command -- but re-enabled afterward.  This is handy if
you type a command that produces a lot of output, and you don't want
to baby-sit it by typing "return" each time the prompt comes up.

Tested by the buildbot.

gdb/ChangeLog
2018-06-05  Tom Tromey	<tom@tromey.com>

	PR cli/12326:
	* NEWS: Add entry about pager.
	* utils.c (pagination_disabled_for_command): New global.
	(prompt_for_continue): Allow "c" response to prompt.
	(reinitialize_more_filter): Clear
	pagination_disabled_for_command.
	(fputs_maybe_filtered): Check pagination_disabled_for_command.

gdb/doc/ChangeLog
2018-06-05  Tom Tromey	<tom@tromey.com>

	PR cli/12326:
	* gdb.texinfo (Screen Size): Document "c" response to pagination
	prompt.

gdb/testsuite/ChangeLog
2018-06-05  Tom Tromey	<tom@tromey.com>

	PR cli/12326:
	* gdb.cp/static-print-quit.exp: Update.
	* lib/gdb.exp (pagination_prompt): Update.
	* gdb.base/page.exp: Use pagination_prompt.  Add new tests.
	* gdb.python/python.exp: Update.

5 files changed, 41 insertions, 13 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 0e98d7e..951c8db 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2018-06-05  Tom Tromey	<tom@tromey.com>
+
+	PR cli/12326:
+	* gdb.cp/static-print-quit.exp: Update.
+	* lib/gdb.exp (pagination_prompt): Update.
+	* gdb.base/page.exp: Use pagination_prompt.  Add new tests.
+	* gdb.python/python.exp: Update.
+
 2018-06-04  Joel Brobecker  <brobecker@adacore.com>
 
 	* gdb.mi/list-thread-groups-no-inferior.exp: New testcase.
diff --git a/gdb/testsuite/gdb.base/page.exp b/gdb/testsuite/gdb.base/page.exp
index 47db79f..f7557d3 100644
--- a/gdb/testsuite/gdb.base/page.exp
+++ b/gdb/testsuite/gdb.base/page.exp
@@ -47,7 +47,7 @@ gdb_test "show pagination" "State of pagination is on.*" "pagination is on"
 gdb_test_no_output "set height 10"
 send_gdb "help\n"
 gdb_expect_list "paged help" \
-	".*---Type <return> to continue, or q <return> to quit---" {
+	".*$pagination_prompt" {
     "List of classes of commands:"
     ""
     "aliases -- Aliases of other commands"
@@ -60,6 +60,25 @@ gdb_expect_list "paged help" \
 }
 gdb_test "q"
 
+gdb_test_no_output "set height 5"
+send_gdb "printf \"1\\n2\\n3\\n4\\n5\\n6\\n7\\n8\\n9\\n10\\n11\"\n"
+gdb_expect_list "paged count" \
+    ".*$pagination_prompt" {
+	1
+	2
+	3
+	4
+}
+send_gdb "c\n"
+gdb_expect_list "paged count remainder" "${gdb_prompt} " {
+    5
+    6
+    7
+    8
+    9
+    10
+    11
+}
 
 gdb_exit
 return 0
diff --git a/gdb/testsuite/gdb.cp/static-print-quit.exp b/gdb/testsuite/gdb.cp/static-print-quit.exp
index ab60a0c..22b0cf6 100644
--- a/gdb/testsuite/gdb.cp/static-print-quit.exp
+++ b/gdb/testsuite/gdb.cp/static-print-quit.exp
@@ -29,10 +29,10 @@ gdb_test_no_output "set height 2"
 
 set test "print c - <return>"
 gdb_test_multiple "print c" $test {
-    -re "\\$\[0-9\]+ = \{loooooooooooooooooooooooooooooooooooooooooooooong = 0, static field = \{\r\n---Type <return>" {
+    -re "\\$\[0-9\]+ = \{loooooooooooooooooooooooooooooooooooooooooooooong = 0, static field = \{\r\n--Type <RET>" {
 	pass $test
     }
-    -re "\r\n---Type <return>" {
+    -re "\r\n--Type <RET>" {
 	# gdb-7.1 did not crash with this testcase but it had the same bug.
 	untested "bug does not reproduce"
 	return 0
@@ -41,14 +41,14 @@ gdb_test_multiple "print c" $test {
 
 set test "print c - q <return>"
 gdb_test_multiple "" $test {
-    -re " to continue, or q <return>" {
+    -re " for more, q to quit, " {
 	pass $test
     }
 }
 
-set test "print c - to quit"
+set test "print c - remainder"
 gdb_test_multiple "" $test {
-    -re " to quit---$" {
+    -re "c to continue without paging--$" {
 	pass $test
     }
 }
diff --git a/gdb/testsuite/gdb.python/python.exp b/gdb/testsuite/gdb.python/python.exp
index 2780b78..1d7ea5b 100644
--- a/gdb/testsuite/gdb.python/python.exp
+++ b/gdb/testsuite/gdb.python/python.exp
@@ -143,13 +143,13 @@ gdb_test_no_output "set height $lines"
 
 set test "verify pagination beforehand"
 gdb_test_multiple "python print (\"\\n\" * $lines)" $test {
-    -re "---Type <return>" {
+    -re "--Type <RET>" {
 	exp_continue
     }
-    -re " to continue, or q <return>" {
+    -re " for more, q to quit" {
 	exp_continue
     }
-    -re " to quit---$" {
+    -re ", c to continue without paging--$" {
 	pass $test
     }
 }
@@ -159,13 +159,13 @@ gdb_test "python if gdb.execute('python print (\"\\\\n\" * $lines)', to_string=T
 
 set test "verify pagination afterwards"
 gdb_test_multiple "python print (\"\\n\" * $lines)" $test {
-    -re "---Type <return>" {
+    -re "--Type <RET>" {
 	exp_continue
     }
-    -re " to continue, or q <return>" {
+    -re " for more, q to quit" {
 	exp_continue
     }
-    -re " to quit---$" {
+    -re ", c to continue without paging--$" {
 	pass $test
     }
 }
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index ee66a38..aef580b 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -82,7 +82,8 @@ if ![info exists gdb_prompt] then {
 }
 
 # A regexp that matches the pagination prompt.
-set pagination_prompt [string_to_regexp "---Type <return> to continue, or q <return> to quit---"]
+set pagination_prompt \
+    "--Type <RET> for more, q to quit, c to continue without paging--"
 
 # The variable fullname_syntax_POSIX is a regexp which matches a POSIX 
 # absolute path ie. /foo/