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.

10 files changed, 89 insertions, 23 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f77cb67..85c62db 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+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.
+
 2018-06-04  Tom Tromey  <tom@tromey.com>
 
 	* ada-lang.h (ada_lookup_symbol_list): Update.
diff --git a/gdb/NEWS b/gdb/NEWS
index b4afd89..8fb6a2a 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -9,6 +9,9 @@
   or by inferring from the last executable used, rather than the startup
   default.
 
+* The pager now allows a "c" response, meaning to disable the pager
+  for the rest of the current command.
+
 * The commands 'info variables/functions/types' now show the source line
   numbers of symbol definitions when available.
 
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 1689e89..6191e84 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,9 @@
+2018-06-05  Tom Tromey	<tom@tromey.com>
+
+	PR cli/12326:
+	* gdb.texinfo (Screen Size): Document "c" response to pagination
+	prompt.
+
 2018-05-31  Maciej W. Rozycki  <macro@mips.com>
 
 	* gdb.texinfo (Choosing Target Byte Order): Document endianness
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 2920022..4968b37 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -23886,11 +23886,13 @@ Print ten commands just after the commands last printed.
 Certain commands to @value{GDBN} may produce large amounts of
 information output to the screen.  To help you read all of it,
 @value{GDBN} pauses and asks you for input at the end of each page of
-output.  Type @key{RET} when you want to continue the output, or @kbd{q}
-to discard the remaining output.  Also, the screen width setting
-determines when to wrap lines of output.  Depending on what is being
-printed, @value{GDBN} tries to break the line at a readable place,
-rather than simply letting it overflow onto the following line.
+output.  Type @key{RET} when you want to see one more page of output,
+@kbd{q} to discard the remaining output, or @kbd{c} to continue
+without paging for the rest of the current command.  Also, the screen
+width setting determines when to wrap lines of output.  Depending on
+what is being printed, @value{GDBN} tries to break the line at a
+readable place, rather than simply letting it overflow onto the
+following line.
 
 Normally @value{GDBN} knows the size of the screen from the terminal
 driver software.  For example, on Unix @value{GDBN} uses the termcap data base
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/ 
diff --git a/gdb/utils.c b/gdb/utils.c
index fe9a674..09381d9 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -1283,6 +1283,10 @@ show_chars_per_line (struct ui_file *file, int from_tty,
 /* Current count of lines printed on this page, chars on this line.  */
 static unsigned int lines_printed, chars_printed;
 
+/* True if pagination is disabled for just one command.  */
+
+static bool pagination_disabled_for_command;
+
 /* Buffer and start column of buffered text, for doing smarter word-
    wrapping.  When someone calls wrap_here(), we start buffering output
    that comes through fputs_filtered().  If we see a newline, we just
@@ -1467,12 +1471,14 @@ prompt_for_continue (void)
      prompt_for_continue_wait_time.  */
   using namespace std::chrono;
   steady_clock::time_point prompt_started = steady_clock::now ();
+  bool disable_pagination = pagination_disabled_for_command;
 
   if (annotation_level > 1)
     printf_unfiltered (("\n\032\032pre-prompt-for-continue\n"));
 
   strcpy (cont_prompt,
-	  "---Type <return> to continue, or q <return> to quit---");
+	  "--Type <RET> for more, q to quit, "
+	  "c to continue without paging--");
   if (annotation_level > 1)
     strcat (cont_prompt, "\n\032\032prompt-for-continue\n");
 
@@ -1502,11 +1508,14 @@ prompt_for_continue (void)
       if (p[0] == 'q')
 	/* Do not call quit here; there is no possibility of SIGINT.  */
 	throw_quit ("Quit");
+      if (p[0] == 'c')
+	disable_pagination = true;
     }
 
   /* Now we have to do this again, so that GDB will know that it doesn't
      need to save the ---Type <return>--- line at the top of the screen.  */
   reinitialize_more_filter ();
+  pagination_disabled_for_command = disable_pagination;
 
   dont_repeat ();		/* Forget prev cmd -- CR won't repeat it.  */
 }
@@ -1536,6 +1545,7 @@ reinitialize_more_filter (void)
 {
   lines_printed = 0;
   chars_printed = 0;
+  pagination_disabled_for_command = false;
 }
 
 /* Indicate that if the next sequence of characters overflows the line,
@@ -1680,6 +1690,7 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,
   /* Don't do any filtering if it is disabled.  */
   if (stream != gdb_stdout
       || !pagination_enabled
+      || pagination_disabled_for_command
       || batch_flag
       || (lines_per_page == UINT_MAX && chars_per_line == UINT_MAX)
       || top_level_interpreter () == NULL
@@ -1696,8 +1707,11 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,
   lineptr = linebuffer;
   while (*lineptr)
     {
-      /* Possible new page.  */
-      if (filter && (lines_printed >= lines_per_page - 1))
+      /* Possible new page.  Note that PAGINATION_DISABLED_FOR_COMMAND
+	 might be set during this loop, so we must continue to check
+	 it here.  */
+      if (filter && (lines_printed >= lines_per_page - 1)
+	  && !pagination_disabled_for_command)
 	prompt_for_continue ();
 
       while (*lineptr && *lineptr != '\n')
@@ -1737,8 +1751,11 @@ fputs_maybe_filtered (const char *linebuffer, struct ui_file *stream,
 	      if (wrap_column)
 		fputc_unfiltered ('\n', stream);
 
-	      /* Possible new page.  */
-	      if (lines_printed >= lines_per_page - 1)
+	      /* Possible new page.  Note that
+		 PAGINATION_DISABLED_FOR_COMMAND might be set during
+		 this loop, so we must continue to check it here.  */
+	      if (lines_printed >= lines_per_page - 1
+		  && !pagination_disabled_for_command)
 		prompt_for_continue ();
 
 	      /* Now output indentation and wrapped string.  */