[v4,2/2] MI: Add new command -complete

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f2b0c16ec5..87fa43dd06 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@ 
+2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>
+
+	* mi/mi-cmds.h (mi_cmd_complete): New function.
+	* mi/mi-main.c (mi_cmd_complete): Likewise.
+	* mi/mi-cmds.c: Define new MI command -complete.
+	* NEWS: Mention new -complete command.
+
 2019-01-24  Jan Vrany  <jan.vrany@fit.cvut.cz>
 
 	* completer.h (complete): New function.
diff --git a/gdb/NEWS b/gdb/NEWS
index 5309a8f923..7aa31ccb17 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -27,6 +27,13 @@ 
      'array_indexes', 'symbols', 'unions', 'deref_refs', 'actual_objects',
      'static_members', 'max_elements', 'repeat_threshold', and 'format'.
 
+* New MI commands
+
+-complete
+  This lists all the possible completions for the rest of the line, if it
+  were to be given as a command itself.  This is intended for use by MI 
+  frontends in cases when separate CLI and MI channels cannot be used.
+
 *** Changes in GDB 8.3
 
 * GDB and GDBserver now support access to additional registers on
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 64073278fa..6f7a48787e 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@ 
+2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>
+
+	* gdb.texinfo (Miscellaneous GDB/MI Commands): Document new
+	MI command -complete.
+
 2019-04-17  Alan Hayward  <alan.hayward@arm.com>
 
 	* gdb.texinfo (Other Command-Line Arguments for gdbserver)
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a3a5f3e28c..52b203fd90 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -34438,6 +34438,67 @@  fullname="/home/nickrob/myprog.c",line="73",arch="i386:x86_64"@}
 (gdb)
 @end smallexample
 
+@subheading The @code{-complete} Command
+@findex -complete
+
+@subheading Synopsis
+
+@smallexample
+-complete @var{command}
+@end smallexample
+
+Show a list of completions for partially typed CLI @var{command}.
+
+This command is intended for @sc{gdb/mi} frontends that cannot use two separate
+CLI and MI channels - for example: because of lack of PTYs like on Windows or
+because @value{GDBN} is used remotely via a SSH connection.
+
+@subheading Result
+
+The result consists of two one or two fields:
+
+@table @samp
+@item completion
+This field contains the completed @var{command}.  If @var{command}
+has no known completions, this field is omitted.
+
+@item matches
+This field contains a (possibly empty) array of matches.  It is always present.
+
+@item max_completions_reached
+This field contains @code{1} if number of known completions is above
+@code{max-completions} limit (see @ref{Completion}), otherwise it contains
+@code{0}.  It is always present.
+
+@end table
+
+@subheading @value{GDBN} Command
+
+The corresponding @value{GDBN} command is @samp{complete}.
+
+@subheading Example
+
+@smallexample
+(gdb)
+-complete br
+^done,completion="break",matches=["break","break-range"],max_completions_reached="0"
+(gdb)
+-complete "b ma"
+^done,completion="b ma",matches=["b madvise","b main"],max_completions_reached="0"
+(gdb)
+-complete "b push_b"
+^done,completion="b push_back(",
+      matches=["b A::push_back(void*)",
+               "b std::string::push_back(char)",
+               "b std::vector<int, std::allocator<int> >::push_back(int&&)"],
+      max_completions_reached="0"
+(gdb)
+-complete "nonexist"
+^done,matches=[],max_completions_reached="0"
+(gdb)
+
+@end smallexample
+
 @node Annotations
 @chapter @value{GDBN} Annotations
 
diff --git a/gdb/mi/mi-cmds.c b/gdb/mi/mi-cmds.c
index fe30ac2e82..bbc0e2bd93 100644
--- a/gdb/mi/mi-cmds.c
+++ b/gdb/mi/mi-cmds.c
@@ -75,6 +75,7 @@  static struct mi_cmd mi_cmds[] =
                    &mi_suppress_notification.breakpoint),
   DEF_MI_CMD_MI_1 ("catch-unload", mi_cmd_catch_unload,
                    &mi_suppress_notification.breakpoint),
+  DEF_MI_CMD_MI ("complete", mi_cmd_complete),
   DEF_MI_CMD_MI ("data-disassemble", mi_cmd_disassemble),
   DEF_MI_CMD_MI ("data-evaluate-expression", mi_cmd_data_evaluate_expression),
   DEF_MI_CMD_MI ("data-list-changed-registers",
diff --git a/gdb/mi/mi-cmds.h b/gdb/mi/mi-cmds.h
index 7b22ce7813..58aa2d6f77 100644
--- a/gdb/mi/mi-cmds.h
+++ b/gdb/mi/mi-cmds.h
@@ -125,6 +125,7 @@  extern mi_cmd_argv_ftype mi_cmd_var_update;
 extern mi_cmd_argv_ftype mi_cmd_enable_pretty_printing;
 extern mi_cmd_argv_ftype mi_cmd_enable_frame_filters;
 extern mi_cmd_argv_ftype mi_cmd_var_set_update_range;
+extern mi_cmd_argv_ftype mi_cmd_complete;
 
 /* Description of a single command.  */
 
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 17ca807471..0d8a27e6cc 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -2726,6 +2726,51 @@  mi_multi_location_breakpoint_output_fixed (ui_out *uiout)
   return mi_uiout->version () >= 3 || fix_multi_location_breakpoint_output;
 }
 
+/* Implement the "-complete" command.  */
+
+void
+mi_cmd_complete (const char *command, char **argv, int argc)
+{
+  if (argc != 1)
+    error (_("Usage: -complete COMMAND"));
+
+  if (max_completions == 0)
+    error (_("max-completions is zero, completion is disabled.\n"));
+
+  int quote_char = '\0';
+  const char *word;
+
+  completion_result result = complete (argv[0], &word, &quote_char);
+
+  std::string arg_prefix (argv[0], word - argv[0]);
+
+  struct ui_out *uiout = current_uiout;
+
+  if (result.number_matches > 0)
+    uiout->field_fmt ("completion", "%s%s",
+                      arg_prefix.c_str (),result.match_list[0]);
+
+  {
+    ui_out_emit_list completions_emitter (uiout, "matches");
+
+    if (result.number_matches == 1)
+      uiout->field_fmt (NULL, "%s%s",
+                        arg_prefix.c_str (), result.match_list[0]);
+    else
+      {
+        result.sort_match_list ();
+        for (size_t i = 0; i < result.number_matches; i++)
+          {
+            uiout->field_fmt (NULL, "%s%s",
+                              arg_prefix.c_str (), result.match_list[i + 1]);
+          }
+      }
+  }
+  uiout->field_string ("max_completions_reached",
+                       result.number_matches == max_completions ? "1" : "0");
+}
+
+
 void
 _initialize_mi_main (void)
 {
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index d46422635b..eed638c5b2 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@ 
+2019-01-28  Jan Vrany  <jan.vrany@fit.cvut.cz>
+
+	* gdb.mi/mi-complete.exp: New file.
+	* gdb.mi/mi-complete.cc: Likewise.
+
 2019-04-15  Leszek Swirski  <leszeks@google.com>
 
 	* gdb.arch/amd64-eval.cc: New file.
diff --git a/gdb/testsuite/gdb.mi/mi-complete.cc b/gdb/testsuite/gdb.mi/mi-complete.cc
new file mode 100644
index 0000000000..3742152864
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-complete.cc
@@ -0,0 +1,40 @@ 
+/* Copyright 2018-2019 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <vector>
+
+class A
+{
+public:
+  void push_back (void *value);
+};
+
+void
+A::push_back (void *value)
+{
+  /* nothing */
+}
+
+int
+main (int argc, char **argv)
+{
+  std::vector < int >v;
+  v.push_back (1);
+  A a;
+  a.push_back (&v);
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.mi/mi-complete.exp b/gdb/testsuite/gdb.mi/mi-complete.exp
new file mode 100644
index 0000000000..692b004fd9
--- /dev/null
+++ b/gdb/testsuite/gdb.mi/mi-complete.exp
@@ -0,0 +1,72 @@ 
+# Copyright 2018-2019 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Verify GDB/MI -complete in various scenarios. This test only tests
+# -complete command, not the correctness of completions.
+
+load_lib mi-support.exp
+set MIFLAGS "-i=mi"
+
+gdb_exit
+if [mi_gdb_start] {
+    continue
+}
+
+standard_testfile .cc
+
+if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } {
+     untested "failed to compile"
+     return -1
+}
+
+mi_run_to_main
+
+mi_gdb_test "1-complete br" \
+            "1\\^done,completion=\"break\",matches=\\\[.*\"break\",.*\"break-range\".*\\\],max_completions_reached=\"0\"" \
+            "-complete br"
+
+# Check empty completion list.
+mi_gdb_test "5-complete bogus" \
+            "5\\^done,matches=\\\[\\\],max_completions_reached=\"0\"" \
+            "-complete bogus"
+
+# Check completions for commands with space.
+mi_gdb_test "4-complete \"b mai\"" \
+            "4\\^done,completion=\"b main\",matches=\\\[.*\"b main\".*\\\],max_completions_reached=\"0\"" \
+            "-complete \"b mai\""
+
+# Check wildmatching.
+mi_gdb_test "5-complete \"b push_ba\"" \
+            "5\\^done,completion=\"b push_back\\(\",matches=\\\[.*\"b A::push_back\\(void\\*\\)\".*\\\],max_completions_reached=\"0\"" \
+            "-complete \"b push_ba\", wildmatching"
+
+mi_gdb_test "-info-gdb-mi-command complete" \
+            "\\^done,command=\{exists=\"true\"\}" \
+            "-info-gdb-mi-command complete"
+
+# Limit max completions and check that max_completions_reached=\"0\" is set
+# to 1.
+send_gdb "set max-completions 1\n"
+
+mi_gdb_test "2-complete br" \
+            ".*2\\^done,completion=\"br\[A-Za-z0-9-\]+\",matches=\\\[\"br\[A-Za-z0-9-\]+\"\\\],max_completions_reached=\"1\"" \
+            "-complete br, max-completions 1"
+
+# Disable completions and check an error is returned
+send_gdb "set max-completions 0\n"
+
+mi_gdb_test "3-complete br" \
+            ".*3\\^error,msg=\".*" \
+            "-complete br, max-completions 0"