Fix !N and !-N commands and add a test case.

<rdar://problem/31713267>

llvm-svn: 300785

lldb/packages/Python/lldbsuite/test/functionalities/history/TestHistoryRecall.py

@@ -0,0 +1,45 @@
+"""
+Make sure the !N and !-N commands work properly.
+"""
+
+from __future__ import print_function
+
+
+import os
+import time
+import re
+import lldb
+import lldbsuite.test.lldbutil as lldbutil
+from lldbsuite.test.lldbtest import *
+
+
+class TestHistoryRecall(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    # If your test case doesn't stress debug info, the 
+    # set this to true.  That way it won't be run once for
+    # each debug info format.
+    NO_DEBUG_INFO_TESTCASE = True
+
+    def test_history_recall(self):
+        """Test the !N and !-N functionality of the command interpreter."""
+        self.sample_test()
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+
+    def sample_test(self):
+        interp = self.dbg.GetCommandInterpreter()
+        result = lldb.SBCommandReturnObject()
+        interp.HandleCommand("command history", result, True)
+        interp.HandleCommand("platform list", result, True)
+        
+        interp.HandleCommand("!0", result, False)
+        self.assertTrue(result.Succeeded(), "!0 command did not work: %s"%(result.GetError()))
+        self.assertTrue("command history" in result.GetOutput(), "!0 didn't rerun command history")
+
+        interp.HandleCommand("!-1", result, False)
+        self.assertTrue(result.Succeeded(), "!-1 command did not work: %s"%(result.GetError()))
+        self.assertTrue("host:" in result.GetOutput(), "!-1 didn't rerun platform list.")

lldb/source/Commands/CommandObjectCommands.cpp

@@ -50,7 +50,11 @@ class CommandObjectCommandsHistory : public CommandObjectParsed {
 public:
   CommandObjectCommandsHistory(CommandInterpreter &interpreter)
       : CommandObjectParsed(interpreter, "command history",
-                            "Dump the history of commands in this session.",
+                            "Dump the history of commands in this session.\n"
+                            "Commands in the history list can be run again "
+                            "using \"!<INDEX>\".   \"!-<OFFSET>\" will re-run "
+                            "the command that is <OFFSET> commands from the end"
+                            " of the list (counting the current command).",
                             nullptr),
         m_options() {}
 

lldb/source/Interpreter/CommandHistory.cpp

@@ -47,13 +47,13 @@ CommandHistory::FindString(llvm::StringRef input_str) const {
 
   size_t idx = 0;
   if (input_str.front() == '-') {
-    if (input_str.drop_front(2).getAsInteger(0, idx))
+    if (input_str.drop_front(1).getAsInteger(0, idx))
       return llvm::None;
     if (idx >= m_history.size())
       return llvm::None;
     idx = m_history.size() - idx;
   } else {
-    if (input_str.drop_front().getAsInteger(0, idx))
+    if (input_str.getAsInteger(0, idx))
       return llvm::None;
     if (idx >= m_history.size())
       return llvm::None;