Handle trailing spaces on "settings set" command more correctly

Summary:
Currently we have some settings which treat "\ " on settings set commands specially. E.g., it is
a valid way of specifying an argument of " " to a target. However, this fails if "\ " is the last
argument as CommandObjectSettingsSet strips trailing whitespace. This resulted in a surprising
argument of "\" to the target.

This patch disables the training whitespace removal at a global
level. Instead, for each argument type we locally determine whether whitespace stripping makes
sense. Currently, I strip whitespace for all simple object type except of regex and
format-string, with the rationale that these two object types do their own complex parsing and we
want to interfere with them as least as possible. Specifically, stripping the whitespace of a
regex "\ " will result in a (surprising?) error "trailing backslash". Furthermore, the default
value of dissasembly-format setting already contains a trailing space and there is no way for the
user to type this in manually if we strip whitespace.

Reviewers: clayborg, zturner

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D7592

llvm-svn: 229382

1 files changed, 7 insertions, 6 deletions

diff --git a/lldb/source/Interpreter/OptionValueString.cpp b/lldb/source/Interpreter/OptionValueString.cpp
index a1b80d8..9012ab1 100644
--- a/lldb/source/Interpreter/OptionValueString.cpp
+++ b/lldb/source/Interpreter/OptionValueString.cpp
@@ -57,24 +57,25 @@ OptionValueString::SetValueFromCString (const char *value_cstr,
     Error error;
 
     std::string value_str_no_quotes;
-    if (value_cstr)
+    llvm::StringRef trimmed = value_cstr ? llvm::StringRef(value_cstr).trim() : llvm::StringRef();
+    if (trimmed.size() > 0)
     {
-        switch (value_cstr[0])
+        switch (trimmed.front())
         {
         case '"':
         case '\'':
             {
-                size_t len = strlen(value_cstr);
-                if (len <= 1 || value_cstr[len-1] != value_cstr[0])
+                if (trimmed.size() <= 1 || trimmed.back() != trimmed.front())
                 {
                     error.SetErrorString("mismatched quotes");
                     return error;
                 }
-                value_str_no_quotes.assign (value_cstr + 1, len - 2);
-                value_cstr = value_str_no_quotes.c_str();
+                trimmed = trimmed.drop_front().drop_back().str();
             }
             break;
         }
+        value_str_no_quotes = trimmed.str();
+        value_cstr = value_str_no_quotes.c_str();
     }
 
     switch (op)