Move option parsing out of the Args class

Summary:
The args class is used in plenty of places (a lot of them in the lower lldb
layers) for representing a list of arguments, and most of these places don't
care about option parsing. Moving the option parsing out of the class removes
the largest external dependency (there are a couple more, but these are in
static functions), and brings us closer to being able to move it to the
Utility module).

The new home for these functions is the Options class, which was already used
as an argument to the parse calls, so this just inverts the dependency between
the two.

The functions are themselves are mainly just copied -- the biggest functional
change I've made to them is to avoid modifying the input Args argument (getopt
likes to permute the argument vector), as it was weird to have another class
reorder the entries in Args class. So now the functions don't modify the input
arguments, and (for those where it makes sense) return a new Args vector
instead. I've also made the addition of a "fake arg0" (required for getopt
compatibility) an implementation detail rather than a part of interface.

While doing that I noticed that ParseForCompletion function was recording the
option indexes in the shuffled vector, but then the consumer was looking up the
entries in the unshuffled one. This manifested itself as us not being able to
complete "watchpoint set variable foo --" (because getopt would move "foo" to
the end). Surprisingly all other completions (e.g. "watchpoint set variable foo
--w") were not affected by this. However, I couldn't find a comprehensive test
for command argument completion, so I consolidated the existing tests and added
a bunch of new ones.

Reviewers: davide, jingham, zturner

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D43837

llvm-svn: 327110

1 files changed, 8 insertions, 25 deletions

diff --git a/lldb/source/Interpreter/CommandObject.cpp b/lldb/source/Interpreter/CommandObject.cpp
index 98a6a94..f4fb5ea 100644
--- a/lldb/source/Interpreter/CommandObject.cpp
+++ b/lldb/source/Interpreter/CommandObject.cpp
@@ -104,20 +104,16 @@ bool CommandObject::ParseOptions(Args &args, CommandReturnObject &result) {
     auto exe_ctx = GetCommandInterpreter().GetExecutionContext();
     options->NotifyOptionParsingStarting(&exe_ctx);
 
-    // ParseOptions calls getopt_long_only, which always skips the zero'th item
-    // in the array and starts at position 1,
-    // so we need to push a dummy value into position zero.
-    args.Unshift(llvm::StringRef("dummy_string"));
     const bool require_validation = true;
-    error = args.ParseOptions(*options, &exe_ctx,
-                              GetCommandInterpreter().GetPlatform(true),
-                              require_validation);
+    llvm::Expected<Args> args_or = options->Parse(
+        args, &exe_ctx, GetCommandInterpreter().GetPlatform(true),
+        require_validation);
 
-    // The "dummy_string" will have already been removed by ParseOptions,
-    // so no need to remove it.
-
-    if (error.Success())
+    if (args_or) {
+      args = std::move(*args_or);
       error = options->NotifyOptionParsingFinished(&exe_ctx);
+    } else
+      error = args_or.takeError();
 
     if (error.Success()) {
       if (options->VerifyOptions(result))
@@ -285,20 +281,7 @@ int CommandObject::HandleCompletion(Args &input, int &cursor_index,
     OptionElementVector opt_element_vector;
 
     if (cur_options != nullptr) {
-      // Re-insert the dummy command name string which will have been
-      // stripped off:
-      input.Unshift(llvm::StringRef("dummy-string"));
-      cursor_index++;
-
-      // I stick an element on the end of the input, because if the last element
-      // is option that requires an argument, getopt_long_only will freak out.
-
-      input.AppendArgument(llvm::StringRef("<FAKE-VALUE>"));
-
-      input.ParseArgsForCompletion(*cur_options, opt_element_vector,
-                                   cursor_index);
-
-      input.DeleteArgumentAtIndex(input.GetArgumentCount() - 1);
+      opt_element_vector = cur_options->ParseForCompletion(input, cursor_index);
 
       bool handled_by_options;
       handled_by_options = cur_options->HandleOptionCompletion(