Make some code not manipulate the underlying buffer of a StreamString

[zturner]

Summary

I have locally a a very large patch which removes the method of StreamString that returns a reference to the underlying std::string buffer, and instead returns a StringRef. There were 1 or 2 instances where someone was relying on this function to reach into the underlying buffer and do stuff like insert or erase from it. This seems like a huge hack, and in the future as I move code towards llvm::raw_ostream this will be incompatible with LLVM's api anyway since it does not allow such things. The only non-trivial fix to this was in something Cocoa related. I don't really understand this code, and I can't test it, but the patch here is intended to be NFC and just re-writing the logic in terms of something that doesn't modify the internal Stream buffer.

If someone could test it for me I would appreciate.

[tfiala]

I will give this a run a bit later this morning. Should be no later than early afternoon.

[tfiala]

LGTM. Built and passed all existing tests.

lldb/trunk/source/Plugins/Language/ObjC/Cocoa.cpp

bool lldb_private::formatters::NSURLSummaryProvider(
 
   uint32_t ptr_size = process_sp->GetAddressByteSize();
 
   lldb::addr_t valobj_addr = valobj.GetValueAsUnsigned(0);
 
   if (!valobj_addr)
     return false;
 
-  const char *class_name = descriptor->GetClassName().GetCString();
+  llvm::StringRef class_name = descriptor->GetClassName().GetStringRef();
 
-  if (!class_name || !*class_name)
+  if (!class_name.equals("NSURL"))
     return false;
 
-  if (strcmp(class_name, "NSURL") == 0) {
-    uint64_t offset_text = ptr_size + ptr_size +
-                           8; // ISA + pointer + 8 bytes of data (even on 32bit)
-    uint64_t offset_base = offset_text + ptr_size;
-    CompilerType type(valobj.GetCompilerType());
-    ValueObjectSP text(
-        valobj.GetSyntheticChildAtOffset(offset_text, type, true));
-    ValueObjectSP base(
-        valobj.GetSyntheticChildAtOffset(offset_base, type, true));
-    if (!text)
-      return false;
-    if (text->GetValueAsUnsigned(0) == 0)
-      return false;
-    StreamString summary;
-    if (!NSStringSummaryProvider(*text, summary, options))
-      return false;
-    if (base && base->GetValueAsUnsigned(0)) {
-      if (summary.GetSize() > 0)
-        summary.GetString().resize(summary.GetSize() - 1);
-      summary.Printf(" -- ");
-      StreamString base_summary;
-      if (NSURLSummaryProvider(*base, base_summary, options) &&
-          base_summary.GetSize() > 0)
-        summary.Printf("%s", base_summary.GetSize() > 2
-                                 ? base_summary.GetData() + 2
-                                 : base_summary.GetData());
+  ValueObjectSP text(valobj.GetSyntheticChildAtOffset(offset_text, type, true));
+  ValueObjectSP base(valobj.GetSyntheticChildAtOffset(offset_base, type, true));
+    std::string summary_str = summary.GetString();
+
+    if (!summary_str.empty())
+      summary_str.pop_back();
+    summary_str += " -- ";
+        !base_summary.Empty()) {
+      llvm::StringRef base_str = base_summary.GetString();
+      if (base_str.size() > 2)
+        base_str = base_str.drop_front(2);
+      summary_str += base_str;
     }
-    if (summary.GetSize()) {
-      stream.Printf("%s", summary.GetData());
-      return true;
-    }
+    summary.Clear();
+    summary.PutCString(summary_str);
+  if (!summary.Empty()) {
+    stream.PutCString(summary.GetString());
+    return true;
   }
 
   return false;
 }
 
 bool lldb_private::formatters::NSDateSummaryProvider(
     ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
   ProcessSP process_sp = valobj.GetProcessSP();