[lldb] Print an error for unsupported combinations of log options

[JDevlieghere]

Summary

Print an error for unsupported combinations of log handlers and log options. Only the stream log handler takes a file and only the circular and stream handler take a buffer size. This cannot be dealt with through option groups because the option combinations depend on the requested handler.

[bulbazord]

lldb/source/Commands/CommandObjectLog.cpp

180–184

lldb/test/Shell/Log/TestHandlers.test

6

[JDevlieghere]

Update error message

[bulbazord]

LGTM

[clayborg]

lldb/test/Shell/Log/TestHandlers.test

2–3

Can we use the long option names for readability here?

[JDevlieghere]

lldb/test/Shell/Log/TestHandlers.test

2–3

Absolutely

lldb/source/Commands/CommandObjectLog.cpp

bool DoExecute(Args &args, CommandReturnObject &result) override {
 
     if (m_options.handler == eLogHandlerCircular &&
         m_options.buffer_size.GetCurrentValue() == 0) {
       result.AppendError(
           "the circular buffer handler requires a non-zero buffer size.\n");
       return false;
     }
 
+    if ((m_options.handler != eLogHandlerCircular &&
+         m_options.handler != eLogHandlerStream) &&
+        m_options.buffer_size.GetCurrentValue() != 0) {
+      result.AppendError("a buffer size can only be specified for the circular "
+                         "and stream buffer handler.\n");
+      return false;
+    }
+
+    if (m_options.handler != eLogHandlerStream && m_options.log_file) {
+      result.AppendError(
+          "a file name can only be specified for the stream handler.\n");
+      return false;
+    }
+
     // Store into a std::string since we're about to shift the channel off.
     const std::string channel = std::string(args[0].ref());
     args.Shift(); // Shift off the channel
     char log_file[PATH_MAX];
     if (m_options.log_file)
       m_options.log_file.GetPath(log_file, sizeof(log_file));
     else
       log_file[0] = '\0';

lldb/test/Shell/Log/TestHandlers.test

+# RUN: %lldb -o 'log enable --log-handler os --file /tmp/foo  gdb-remote packets' 2>&1 | FileCheck %s  --check-prefix UNSUPPORTED-FILE
+# RUN: %lldb -o 'log enable --log-handler os --buffer 10  gdb-remote packets' 2>&1 | FileCheck %s  --check-prefix UNSUPPORTED-BUFFER
+
+# UNSUPPORTED-FILE: a file name can only be specified for the stream handler
+# UNSUPPORTED-BUFFER:  a buffer size can only be specified for the circular and stream buffer handler