[lldb/ScriptInterpreter] Extract IO redirection logic

This patch takes the IO redirection logic from ScriptInterpreterPython
and moves it into the interpreter library so that it can be used by
other script interpreters. I've turned it into a RAII object so that we
don't have to worry about cleaning up in the calling code.

Differential revision: https://reviews.llvm.org/D82396

1 files changed, 20 insertions, 95 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index 39f76e7..40ce7d9 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -42,6 +42,7 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormatAdapters.h"
 
@@ -895,15 +896,6 @@ bool ScriptInterpreterPythonImpl::GetEmbeddedInterpreterModuleObjects() {
   return m_run_one_line_function.IsValid();
 }
 
-static void ReadThreadBytesReceived(void *baton, const void *src,
-                                    size_t src_len) {
-  if (src && src_len) {
-    Stream *strm = (Stream *)baton;
-    strm->Write(src, src_len);
-    strm->Flush();
-  }
-}
-
 bool ScriptInterpreterPythonImpl::ExecuteOneLine(
     llvm::StringRef command, CommandReturnObject *result,
     const ExecuteScriptOptions &options) {
@@ -919,77 +911,23 @@ bool ScriptInterpreterPythonImpl::ExecuteOneLine(
     // another string to pass to PyRun_SimpleString messes up the escaping.  So
     // we use the following more complicated method to pass the command string
     // directly down to Python.
-    Debugger &debugger = m_debugger;
-
-    FileSP input_file_sp;
-    StreamFileSP output_file_sp;
-    StreamFileSP error_file_sp;
-    Communication output_comm(
-        "lldb.ScriptInterpreterPythonImpl.ExecuteOneLine.comm");
-    bool join_read_thread = false;
-    if (options.GetEnableIO()) {
-      if (result) {
-        input_file_sp = debugger.GetInputFileSP();
-        // Set output to a temporary file so we can forward the results on to
-        // the result object
-
-        Pipe pipe;
-        Status pipe_result = pipe.CreateNew(false);
-        if (pipe_result.Success()) {
-#if defined(_WIN32)
-          lldb::file_t read_file = pipe.GetReadNativeHandle();
-          pipe.ReleaseReadFileDescriptor();
-          std::unique_ptr<ConnectionGenericFile> conn_up(
-              new ConnectionGenericFile(read_file, true));
-#else
-          std::unique_ptr<ConnectionFileDescriptor> conn_up(
-              new ConnectionFileDescriptor(pipe.ReleaseReadFileDescriptor(),
-                                           true));
-#endif
-          if (conn_up->IsConnected()) {
-            output_comm.SetConnection(std::move(conn_up));
-            output_comm.SetReadThreadBytesReceivedCallback(
-                ReadThreadBytesReceived, &result->GetOutputStream());
-            output_comm.StartReadThread();
-            join_read_thread = true;
-            FILE *outfile_handle =
-                fdopen(pipe.ReleaseWriteFileDescriptor(), "w");
-            output_file_sp = std::make_shared<StreamFile>(outfile_handle, true);
-            error_file_sp = output_file_sp;
-            if (outfile_handle)
-              ::setbuf(outfile_handle, nullptr);
-
-            result->SetImmediateOutputFile(
-                debugger.GetOutputStream().GetFileSP());
-            result->SetImmediateErrorFile(
-                debugger.GetErrorStream().GetFileSP());
-          }
-        }
-      }
-      if (!input_file_sp || !output_file_sp || !error_file_sp)
-        debugger.AdoptTopIOHandlerFilesIfInvalid(input_file_sp, output_file_sp,
-                                                 error_file_sp);
-    } else {
-      auto nullin = FileSystem::Instance().Open(
-                                  FileSpec(FileSystem::DEV_NULL),
-                                  File::eOpenOptionRead);
-      auto nullout = FileSystem::Instance().Open(
-                                  FileSpec(FileSystem::DEV_NULL),
-                                  File::eOpenOptionWrite);
-      if (!nullin) {
-        result->AppendErrorWithFormatv("failed to open /dev/null: {0}\n",
-                                       llvm::fmt_consume(nullin.takeError()));
-        return false;
-      }
-      if (!nullout) {
-        result->AppendErrorWithFormatv("failed to open /dev/null: {0}\n",
-                                       llvm::fmt_consume(nullout.takeError()));
-        return false;
-      }
-      input_file_sp = std::move(nullin.get());
-      error_file_sp = output_file_sp = std::make_shared<StreamFile>(std::move(nullout.get()));
+    llvm::Expected<std::unique_ptr<ScriptInterpreterIORedirect>>
+        io_redirect_or_error =
+            options.GetEnableIO()
+                ? ScriptInterpreterIORedirect::Create(m_debugger, result)
+                : ScriptInterpreterIORedirect::Create();
+    if (!io_redirect_or_error) {
+      if (result)
+        result->AppendErrorWithFormatv(
+            "failed to redirect I/O: {0}\n",
+            llvm::fmt_consume(io_redirect_or_error.takeError()));
+      else
+        llvm::consumeError(io_redirect_or_error.takeError());
+      return false;
     }
 
+    ScriptInterpreterIORedirect &io_redirect = **io_redirect_or_error;
+
     bool success = false;
     {
       // WARNING!  It's imperative that this RAII scope be as tight as
@@ -1005,8 +943,9 @@ bool ScriptInterpreterPythonImpl::ExecuteOneLine(
           Locker::AcquireLock | Locker::InitSession |
               (options.GetSetLLDBGlobals() ? Locker::InitGlobals : 0) |
               ((result && result->GetInteractive()) ? 0 : Locker::NoSTDIN),
-          Locker::FreeAcquiredLock | Locker::TearDownSession, input_file_sp,
-          output_file_sp->GetFileSP(), error_file_sp->GetFileSP());
+          Locker::FreeAcquiredLock | Locker::TearDownSession,
+          io_redirect.GetInputFile(), io_redirect.GetOutputFile(),
+          io_redirect.GetErrorFile());
 
       // Find the correct script interpreter dictionary in the main module.
       PythonDictionary &session_dict = GetSessionDictionary();
@@ -1032,21 +971,7 @@ bool ScriptInterpreterPythonImpl::ExecuteOneLine(
         }
       }
 
-      // Flush our output and error file handles
-      output_file_sp->Flush();
-      error_file_sp->Flush();
-    }
-
-    if (join_read_thread) {
-      // Close the write end of the pipe since we are done with our one line
-      // script. This should cause the read thread that output_comm is using to
-      // exit
-      output_file_sp->GetFile().Close();
-      // The close above should cause this thread to exit when it gets to the
-      // end of file, so let it get all its data
-      output_comm.JoinReadThread();
-      // Now we can close the read end of the pipe
-      output_comm.Disconnect();
+      io_redirect.Flush();
     }
 
     if (success)