diff --git a/lldb/include/lldb/API/SBFile.h b/lldb/include/lldb/API/SBFile.h
--- a/lldb/include/lldb/API/SBFile.h
+++ b/lldb/include/lldb/API/SBFile.h
@@ -18,6 +18,7 @@
 
 public:
   SBFile();
+  SBFile(FileSP file_sp);
   SBFile(FILE *file, bool transfer_ownership);
   SBFile(int fd, const char *mode, bool transfer_ownership);
   ~SBFile();
@@ -33,7 +34,6 @@
 
 private:
   FileSP m_opaque_sp;
-  SBFile(FileSP file_sp);
 };
 
 } // namespace lldb
diff --git a/lldb/packages/Python/lldbsuite/test/python_api/file_handle/TestFileHandle.py b/lldb/packages/Python/lldbsuite/test/python_api/file_handle/TestFileHandle.py
--- a/lldb/packages/Python/lldbsuite/test/python_api/file_handle/TestFileHandle.py
+++ b/lldb/packages/Python/lldbsuite/test/python_api/file_handle/TestFileHandle.py
@@ -13,8 +13,53 @@
 import lldb
 from lldbsuite.test import  lldbtest
 from lldbsuite.test.decorators import (
-    add_test_categories, no_debug_info_test, skipIf)
-
+    add_test_categories, skipIf, skipIfWindows)
+
+class OhNoe(Exception):
+    pass
+
+class BadIO(io.TextIOBase):
+    @property
+    def closed(self):
+        return False
+    def writable(self):
+        return True
+    def readable(self):
+        return True
+    def write(self, s):
+        raise OhNoe('OH NOE')
+    def read(self, n):
+        raise OhNoe("OH NOE")
+    def flush(self):
+        raise OhNoe('OH NOE')
+
+# This class will raise an exception while it's being
+# converted into a C++ object by swig
+class ReallyBadIO(io.TextIOBase):
+    def fileno(self):
+        return 999
+    def writable(self):
+        raise OhNoe("OH NOE!!!")
+
+class MutableBool():
+    def __init__(self, value):
+        self.value = value
+    def set(self, value):
+        self.value = bool(value)
+    def __bool__(self):
+        return self.value
+
+class FlushTestIO(io.StringIO):
+    def __init__(self, mutable_flushed, mutable_closed):
+        super(FlushTestIO, self).__init__()
+        self.mut_flushed = mutable_flushed
+        self.mut_closed = mutable_closed
+    def close(self):
+        self.mut_closed.set(True)
+        return super(FlushTestIO, self).close()
+    def flush(self):
+        self.mut_flushed.set(True)
+        return super(FlushTestIO, self).flush()
 
 @contextmanager
 def replace_stdout(new):
@@ -36,6 +81,7 @@
 
 class FileHandleTestCase(lldbtest.TestBase):
 
+    NO_DEBUG_INFO_TESTCASE = True
     mydir = lldbtest.Base.compute_mydir(__file__)
 
     # The way this class interacts with the debugger is different
@@ -84,7 +130,8 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
+    @skipIfWindows # FIXME pre-existing bug, should be fixed
+                   # when we delete the FILE* typemaps.
     def test_legacy_file_out_script(self):
         with open(self.out_filename, 'w') as f:
             self.debugger.SetOutputFileHandle(f, False)
@@ -100,7 +147,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_legacy_file_out(self):
         with open(self.out_filename, 'w') as f:
             self.debugger.SetOutputFileHandle(f, False)
@@ -110,7 +156,8 @@
             self.assertIn('deadbeef', f.read())
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
+    @skipIfWindows # FIXME pre-existing bug, should be fixed
+                   # when we delete the FILE* typemaps.
     def test_legacy_file_err_with_get(self):
         with open(self.out_filename, 'w') as f:
             self.debugger.SetErrorFileHandle(f, False)
@@ -124,7 +171,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_legacy_file_err(self):
         with open(self.out_filename, 'w') as f:
             self.debugger.SetErrorFileHandle(f, False)
@@ -135,7 +181,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_sbfile_type_errors(self):
         sbf = lldb.SBFile()
         self.assertRaises(TypeError, sbf.Write, None)
@@ -146,8 +191,7 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
-    def test_sbfile_write(self):
+    def test_sbfile_write_fileno(self):
         with open(self.out_filename, 'w') as f:
             sbf = lldb.SBFile(f.fileno(), "w", False)
             self.assertTrue(sbf.IsValid())
@@ -161,8 +205,20 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
-    def test_sbfile_read(self):
+    def test_sbfile_write(self):
+        with open(self.out_filename, 'w') as f:
+            sbf = lldb.SBFile(f)
+            e, n = sbf.Write(b'FOO\n')
+            self.assertTrue(e.Success())
+            self.assertEqual(n, 4)
+            sbf.Close()
+            self.assertTrue(f.closed)
+        with open(self.out_filename, 'r') as f:
+            self.assertEqual(f.read().strip(), 'FOO')
+
+
+    @add_test_categories(['pyapi'])
+    def test_sbfile_read_fileno(self):
         with open(self.out_filename, 'w') as f:
             f.write('FOO')
         with open(self.out_filename, 'r') as f:
@@ -175,7 +231,21 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
+    def test_sbfile_read(self):
+        with open(self.out_filename, 'w') as f:
+            f.write('foo')
+        with open(self.out_filename, 'r') as f:
+            sbf = lldb.SBFile(f)
+            buf = bytearray(100)
+            e, n = sbf.Read(buf)
+            self.assertTrue(e.Success())
+            self.assertEqual(n, 3)
+            self.assertEqual(buf[:n], b'foo')
+            sbf.Close()
+            self.assertTrue(f.closed)
+
+
+    @add_test_categories(['pyapi'])
     def test_fileno_out(self):
         with open(self.out_filename, 'w') as f:
             sbf = lldb.SBFile(f.fileno(), "w", False)
@@ -189,7 +259,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_fileno_help(self):
         with open(self.out_filename, 'w') as f:
             sbf = lldb.SBFile(f.fileno(), "w", False)
@@ -201,7 +270,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_immediate(self):
         with open(self.out_filename, 'w') as f:
             ret = lldb.SBCommandReturnObject()
@@ -220,7 +288,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_fileno_inout(self):
         with open(self.in_filename, 'w') as f:
             f.write("help help\n")
@@ -244,7 +311,6 @@
 
 
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     def test_fileno_error(self):
         with open(self.out_filename, 'w') as f:
 
@@ -263,7 +329,6 @@
 
     #FIXME This shouldn't fail for python2 either.
     @add_test_categories(['pyapi'])
-    @no_debug_info_test
     @skipIf(py_version=['<', (3,)])
     def test_replace_stdout(self):
         f = io.StringIO()
@@ -272,3 +337,222 @@
             self.handleCmd('script sys.stdout.write("lol")',
                 collect_result=False, check=False)
             self.assertEqual(sys.stdout, f)
+
+
+    @add_test_categories(['pyapi'])
+    def test_sbfile_write_borrowed(self):
+        with open(self.out_filename, 'w') as f:
+            sbf = lldb.SBFile.Create(f, borrow=True)
+            e, n = sbf.Write(b'FOO')
+            self.assertTrue(e.Success())
+            self.assertEqual(n, 3)
+            sbf.Close()
+            self.assertFalse(f.closed)
+            f.write('BAR\n')
+        with open(self.out_filename, 'r') as f:
+            self.assertEqual(f.read().strip(), 'FOOBAR')
+
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_write_forced(self):
+        with open(self.out_filename, 'w') as f:
+            written = MutableBool(False)
+            orig_write = f.write
+            def mywrite(x):
+                written.set(True)
+                return orig_write(x)
+            f.write = mywrite
+            sbf = lldb.SBFile.Create(f, force_io_methods=True)
+            e, n = sbf.Write(b'FOO')
+            self.assertTrue(written)
+            self.assertTrue(e.Success())
+            self.assertEqual(n, 3)
+            sbf.Close()
+            self.assertTrue(f.closed)
+        with open(self.out_filename, 'r') as f:
+            self.assertEqual(f.read().strip(), 'FOO')
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_write_forced_borrowed(self):
+        with open(self.out_filename, 'w') as f:
+            written = MutableBool(False)
+            orig_write = f.write
+            def mywrite(x):
+                written.set(True)
+                return orig_write(x)
+            f.write = mywrite
+            sbf = lldb.SBFile.Create(f, borrow=True, force_io_methods=True)
+            e, n = sbf.Write(b'FOO')
+            self.assertTrue(written)
+            self.assertTrue(e.Success())
+            self.assertEqual(n, 3)
+            sbf.Close()
+            self.assertFalse(f.closed)
+        with open(self.out_filename, 'r') as f:
+            self.assertEqual(f.read().strip(), 'FOO')
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_write_string(self):
+        f = io.StringIO()
+        sbf = lldb.SBFile(f)
+        e, n = sbf.Write(b'FOO')
+        self.assertEqual(f.getvalue().strip(), "FOO")
+        self.assertTrue(e.Success())
+        self.assertEqual(n, 3)
+        sbf.Close()
+        self.assertTrue(f.closed)
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_write_bytes(self):
+        f = io.BytesIO()
+        sbf = lldb.SBFile(f)
+        e, n = sbf.Write(b'FOO')
+        self.assertEqual(f.getvalue().strip(), b"FOO")
+        self.assertTrue(e.Success())
+        self.assertEqual(n, 3)
+        sbf.Close()
+        self.assertTrue(f.closed)
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_read_string(self):
+        f = io.StringIO('zork')
+        sbf = lldb.SBFile(f)
+        buf = bytearray(100)
+        e, n = sbf.Read(buf)
+        self.assertTrue(e.Success())
+        self.assertEqual(buf[:n], b'zork')
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_read_string_one_byte(self):
+        f = io.StringIO('z')
+        sbf = lldb.SBFile(f)
+        buf = bytearray(1)
+        e, n = sbf.Read(buf)
+        self.assertTrue(e.Fail())
+        self.assertEqual(n, 0)
+        self.assertEqual(e.GetCString(), "can't read less than 6 bytes from a utf8 text stream")
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_read_bytes(self):
+        f = io.BytesIO(b'zork')
+        sbf = lldb.SBFile(f)
+        buf = bytearray(100)
+        e, n = sbf.Read(buf)
+        self.assertTrue(e.Success())
+        self.assertEqual(buf[:n], b'zork')
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_sbfile_out(self):
+        with open(self.out_filename, 'w') as f:
+            sbf = lldb.SBFile(f)
+            status = self.debugger.SetOutputFile(sbf)
+            self.assertTrue(status.Success())
+            self.handleCmd('script 2+2')
+        with open(self.out_filename, 'r') as f:
+            self.assertEqual(f.read().strip(), '4')
+
+
+    @add_test_categories(['pyapi'])
+    def test_sbfile_error(self):
+        with open(self.out_filename, 'w') as f:
+            sbf = lldb.SBFile(f)
+            status = self.debugger.SetErrorFile(sbf)
+            self.assertTrue(status.Success())
+            self.handleCmd('lolwut', check=False, collect_result=False)
+        with open(self.out_filename, 'r') as f:
+            errors = f.read()
+            self.assertTrue(re.search(r'error:.*lolwut', errors))
+
+
+    @add_test_categories(['pyapi'])
+    def test_exceptions(self):
+        self.assertRaises(TypeError, lldb.SBFile, None)
+        self.assertRaises(TypeError, lldb.SBFile, "ham sandwich")
+        if sys.version_info[0] < 3:
+            self.assertRaises(TypeError, lldb.SBFile, ReallyBadIO())
+        else:
+            self.assertRaises(OhNoe, lldb.SBFile, ReallyBadIO())
+            error, n = lldb.SBFile(BadIO()).Write(b"FOO")
+            self.assertEqual(n, 0)
+            self.assertTrue(error.Fail())
+            self.assertEqual(error.GetCString(), "OhNoe('OH NOE')")
+            error, n = lldb.SBFile(BadIO()).Read(bytearray(100))
+            self.assertEqual(n, 0)
+            self.assertTrue(error.Fail())
+            self.assertEqual(error.GetCString(), "OhNoe('OH NOE')")
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_exceptions_logged(self):
+        messages = list()
+        self.debugger.SetLoggingCallback(messages.append)
+        self.handleCmd('log enable lldb script')
+        self.debugger.SetOutputFile(lldb.SBFile(BadIO()))
+        self.handleCmd('script 1+1')
+        self.assertTrue(any('OH NOE' in msg for msg in messages))
+
+
+    @add_test_categories(['pyapi'])
+    @skipIf(py_version=['<', (3,)])
+    def test_flush(self):
+        flushed = MutableBool(False)
+        closed = MutableBool(False)
+        f = FlushTestIO(flushed, closed)
+        self.assertFalse(flushed)
+        self.assertFalse(closed)
+        sbf = lldb.SBFile(f)
+        self.assertFalse(flushed)
+        self.assertFalse(closed)
+        sbf = None
+        self.assertFalse(flushed)
+        self.assertTrue(closed)
+        self.assertTrue(f.closed)
+
+        flushed = MutableBool(False)
+        closed = MutableBool(False)
+        f = FlushTestIO(flushed, closed)
+        self.assertFalse(flushed)
+        self.assertFalse(closed)
+        sbf = lldb.SBFile.Create(f, borrow=True)
+        self.assertFalse(flushed)
+        self.assertFalse(closed)
+        sbf = None
+        self.assertTrue(flushed)
+        self.assertFalse(closed)
+        self.assertFalse(f.closed)
+
+
+    @add_test_categories(['pyapi'])
+    def test_fileno_flush(self):
+        with open(self.out_filename, 'w') as f:
+            f.write("foo")
+            sbf = lldb.SBFile(f)
+            sbf.Write(b'bar')
+            sbf = None
+            self.assertTrue(f.closed)
+        with open(self.out_filename, 'r') as f:
+            self.assertEqual(f.read(), 'foobar')
+
+        with open(self.out_filename, 'w+') as f:
+            f.write("foo")
+            sbf = lldb.SBFile.Create(f, borrow=True)
+            sbf.Write(b'bar')
+            sbf = None
+            self.assertFalse(f.closed)
+            f.seek(0)
+            self.assertEqual(f.read(), 'foobar')
diff --git a/lldb/scripts/Python/python-typemaps.swig b/lldb/scripts/Python/python-typemaps.swig
--- a/lldb/scripts/Python/python-typemaps.swig
+++ b/lldb/scripts/Python/python-typemaps.swig
@@ -372,6 +372,65 @@
   $1 = $1 || PyCallable_Check(reinterpret_cast<PyObject*>($input));
 }
 
+
+%typemap(in) lldb::FileSP {
+  using namespace lldb_private;
+  if (PythonFile::Check($input)) {
+    PythonFile py_file(PyRefType::Borrowed, $input);
+    auto sp = unwrapOrSetPythonException(py_file.ConvertToFile());
+    if (sp)
+      $1 = sp;
+    else
+      return nullptr;
+  }
+}
+
+%typemap(in) lldb::FileSP FORCE_IO_METHODS {
+  using namespace lldb_private;
+  if (PythonFile::Check($input)) {
+    PythonFile py_file(PyRefType::Borrowed, $input);
+    auto sp = unwrapOrSetPythonException(py_file.ConvertToFileForcingUseOfScriptingIOMethods());
+    if (sp)
+      $1 = sp;
+    else
+      return nullptr;
+  }
+}
+
+%typemap(in) lldb::FileSP BORROWED {
+  using namespace lldb_private;
+  if (PythonFile::Check($input)) {
+    PythonFile py_file(PyRefType::Borrowed, $input);
+    auto sp = unwrapOrSetPythonException(py_file.ConvertToFile(/*borrowed=*/true));
+    if (sp)
+      $1 = sp;
+    else
+      return nullptr;
+  }
+}
+
+%typemap(in) lldb::FileSP BORROWED_FORCE_IO_METHODS {
+  using namespace lldb_private;
+  if (PythonFile::Check($input)) {
+    PythonFile py_file(PyRefType::Borrowed, $input);
+    auto sp = unwrapOrSetPythonException(py_file.ConvertToFileForcingUseOfScriptingIOMethods(/*borrowed=*/true));
+    if (sp)
+      $1 = sp;
+    else
+      return nullptr;
+  }
+}
+
+%typecheck(SWIG_TYPECHECK_POINTER) lldb::FileSP {
+  if (lldb_private::PythonFile::Check($input)) {
+    $1 = 1;
+  } else {
+    PyErr_Clear();
+    $1 = 0;
+  }
+}
+
+
 // FIXME both of these paths wind up calling fdopen() with no provision for ever calling
 // fclose() on the result.  SB interfaces that use FILE* should be deprecated for scripting
 // use and this typemap should eventually be removed.
diff --git a/lldb/scripts/interface/SBFile.i b/lldb/scripts/interface/SBFile.i
--- a/lldb/scripts/interface/SBFile.i
+++ b/lldb/scripts/interface/SBFile.i
@@ -15,9 +15,53 @@
 class SBFile
 {
 public:
+
     SBFile();
+
+    %feature("docstring", "
+    Initialize a SBFile from a file descriptor.  mode is
+    'r', 'r+', or 'w', like fdopen.");
     SBFile(int fd, const char *mode, bool transfer_ownership);
 
+    %feature("docstring", "initialize a SBFile from a python file object");
+    SBFile(FileSP file);
+
+    %extend {
+        static lldb::SBFile MakeBorrowed(lldb::FileSP BORROWED) {
+            return lldb::SBFile(BORROWED);
+        }
+        static lldb::SBFile MakeForcingIOMethods(lldb::FileSP FORCE_IO_METHODS) {
+            return lldb::SBFile(FORCE_IO_METHODS);
+        }
+        static lldb::SBFile MakeBorrowedForcingIOMethods(lldb::FileSP BORROWED_FORCE_IO_METHODS) {
+            return lldb::SBFile(BORROWED_FORCE_IO_METHODS);
+        }
+    }
+
+    %pythoncode {
+        @classmethod
+        def Create(cls, file, borrow=False, force_io_methods=False):
+            """
+            Create a SBFile from a python file object, with options.
+
+            If borrow is set then the underlying file will
+            not be closed when the SBFile is closed or destroyed.
+
+            If force_scripting_io is set then the python read/write
+            methods will be called even if a file descriptor is available.
+            """
+            if borrow:
+                if force_io_methods:
+                    return cls.MakeBorrowedForcingIOMethods(file)
+                else:
+                    return cls.MakeBorrowed(file)
+            else:
+                if force_io_methods:
+                    return cls.MakeForcingIOMethods(file)
+                else:
+                    return cls(file)
+    }
+
     ~SBFile ();
 
     %feature("autodoc", "Read(buffer) -> SBError, bytes_read") Read;
diff --git a/lldb/source/API/SBFile.cpp b/lldb/source/API/SBFile.cpp
--- a/lldb/source/API/SBFile.cpp
+++ b/lldb/source/API/SBFile.cpp
@@ -16,7 +16,9 @@
 
 SBFile::~SBFile() {}
 
-SBFile::SBFile(FileSP file_sp) : m_opaque_sp(file_sp) {}
+SBFile::SBFile(FileSP file_sp) : m_opaque_sp(file_sp) {
+  LLDB_RECORD_DUMMY(void, SBfile, SBFile, (FileSP), file_sp);
+}
 
 SBFile::SBFile() { LLDB_RECORD_CONSTRUCTOR_NO_ARGS(SBFile); }
 
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
@@ -84,14 +84,19 @@
 
   PythonObject(const PythonObject &rhs) : m_py_obj(nullptr) { Reset(rhs); }
 
+  PythonObject(PythonObject &&rhs) {
+    m_py_obj = rhs.m_py_obj;
+    rhs.m_py_obj = nullptr;
+  }
+
   virtual ~PythonObject() { Reset(); }
 
   void Reset() {
     // Avoid calling the virtual method since it's not necessary
     // to actually validate the type of the PyObject if we're
     // just setting to null.
-    if (Py_IsInitialized())
-      Py_XDECREF(m_py_obj);
+    if (m_py_obj && Py_IsInitialized())
+      Py_DECREF(m_py_obj);
     m_py_obj = nullptr;
   }
 
@@ -123,7 +128,7 @@
     // an owned reference by incrementing it.  If it is an owned
     // reference (for example the caller allocated it with PyDict_New()
     // then we must *not* increment it.
-    if (Py_IsInitialized() && type == PyRefType::Borrowed)
+    if (m_py_obj && Py_IsInitialized() && type == PyRefType::Borrowed)
       Py_XINCREF(m_py_obj);
   }
 
@@ -467,8 +472,38 @@
   void Reset(File &file, const char *mode);
 
   lldb::FileUP GetUnderlyingFile() const;
+
+  llvm::Expected<lldb::FileSP> ConvertToFile(bool borrowed = false);
+  llvm::Expected<lldb::FileSP>
+  ConvertToFileForcingUseOfScriptingIOMethods(bool borrowed = false);
 };
 
+class PythonException : public llvm::ErrorInfo<PythonException> {
+private:
+  PyObject *m_exception_type, *m_exception, *m_traceback;
+  PyObject *m_repr_bytes;
+
+public:
+  static char ID;
+  const char *toCString() const;
+  PythonException(const char *caller);
+  void Restore();
+  ~PythonException();
+  void log(llvm::raw_ostream &OS) const override;
+  std::error_code convertToErrorCode() const override;
+};
+
+template <typename T> T unwrapOrSetPythonException(llvm::Expected<T> expected) {
+  if (expected)
+    return expected.get();
+  llvm::handleAllErrors(
+      expected.takeError(), [](PythonException &E) { E.Restore(); },
+      [](const llvm::ErrorInfoBase &E) {
+        PyErr_SetString(PyExc_Exception, E.message().c_str());
+      });
+  return T();
+}
+
 } // namespace lldb_private
 
 #endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
@@ -18,6 +18,7 @@
 #include "lldb/Host/File.h"
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Interpreter/ScriptInterpreter.h"
+#include "lldb/Utility/Log.h"
 #include "lldb/Utility/Stream.h"
 
 #include "llvm/ADT/StringSwitch.h"
@@ -33,6 +34,14 @@
   s.value(llvm::formatv("Python Obj: {0:X}", GetValue()).str());
 }
 
+template <typename T> static T Take(PyObject * obj) {
+    return T(PyRefType::Owned, obj);
+}
+
+template <typename T> static T Retain(PyObject * obj) {
+  return T(PyRefType::Borrowed, obj);
+}
+
 // PythonObject
 
 void PythonObject::Dump(Stream &strm) const {
@@ -963,20 +972,19 @@
   // first-class object type anymore.  `PyFile_FromFd` is just a thin wrapper
   // over `io.open()`, which returns some object derived from `io.IOBase`. As a
   // result, the only way to detect a file in Python 3 is to check whether it
-  // inherits from `io.IOBase`.  Since it is possible for non-files to also
-  // inherit from `io.IOBase`, we additionally verify that it has the `fileno`
-  // attribute, which should guarantee that it is backed by the file system.
+  // inherits from `io.IOBase`.
   PythonObject io_module(PyRefType::Owned, PyImport_ImportModule("io"));
   PythonDictionary io_dict(PyRefType::Borrowed,
                            PyModule_GetDict(io_module.get()));
   PythonObject io_base_class = io_dict.GetItemForKey(PythonString("IOBase"));
+  assert(!PyErr_Occurred());
 
   PythonObject object_type(PyRefType::Owned, PyObject_Type(py_obj));
 
-  if (1 != PyObject_IsSubclass(object_type.get(), io_base_class.get()))
-    return false;
-  if (!object_type.HasAttribute("fileno"))
+  if (!PyObject_IsSubclass(object_type.get(), io_base_class.get())) {
+    PyErr_Clear();
     return false;
+  }
 
   return true;
 #endif
@@ -1031,4 +1039,444 @@
   return file;
 }
 
+namespace {
+class GIL {
+public:
+  GIL() {
+    m_state = PyGILState_Ensure();
+    assert(!PyErr_Occurred());
+  }
+  ~GIL() { PyGILState_Release(m_state); }
+
+protected:
+  PyGILState_STATE m_state;
+};
+}
+
+const char *PythonException::toCString() const {
+  if (m_repr_bytes) {
+    return PyBytes_AS_STRING(m_repr_bytes);
+  } else {
+    return "unknown exception";
+  }
+}
+
+PythonException::PythonException(const char *caller) {
+  assert(PyErr_Occurred());
+  m_exception_type = m_exception = m_traceback = m_repr_bytes = NULL;
+  PyErr_Fetch(&m_exception_type, &m_exception, &m_traceback);
+  PyErr_NormalizeException(&m_exception_type, &m_exception, &m_traceback);
+  if (m_exception) {
+    PyObject *repr = PyObject_Repr(m_exception);
+    if (repr) {
+      m_repr_bytes = PyUnicode_AsEncodedString(repr, "utf-8", nullptr);
+      Py_XDECREF(repr);
+    }
+  }
+
+  Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_SCRIPT);
+  LLDB_LOGF(log, "%s failed with exception: %s", caller, toCString());
+  PyErr_Clear();
+}
+void PythonException::Restore() {
+  if (m_exception_type && m_exception) {
+    PyErr_Restore(m_exception_type, m_exception, m_traceback);
+  } else {
+    PyErr_SetString(PyExc_Exception, toCString());
+  }
+  m_exception_type = m_exception = m_traceback = NULL;
+}
+
+PythonException::~PythonException() {
+  Py_XDECREF(m_exception_type);
+  Py_XDECREF(m_exception);
+  Py_XDECREF(m_traceback);
+  Py_XDECREF(m_repr_bytes);
+}
+
+void PythonException::log(llvm::raw_ostream & OS) const { OS << toCString(); }
+
+std::error_code PythonException::convertToErrorCode() const {
+  return llvm::inconvertibleErrorCode();
+}
+
+char PythonException::ID = 0;
+
+llvm::Expected<uint32_t> GetOptionsForPyObject(PythonObject & obj) {
+  uint32_t options = 0;
+#if PY_MAJOR_VERSION >= 3
+  auto readable =
+      Take<PythonObject>(PyObject_CallMethod(obj.get(), "readable", "()"));
+  if (PyErr_Occurred())
+    return llvm::make_error<PythonException>("ConvertToFile");
+  auto writable =
+      Take<PythonObject>(PyObject_CallMethod(obj.get(), "writable", "()"));
+  if (PyErr_Occurred())
+    return llvm::make_error<PythonException>("ConvertToFile");
+  if (PyObject_IsTrue(readable.get()))
+    options |= File::eOpenOptionRead;
+  if (PyObject_IsTrue(writable.get()))
+    options |= File::eOpenOptionWrite;
+#else
+  PythonString py_mode = obj.GetAttributeValue("mode").AsType<PythonString>();
+  options = File::GetOptionsFromMode(py_mode.GetString());
+#endif
+  return options;
+}
+
+// Base class template for python files.   All it knows how to do
+// is hold a reference to the python object and close or flush it
+// when the File is closed.
+namespace{
+template <typename Base> class OwnedPythonFile : public Base {
+public:
+  template <typename... Args>
+  OwnedPythonFile(const PythonFile &file, bool borrowed, Args... args)
+      : Base(args...), m_py_obj(file.get()), m_borrowed(borrowed) {
+    assert(m_py_obj);
+    Py_INCREF(m_py_obj);
+  }
+
+  ~OwnedPythonFile() override {
+    assert(m_py_obj);
+    GIL takeGIL;
+    Close();
+    Py_DECREF(m_py_obj);
+    m_py_obj = nullptr;
+  }
+
+  bool IsValid() const override {
+    GIL takeGIL;
+    auto closed =
+        Take<PythonObject>(PyObject_GetAttrString(m_py_obj, "closed"));
+    if (!closed.IsValid() || PyErr_Occurred()) {
+      PyErr_Clear();
+      return false;
+    }
+    if (PyObject_IsTrue(closed.get()))
+      return false;
+    if (PyErr_Occurred()) {
+      PyErr_Clear();
+      return false;
+    }
+    return Base::IsValid();
+  }
+
+  Status Close() override {
+    assert(m_py_obj);
+    Status py_error, base_error;
+    GIL takeGIL;
+    if (!m_borrowed) {
+      Take<PythonObject>(PyObject_CallMethod(m_py_obj, "close", "()"));
+      if (PyErr_Occurred())
+        py_error = llvm::make_error<PythonException>("Close");
+    }
+    base_error = Base::Close();
+    if (py_error.Fail())
+      return py_error;
+    return base_error;
+  };
+
+protected:
+  PyObject *m_py_obj;
+  bool m_borrowed;
+};
+}
+
+// A SimplyPythonFile is a OwnedPythonFile that just does all I/O as
+// a NativeFile
+namespace {
+class SimplePythonFile : public OwnedPythonFile<NativeFile> {
+public:
+  SimplePythonFile(int fd, uint32_t options, const PythonFile &file,
+                   bool borrowed)
+      : OwnedPythonFile(file, borrowed, fd, options, false){};
+};
+}
+
+llvm::Expected<FileSP> PythonFile::ConvertToFile(bool borrowed) {
+  if (!IsValid())
+    return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                   "invalid PythonFile");
+
+  int fd = PyObject_AsFileDescriptor(m_py_obj);
+  if (fd < 0) {
+    PyErr_Clear();
+    return ConvertToFileForcingUseOfScriptingIOMethods(borrowed);
+  }
+  auto options = GetOptionsForPyObject(*this);
+  if (!options)
+    return options.takeError();
+
+  // LLDB and python will not share I/O buffers.  We should probably
+  // flush the python buffers now.
+  Take<PythonObject>(PyObject_CallMethod(m_py_obj, "flush", "()"));
+  if (PyErr_Occurred())
+    return llvm::make_error<PythonException>("Flush");
+
+  FileSP file_sp;
+  if (borrowed) {
+    // In this case we we don't need to retain the python
+    // object at all.
+    file_sp = std::make_shared<NativeFile>(fd, options.get(), false);
+  } else {
+    file_sp = std::static_pointer_cast<File>(
+        std::make_shared<SimplePythonFile>(fd, options.get(), *this, borrowed));
+  }
+  if (!file_sp->IsValid())
+    return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                   "invalid File");
+
+  return file_sp;
+}
+
+#if PY_MAJOR_VERSION >= 3
+
+namespace {
+class PythonBuffer {
+public:
+  // you must check PyErr_Occurred() after calling this constructor.
+  PythonBuffer(PythonObject &obj, int flags = PyBUF_SIMPLE) : m_buffer({}) {
+    PyObject_GetBuffer(obj.get(), &m_buffer, flags);
+  }
+  ~PythonBuffer() {
+    if (m_buffer.obj) {
+      PyBuffer_Release(&m_buffer);
+    }
+  }
+  Py_buffer &get() { return m_buffer; }
+
+protected:
+  Py_buffer m_buffer;
+};
+}
+
+// OwnedPythonFile<Base>::IsValid() chains into Base::IsValid()
+// File::IsValid() is false by default, but for the following classes
+// we want the file to be considered valid as long as the python bits
+// are valid.
+namespace {
+class PresumptivelyValidFile : public File {
+public:
+  bool IsValid() const override { return true; };
+};
+}
+
+// Shared methods between TextPythonFile and BinaryPythonFile
+namespace {
+class PythonIOFile : public OwnedPythonFile<PresumptivelyValidFile> {
+public:
+  PythonIOFile(const PythonFile &file, bool borrowed)
+      : OwnedPythonFile(file, borrowed){};
+
+  ~PythonIOFile() override { Close(); }
+
+  Status Close() override {
+    assert(m_py_obj);
+    GIL takeGIL;
+    if (m_borrowed)
+      return Flush();
+    Take<PythonObject>(PyObject_CallMethod(m_py_obj, "close", "()"));
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Close"));
+    return Status();
+  };
+
+  Status Flush() override {
+    GIL takeGIL;
+    Take<PythonObject>(PyObject_CallMethod(m_py_obj, "flush", "()"));
+    Status error;
+    if (PyErr_Occurred())
+      error = llvm::make_error<PythonException>("Flush");
+    return error;
+  }
+};
+}
+
+namespace {
+class BinaryPythonFile : public PythonIOFile {
+  friend class PythonFile;
+
+protected:
+  int m_descriptor;
+
+public:
+  BinaryPythonFile(int fd, const PythonFile &file, bool borrowed)
+      : PythonIOFile(file, borrowed),
+        m_descriptor(File::DescriptorIsValid(fd) ? fd
+                                                 : File::kInvalidDescriptor) {}
+
+  int GetDescriptor() const override { return m_descriptor; }
+
+  Status Write(const void *buf, size_t &num_bytes) override {
+    GIL takeGIL;
+    auto pybuffer = Take<PythonObject>(PyMemoryView_FromMemory(
+        const_cast<char *>((const char *)buf), num_bytes, PyBUF_READ));
+    num_bytes = 0;
+    auto bytes_written = Take<PythonObject>(
+        PyObject_CallMethod(m_py_obj, "write", "(O)", pybuffer.get()));
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Write"));
+    long l_bytes_written = PyLong_AsLong(bytes_written.get());
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Write"));
+    num_bytes = l_bytes_written;
+    if (l_bytes_written < 0 || (unsigned long)l_bytes_written != num_bytes) {
+      return Status("overflow");
+    }
+    return Status();
+  }
+
+  Status Read(void *buf, size_t &num_bytes) override {
+    GIL takeGIL;
+    auto pybuffer_obj = Take<PythonObject>(PyObject_CallMethod(
+        m_py_obj, "read", "(L)", (unsigned long long)num_bytes));
+    num_bytes = 0;
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Read"));
+    if (pybuffer_obj.IsNone()) {
+      // EOF
+      num_bytes = 0;
+      return Status();
+    }
+    PythonBuffer pybuffer(pybuffer_obj);
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Read"));
+    memcpy(buf, pybuffer.get().buf, pybuffer.get().len);
+    num_bytes = pybuffer.get().len;
+    return Status();
+  }
+};
+}
+
+namespace {
+class TextPythonFile : public PythonIOFile {
+  friend class PythonFile;
+
+protected:
+  int m_descriptor;
+
+public:
+  TextPythonFile(int fd, const PythonFile &file, bool borrowed)
+      : PythonIOFile(file, borrowed),
+        m_descriptor(File::DescriptorIsValid(fd) ? fd
+                                                 : File::kInvalidDescriptor) {}
+
+  int GetDescriptor() const override { return m_descriptor; }
+
+  Status Write(const void *buf, size_t &num_bytes) override {
+    GIL takeGIL;
+    auto pystring = Take<PythonObject>(
+        PyUnicode_FromStringAndSize((const char *)buf, num_bytes));
+    num_bytes = 0;
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Write"));
+    auto bytes_written = Take<PythonObject>(
+        PyObject_CallMethod(m_py_obj, "write", "(O)", pystring.get()));
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Write"));
+    long l_bytes_written = PyLong_AsLong(bytes_written.get());
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Write"));
+    num_bytes = l_bytes_written;
+    if (l_bytes_written < 0 || (unsigned long)l_bytes_written != num_bytes) {
+      return Status("overflow");
+    }
+    return Status();
+  }
+
+  Status Read(void *buf, size_t &num_bytes) override {
+    GIL takeGIL;
+    size_t num_chars = num_bytes / 6;
+    size_t orig_num_bytes = num_bytes;
+    num_bytes = 0;
+    if (orig_num_bytes < 6) {
+      return Status("can't read less than 6 bytes from a utf8 text stream");
+    }
+    auto pystring = Take<PythonObject>(PyObject_CallMethod(
+        m_py_obj, "read", "(L)", (unsigned long long)num_chars));
+    if (pystring.IsNone()) {
+      // EOF
+      return Status();
+    }
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Read"));
+    if (!PyUnicode_Check(pystring.get()))
+      return Status("read() didn't return a str");
+    if (PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Read"));
+    Py_ssize_t size;
+    const char *utf8 = PyUnicode_AsUTF8AndSize(pystring.get(), &size);
+    if (!utf8 || PyErr_Occurred())
+      return Status(llvm::make_error<PythonException>("Read"));
+    assert(size >= 0 && (size_t)size <= orig_num_bytes);
+    memcpy(buf, utf8, size);
+    num_bytes = size;
+    return Status();
+  }
+};
+}
+
+#endif
+
+llvm::Expected<FileSP> PythonFile::ConvertToFileForcingUseOfScriptingIOMethods(
+    bool borrowed) {
+
+  assert(!PyErr_Occurred());
+
+  if (!IsValid())
+    return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                   "invalid PythonFile");
+
+#if PY_MAJOR_VERSION < 3
+
+  return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                 "not supported on python 2");
+
+#else
+
+  int fd = PyObject_AsFileDescriptor(m_py_obj);
+  if (fd < 0) {
+    PyErr_Clear();
+    fd = File::kInvalidDescriptor;
+  }
+
+  auto io_module = Take<PythonObject>(PyImport_ImportModule("io"));
+  auto io_dict = Retain<PythonDictionary>(PyModule_GetDict(io_module.get()));
+  auto textIOBase = io_dict.GetItemForKey(PythonString("TextIOBase"));
+  auto rawIOBase = io_dict.GetItemForKey(PythonString("BufferedIOBase"));
+  auto bufferedIOBase = io_dict.GetItemForKey(PythonString("RawIOBase"));
+
+  // python interpreter badly janked if we can't get those.
+  assert(!PyErr_Occurred());
+
+  FileSP file_sp;
+  if (PyObject_IsInstance(m_py_obj, textIOBase.get())) {
+    file_sp = std::static_pointer_cast<File>(
+        std::make_shared<TextPythonFile>(fd, *this, borrowed));
+  }
+  if (PyErr_Occurred())
+    return llvm::make_error<PythonException>("Convert");
+
+  if (!file_sp && (PyObject_IsInstance(m_py_obj, rawIOBase.get()) ||
+             PyObject_IsInstance(m_py_obj, bufferedIOBase.get()))) {
+    file_sp = std::static_pointer_cast<File>(
+        std::make_shared<BinaryPythonFile>(fd, *this, borrowed));
+  }
+  if (PyErr_Occurred())
+    return llvm::make_error<PythonException>("Convert");
+
+  if (!file_sp)
+    return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                   "python file is neither text nor binary");
+
+  if (!file_sp->IsValid())
+    return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                   "invalid File");
+
+  return file_sp;
+
+#endif
+}
+
 #endif