Introduce a `PythonExceptionState` class.

This is a helper class which supports a number of
features including exception to string formatting with
backtrace handling and auto-restore of exception state
upon scope exit.

Additionally, unit tests are included to verify the
feature set of the class.

llvm-svn: 252994

1 files changed, 121 insertions, 0 deletions

diff --git a/lldb/unittests/ScriptInterpreter/Python/PythonExceptionStateTests.cpp b/lldb/unittests/ScriptInterpreter/Python/PythonExceptionStateTests.cpp
new file mode 100644
index 00000000000..3d7941e83a0
--- /dev/null
+++ b/lldb/unittests/ScriptInterpreter/Python/PythonExceptionStateTests.cpp
@@ -0,0 +1,121 @@
+//===-- PythonExceptionStateTest.cpp ------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "gtest/gtest.h"
+
+#include "Plugins/ScriptInterpreter/Python/lldb-python.h"
+#include "Plugins/ScriptInterpreter/Python/PythonDataObjects.h"
+#include "Plugins/ScriptInterpreter/Python/PythonExceptionState.h"
+#include "Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h"
+
+#include "PythonTestSuite.h"
+
+using namespace lldb_private;
+
+class PythonExceptionStateTest : public PythonTestSuite
+{
+  public:
+  protected:
+    void
+    RaiseException()
+    {
+        PyErr_SetString(PyExc_RuntimeError, "PythonExceptionStateTest test error");
+    }
+};
+
+TEST_F(PythonExceptionStateTest, TestExceptionStateChecking)
+{
+    PyErr_Clear();
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+
+    RaiseException();
+    EXPECT_TRUE(PythonExceptionState::HasErrorOccurred());
+
+    PyErr_Clear();
+}
+
+TEST_F(PythonExceptionStateTest, TestAcquisitionSemantics)
+{
+    PyErr_Clear();
+    PythonExceptionState no_error(false);
+    EXPECT_FALSE(no_error.IsError());
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+
+    PyErr_Clear();
+    RaiseException();
+    PythonExceptionState error(false);
+    EXPECT_TRUE(error.IsError());
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+    error.Discard();
+
+    PyErr_Clear();
+    RaiseException();
+    error.Acquire(false);
+    EXPECT_TRUE(error.IsError());
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+
+    PyErr_Clear();
+}
+
+TEST_F(PythonExceptionStateTest, TestDiscardSemantics)
+{
+    PyErr_Clear();
+
+    // Test that discarding an exception does not restore the exception
+    // state even when auto-restore==true is set
+    RaiseException();
+    PythonExceptionState error(true);
+    EXPECT_TRUE(error.IsError());
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+
+    error.Discard();
+    EXPECT_FALSE(error.IsError());
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+}
+
+TEST_F(PythonExceptionStateTest, TestManualRestoreSemantics)
+{
+    PyErr_Clear();
+    RaiseException();
+    PythonExceptionState error(false);
+    EXPECT_TRUE(error.IsError());
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+
+    error.Restore();
+    EXPECT_FALSE(error.IsError());
+    EXPECT_TRUE(PythonExceptionState::HasErrorOccurred());
+
+    PyErr_Clear();
+}
+
+TEST_F(PythonExceptionStateTest, TestAutoRestoreSemantics)
+{
+    PyErr_Clear();
+    // Test that using the auto-restore flag correctly restores the exception
+    // state on destruction, and not using the auto-restore flag correctly
+    // does NOT restore the state on destruction.
+    {
+        RaiseException();
+        PythonExceptionState error(false);
+        EXPECT_TRUE(error.IsError());
+        EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+    }
+    EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+
+    PyErr_Clear();
+    {
+        RaiseException();
+        PythonExceptionState error(true);
+        EXPECT_TRUE(error.IsError());
+        EXPECT_FALSE(PythonExceptionState::HasErrorOccurred());
+    }
+    EXPECT_TRUE(PythonExceptionState::HasErrorOccurred());
+
+    PyErr_Clear();
+}