1 files changed, 96 insertions, 0 deletions
diff --git a/sal/osl/w32/backtrace.cxx b/sal/osl/w32/backtrace.cxx
new file mode 100644
index 000000000..fab3c5043
--- /dev/null
+++ b/sal/osl/w32/backtrace.cxx
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <sal/config.h>
+
+#include <limits>
+#include <memory>
+
+#if !defined WIN32_LEAN_AND_MEAN
+# define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#include <process.h>
+#include <iostream>
+#define OPTIONAL
+#include <DbgHelp.h>
+
+#include <rtl/ustrbuf.hxx>
+#include <sal/backtrace.hxx>
+
+#include <backtraceasstring.hxx>
+
+namespace {
+
+template<typename T> T clampToULONG(T n) {
+    auto const maxUlong = std::numeric_limits<ULONG>::max();
+    return n > maxUlong ? static_cast<T>(maxUlong) : n;
+}
+
+}
+
+OUString osl::detail::backtraceAsString(sal_uInt32 maxDepth)
+{
+    std::unique_ptr<sal::BacktraceState> backtrace = sal::backtrace_get( maxDepth );
+    return sal::backtrace_to_string( backtrace.get());
+}
+
+std::unique_ptr<sal::BacktraceState> sal::backtrace_get(sal_uInt32 maxDepth)
+{
+    assert(maxDepth != 0);
+    maxDepth = clampToULONG(maxDepth);
+
+    auto pStack = new void *[maxDepth];
+    // https://msdn.microsoft.com/en-us/library/windows/desktop/bb204633.aspx
+    // "CaptureStackBackTrace function" claims that you "can capture up to
+    // MAXUSHORT frames", and on Windows Server 2003 and Windows XP it even
+    // "must be less than 63", but assume that a too large input value is
+    // clamped internally, instead of resulting in an error:
+    int nFrames = CaptureStackBackTrace( 0, static_cast<ULONG>(maxDepth), pStack, nullptr );
+
+    return std::unique_ptr<BacktraceState>(new BacktraceState{ pStack, nFrames });
+}
+
+OUString sal::backtrace_to_string(BacktraceState* backtraceState)
+{
+    HANDLE hProcess = GetCurrentProcess();
+    // https://docs.microsoft.com/en-us/windows/win32/api/dbghelp/nf-dbghelp-syminitialize
+    // says to not initialize more than once. This still leaks for some
+    // reason if called often enough.
+    static bool needsInit = true;
+    if( needsInit )
+        SymInitialize( hProcess, nullptr, true );
+    else
+        SymRefreshModuleList( hProcess );
+    SYMBOL_INFO  * pSymbol;
+    pSymbol = static_cast<SYMBOL_INFO *>(calloc( sizeof( SYMBOL_INFO ) + 1024 * sizeof( char ), 1 ));
+    assert(pSymbol);
+    pSymbol->MaxNameLen = 1024 - 1;
+    pSymbol->SizeOfStruct = sizeof( SYMBOL_INFO );
+
+    auto nFrames = backtraceState->nDepth;
+    OUStringBuffer aBuf;
+    for( int i = 0; i < nFrames; i++ )
+    {
+        SymFromAddr( hProcess, reinterpret_cast<DWORD64>(backtraceState->buffer[ i ]), nullptr, pSymbol );
+        aBuf.append( static_cast<sal_Int32>(nFrames - i - 1) );
+        aBuf.append( ": " );
+        aBuf.appendAscii( pSymbol->Name );
+        aBuf.append( " - 0x" );
+        aBuf.append( static_cast<sal_Int64>(pSymbol->Address), 16 );
+        aBuf.append( "\n" );
+    }
+
+    free( pSymbol );
+
+    return aBuf.makeStringAndClear();
+}
+
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */