Allow finer control over installed handler types (#193). r=ted.mielczarek

http://groups.google.com/group/google-breakpad-dev/browse_thread/thread/992a1bb09dc58a32


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@193 4c0a9323-5329-0410-9bdc-e9ce6186880e

2 files changed, 50 insertions, 27 deletions

diff --git a/src/client/windows/handler/exception_handler.cc b/src/client/windows/handler/exception_handler.cc
index d2c6e7d0..2d7bc57c 100644
--- a/src/client/windows/handler/exception_handler.cc
+++ b/src/client/windows/handler/exception_handler.cc
@@ -50,7 +50,7 @@ ExceptionHandler::ExceptionHandler(const wstring &dump_path,
                                    FilterCallback filter,
                                    MinidumpCallback callback,
                                    void *callback_context,
-                                   bool install_handler)
+                                   HandlerType handler_types)
     : filter_(filter),
       callback_(callback),
       callback_context_(callback_context),
@@ -62,7 +62,7 @@ ExceptionHandler::ExceptionHandler(const wstring &dump_path,
       next_minidump_path_c_(NULL),
       dbghelp_module_(NULL),
       minidump_write_dump_(NULL),
-      installed_handler_(install_handler),
+      handler_types_(handler_types),
       previous_filter_(NULL),
       previous_pch_(NULL),
       handler_thread_(0),
@@ -82,11 +82,10 @@ ExceptionHandler::ExceptionHandler(const wstring &dump_path,
   set_dump_path(dump_path);
 
   // Set synchronization primitives and the handler thread.  Each
-  // ExceptionHandler object gets its own handler thread, even if
-  // install_handler is false, because that's the only way to reliably
-  // guarantee sufficient stack space in an exception, and the only way to
-  // get a snapshot of the requesting thread's context outside of an
-  // exception.
+  // ExceptionHandler object gets its own handler thread because that's the
+  // only way to reliably guarantee sufficient stack space in an exception,
+  // and it allows an easy way to get a snapshot of the requesting thread's
+  // context outside of an exception.
   InitializeCriticalSection(&handler_critical_section_);
   handler_start_semaphore_ = CreateSemaphore(NULL, 0, 1, NULL);
   handler_finish_semaphore_ = CreateSemaphore(NULL, 0, 1, NULL);
@@ -105,7 +104,7 @@ ExceptionHandler::ExceptionHandler(const wstring &dump_path,
         GetProcAddress(dbghelp_module_, "MiniDumpWriteDump"));
   }
 
-  if (install_handler) {
+  if (handler_types != HANDLER_NONE) {
     if (!handler_stack_critical_section_initialized_) {
       InitializeCriticalSection(&handler_stack_critical_section_);
       handler_stack_critical_section_initialized_ = true;
@@ -119,13 +118,17 @@ ExceptionHandler::ExceptionHandler(const wstring &dump_path,
       handler_stack_ = new vector<ExceptionHandler *>();
     }
     handler_stack_->push_back(this);
-    previous_filter_ = SetUnhandledExceptionFilter(HandleException);
+
+    if (handler_types & HANDLER_EXCEPTION)
+      previous_filter_ = SetUnhandledExceptionFilter(HandleException);
 
 #if _MSC_VER >= 1400  // MSVC 2005/8
-    previous_iph_ = _set_invalid_parameter_handler(HandleInvalidParameter);
+    if (handler_types & HANDLER_INVALID_PARAMETER)
+      previous_iph_ = _set_invalid_parameter_handler(HandleInvalidParameter);
 #endif  // _MSC_VER >= 1400
 
-    previous_pch_ = _set_purecall_handler(HandlePureVirtualCall);
+    if (handler_types & HANDLER_PURECALL)
+      previous_pch_ = _set_purecall_handler(HandlePureVirtualCall);
 
     LeaveCriticalSection(&handler_stack_critical_section_);
   }
@@ -136,16 +139,19 @@ ExceptionHandler::~ExceptionHandler() {
     FreeLibrary(dbghelp_module_);
   }
 
-  if (installed_handler_) {
+  if (handler_types_ != HANDLER_NONE) {
     EnterCriticalSection(&handler_stack_critical_section_);
 
-    SetUnhandledExceptionFilter(previous_filter_);
+    if (handler_types_ & HANDLER_EXCEPTION)
+      SetUnhandledExceptionFilter(previous_filter_);
 
 #if _MSC_VER >= 1400  // MSVC 2005/8
-    _set_invalid_parameter_handler(previous_iph_);
+    if (handler_types_ & HANDLER_INVALID_PARAMETER)
+      _set_invalid_parameter_handler(previous_iph_);
 #endif  // _MSC_VER >= 1400
 
-    _set_purecall_handler(previous_pch_);
+    if (handler_types_ & HANDLER_PURECALL)
+      _set_purecall_handler(previous_pch_);
 
     if (handler_stack_->back() == this) {
       handler_stack_->pop_back();
@@ -423,7 +429,8 @@ bool ExceptionHandler::WriteMinidumpForException(EXCEPTION_POINTERS *exinfo) {
 bool ExceptionHandler::WriteMinidump(const wstring &dump_path,
                                      MinidumpCallback callback,
                                      void *callback_context) {
-  ExceptionHandler handler(dump_path, NULL, callback, callback_context, false);
+  ExceptionHandler handler(dump_path, NULL, callback, callback_context,
+                           HANDLER_NONE);
   return handler.WriteMinidump();
 }
 
diff --git a/src/client/windows/handler/exception_handler.h b/src/client/windows/handler/exception_handler.h
index a9eccd6b..c2d55609 100644
--- a/src/client/windows/handler/exception_handler.h
+++ b/src/client/windows/handler/exception_handler.h
@@ -119,17 +119,33 @@ class ExceptionHandler {
                                    MDRawAssertionInfo *assertion,
                                    bool succeeded);
 
+  // HandlerType specifies which types of handlers should be installed, if
+  // any.  Use HANDLER_NONE for an ExceptionHandler that remains idle,
+  // without catching any failures on its own.  This type of handler may
+  // still be triggered by calling WriteMinidump.  Otherwise, use a
+  // combination of the other HANDLER_ values, or HANDLER_ALL to install
+  // all handlers.
+  enum HandlerType {
+    HANDLER_NONE = 0,
+    HANDLER_EXCEPTION = 1 << 0,          // SetUnhandledExceptionFilter
+    HANDLER_INVALID_PARAMETER = 1 << 1,  // _set_invalid_parameter_handler
+    HANDLER_PURECALL = 1 << 2,           // _set_purecall_handler
+    HANDLER_ALL = HANDLER_EXCEPTION |
+                  HANDLER_INVALID_PARAMETER |
+                  HANDLER_PURECALL
+  };
+
   // Creates a new ExceptionHandler instance to handle writing minidumps.
   // Before writing a minidump, the optional filter callback will be called.
-  // Its return value determines whether or not Breakpad should write a minidump.
-  // Minidump files will be written to dump_path, and the optional callback
-  // is called after writing the dump file, as described above.
-  // If install_handler is true, then a minidump will be written whenever
-  // an unhandled exception occurs.  If it is false, minidumps will only
-  // be written when WriteMinidump is called.
+  // Its return value determines whether or not Breakpad should write a
+  // minidump.  Minidump files will be written to dump_path, and the optional
+  // callback is called after writing the dump file, as described above.
+  // handler_types specifies the types of handlers that should be installed.
   ExceptionHandler(const wstring &dump_path,
-                   FilterCallback filter, MinidumpCallback callback,
-                   void *callback_context, bool install_handler);
+                   FilterCallback filter,
+                   MinidumpCallback callback,
+                   void *callback_context,
+                   HandlerType handler_types);
   ~ExceptionHandler();
 
   // Get and set the minidump path.
@@ -244,9 +260,9 @@ class ExceptionHandler {
   HMODULE dbghelp_module_;
   MiniDumpWriteDump_type minidump_write_dump_;
 
-  // True if the ExceptionHandler installed an unhandled exception filter
-  // when created (with an install_handler parameter set to true).
-  bool installed_handler_;
+  // Tracks the handler types that were installed according to the
+  // handler_types constructor argument.
+  HandlerType handler_types_;
 
   // When installed_handler_ is true, previous_filter_ is the unhandled
   // exception filter that was set prior to installing ExceptionHandler as