Create new class, InputReaderStack, to better handle

mutexes around input readers and prevent deadlocking; modify
Debugger to use the new class.

llvm-svn: 132475

1 files changed, 14 insertions, 21 deletions

diff --git a/lldb/source/Core/Debugger.cpp b/lldb/source/Core/Debugger.cpp
index 80035363650..ace2c9a54f9 100644
--- a/lldb/source/Core/Debugger.cpp
+++ b/lldb/source/Core/Debugger.cpp
@@ -230,8 +230,7 @@ Debugger::Debugger () :
     m_listener ("lldb.Debugger"),
     m_source_manager (),
     m_command_interpreter_ap (new CommandInterpreter (*this, eScriptLanguageDefault, false)),
-    m_input_readers_mutex (Mutex::eMutexTypeRecursive),
-    m_input_readers (),
+    m_input_reader_stack (),
     m_input_reader_data ()
 {
     m_command_interpreter_ap->Initialize ();
@@ -357,14 +356,13 @@ Debugger::GetCurrentInputReader ()
 {
     InputReaderSP reader_sp;
     
-    Mutex::Locker locker (m_input_readers_mutex);
-    if (!m_input_readers.empty())
+    if (!m_input_reader_stack.IsEmpty())
     {
         // Clear any finished readers from the stack
         while (CheckIfTopInputReaderIsDone()) ;
         
-        if (!m_input_readers.empty())
-            reader_sp = m_input_readers.top();
+        if (!m_input_reader_stack.IsEmpty())
+            reader_sp = m_input_reader_stack.Top();
     }
     
     return reader_sp;
@@ -424,9 +422,8 @@ Debugger::CleanUpInputReaders ()
 {
     m_input_reader_data.clear();
     
-    Mutex::Locker locker (m_input_readers_mutex);
     // The bottom input reader should be the main debugger input reader.  We do not want to close that one here.
-    while (m_input_readers.size() > 1)
+    while (m_input_reader_stack.GetSize() > 1)
     {
         InputReaderSP reader_sp (GetCurrentInputReader ());
         if (reader_sp)
@@ -479,8 +476,7 @@ Debugger::WriteToDefaultReader (const char *bytes, size_t bytes_len)
     if (m_input_reader_data.empty())
         return;
 
-    Mutex::Locker locker (m_input_readers_mutex);
-    while (!m_input_readers.empty() && !m_input_reader_data.empty())
+    while (!m_input_reader_stack.IsEmpty() && !m_input_reader_data.empty())
     {
         // Get the input reader from the top of the stack
         InputReaderSP reader_sp (GetCurrentInputReader ());
@@ -519,8 +515,7 @@ Debugger::PushInputReader (const InputReaderSP& reader_sp)
     if (top_reader_sp)
         top_reader_sp->Notify (eInputReaderDeactivate);
 
-    Mutex::Locker locker (m_input_readers_mutex);
-    m_input_readers.push (reader_sp);
+    m_input_reader_stack.Push (reader_sp);
     reader_sp->Notify (eInputReaderActivate);
     ActivateInputReader (reader_sp);
 }
@@ -532,22 +527,21 @@ Debugger::PopInputReader (const lldb::InputReaderSP& pop_reader_sp)
 
     // The reader on the stop of the stack is done, so let the next
     // read on the stack referesh its prompt and if there is one...
-    Mutex::Locker locker (m_input_readers_mutex);
-    if (!m_input_readers.empty())
+    if (!m_input_reader_stack.IsEmpty())
     {
         // Cannot call GetCurrentInputReader here, as that would cause an infinite loop.
-        InputReaderSP reader_sp(m_input_readers.top());
+        InputReaderSP reader_sp(m_input_reader_stack.Top());
         
         if (!pop_reader_sp || pop_reader_sp.get() == reader_sp.get())
         {
-            m_input_readers.pop ();
+            m_input_reader_stack.Pop ();
             reader_sp->Notify (eInputReaderDeactivate);
             reader_sp->Notify (eInputReaderDone);
             result = true;
 
-            if (!m_input_readers.empty())
+            if (!m_input_reader_stack.IsEmpty())
             {
-                reader_sp = m_input_readers.top();
+                reader_sp = m_input_reader_stack.Top();
                 if (reader_sp)
                 {
                     ActivateInputReader (reader_sp);
@@ -563,11 +557,10 @@ bool
 Debugger::CheckIfTopInputReaderIsDone ()
 {
     bool result = false;
-    Mutex::Locker locker (m_input_readers_mutex);
-    if (!m_input_readers.empty())
+    if (!m_input_reader_stack.IsEmpty())
     {
         // Cannot call GetCurrentInputReader here, as that would cause an infinite loop.
-        InputReaderSP reader_sp(m_input_readers.top());
+        InputReaderSP reader_sp(m_input_reader_stack.Top());
         
         if (reader_sp && reader_sp->IsDone())
         {