PowerPC: Add RAII handling for breakpoint updates

bbf72e7 made a change where you can pass `false` to certain MemChecks
functions to get them to skip performing an "update" step. It was then
up to the caller to call the Update function later.

This commit changes the implementation so that, instead of the caller
passing in a boolean that controls whether a function calls Update, the
function now returns an object that on destruction will call Update.
Callers that are fine with Update being called right away can skip
storing the object in a variable and thereby call Update immediately,
and callers that want to call Update later can keep the object around.
This new design reduces the risk that someone will forget calling
Update.

Source/Core/Core/PowerPC/BreakPoints.cpp

@@ -256,6 +256,7 @@ MemChecks::TMemChecksStr MemChecks::GetStrings() const
 void MemChecks::AddFromStrings(const TMemChecksStr& mc_strings)
 {
   const Core::CPUThreadGuard guard(m_system);
+  DelayedMemCheckUpdate delayed_update(this);
 
   for (const std::string& mc_string : mc_strings)
   {
@@ -283,13 +284,11 @@ void MemChecks::AddFromStrings(const TMemChecksStr& mc_strings)
       mc.condition = Expression::TryParse(condition);
     }
 
-    Add(std::move(mc), false);
+    delayed_update |= Add(std::move(mc));
   }
-
-  Update();
 }
 
-void MemChecks::Add(TMemCheck memory_check, bool update)
+DelayedMemCheckUpdate MemChecks::Add(TMemCheck memory_check)
 {
   const Core::CPUThreadGuard guard(m_system);
 
@@ -310,8 +309,7 @@ void MemChecks::Add(TMemCheck memory_check, bool update)
     m_mem_checks.emplace_back(std::move(memory_check));
   }
 
-  if (update)
-    Update();
+  return DelayedMemCheckUpdate(this, true);
 }
 
 bool MemChecks::ToggleEnable(u32 address)
@@ -326,22 +324,19 @@ bool MemChecks::ToggleEnable(u32 address)
   return true;
 }
 
-bool MemChecks::Remove(u32 address, bool update)
+DelayedMemCheckUpdate MemChecks::Remove(u32 address)
 {
   const auto iter =
       std::find_if(m_mem_checks.cbegin(), m_mem_checks.cend(),
                    [address](const auto& check) { return check.start_address == address; });
 
   if (iter == m_mem_checks.cend())
-    return false;
+    return DelayedMemCheckUpdate(this, false);
 
   const Core::CPUThreadGuard guard(m_system);
   m_mem_checks.erase(iter);
 
-  if (update)
-    Update();
-
-  return true;
+  return DelayedMemCheckUpdate(this, true);
 }
 
 void MemChecks::Clear()

Source/Core/Core/PowerPC/BreakPoints.h

@@ -97,6 +97,8 @@ private:
   Core::System& m_system;
 };
 
+class DelayedMemCheckUpdate;
+
 // Memory breakpoints
 class MemChecks
 {
@@ -115,13 +117,13 @@ public:
   TMemChecksStr GetStrings() const;
   void AddFromStrings(const TMemChecksStr& mc_strings);
 
-  void Add(TMemCheck memory_check, bool update = true);
+  DelayedMemCheckUpdate Add(TMemCheck memory_check);
 
   bool ToggleEnable(u32 address);
 
   TMemCheck* GetMemCheck(u32 address, size_t size = 1);
   bool OverlapsMemcheck(u32 address, u32 length) const;
-  bool Remove(u32 address, bool update = true);
+  DelayedMemCheckUpdate Remove(u32 address);
 
   void Update();
   void Clear();
@@ -132,3 +134,39 @@ private:
   Core::System& m_system;
   bool m_mem_breakpoints_set = false;
 };
+
+class DelayedMemCheckUpdate final
+{
+public:
+  DelayedMemCheckUpdate(MemChecks* memchecks, bool update_needed = false)
+      : m_memchecks(memchecks), m_update_needed(update_needed)
+  {
+  }
+
+  DelayedMemCheckUpdate(const DelayedMemCheckUpdate&) = delete;
+  DelayedMemCheckUpdate(DelayedMemCheckUpdate&& other) = delete;
+  DelayedMemCheckUpdate& operator=(const DelayedMemCheckUpdate&) = delete;
+  DelayedMemCheckUpdate& operator=(DelayedMemCheckUpdate&& other) = delete;
+
+  ~DelayedMemCheckUpdate()
+  {
+    if (m_update_needed)
+      m_memchecks->Update();
+  }
+
+  DelayedMemCheckUpdate& operator|=(DelayedMemCheckUpdate&& other)
+  {
+    if (m_memchecks == other.m_memchecks)
+    {
+      m_update_needed |= other.m_update_needed;
+      other.m_update_needed = false;
+    }
+    return *this;
+  }
+
+  operator bool() const { return m_update_needed; }
+
+private:
+  MemChecks* m_memchecks;
+  bool m_update_needed;
+};

Source/Core/Core/PowerPC/GDBStub.cpp

@@ -172,12 +172,12 @@ static void RemoveBreakpoint(BreakpointType type, u32 addr, u32 len)
   else
   {
     auto& memchecks = Core::System::GetInstance().GetPowerPC().GetMemChecks();
+    DelayedMemCheckUpdate delayed_update(&memchecks);
     while (memchecks.GetMemCheck(addr, len) != nullptr)
     {
-      memchecks.Remove(addr, false);
+      delayed_update |= memchecks.Remove(addr);
       INFO_LOG_FMT(GDB_STUB, "gdb: removed a memcheck: {:08x} bytes at {:08x}", len, addr);
     }
-    memchecks.Update();
   }
   Host_PPCBreakpointsChanged();
 }

Source/Core/DolphinQt/Debugger/MemoryViewWidget.cpp

@@ -996,6 +996,7 @@ void MemoryViewWidget::ToggleBreakpoint(u32 addr, bool row)
 
   {
     const Core::CPUThreadGuard guard(m_system);
+    DelayedMemCheckUpdate delayed_update(&memchecks);
 
     for (int i = 0; i < breaks; i++)
     {
@@ -1014,16 +1015,14 @@ void MemoryViewWidget::ToggleBreakpoint(u32 addr, bool row)
         check.log_on_hit = m_do_log;
         check.break_on_hit = true;
 
-        memchecks.Add(std::move(check), false);
+        delayed_update |= memchecks.Add(std::move(check));
       }
       else if (check_ptr != nullptr)
       {
         // Using the pointer fixes misaligned breakpoints (0x11 breakpoint in 0x10 aligned view).
-        memchecks.Remove(check_ptr->start_address, false);
+        delayed_update |= memchecks.Remove(check_ptr->start_address);
       }
     }
-
-    memchecks.Update();
   }
 
   emit Host::GetInstance()->PPCBreakpointsChanged();