[lldb][progress] Add progress manager class

Per discussions from llvm#81026,
it was decided that having a class that manages a map of progress
reports would be beneficial in order to categorize them. This class is a
part of the overall `Progress` class and utilizes a map that keeps a
count of how many times a progress report category has been sent. This
would be used with the new debugger broadcast bit added in
llvm#81169 so that a user listening
with that bit will receive grouped progress reports.

Author: chelcassanova

lldb/include/lldb/Core/Progress.h

@@ -11,6 +11,7 @@
 
 #include "lldb/Utility/ConstString.h"
 #include "lldb/lldb-types.h"
+#include "llvm/ADT/StringMap.h"
 #include <atomic>
 #include <mutex>
 #include <optional>
@@ -119,6 +120,32 @@ class Progress {
   bool m_complete = false;
 };
 
+/// A class used to group progress reports by category. This is done by using a
+/// map that maintains a refcount of each category of progress reports that have
+/// come in. Keeping track of progress reports this way will be done if a
+/// debugger is listening to the eBroadcastBitProgressByCategory broadcast bit.
+class ProgressManager {
+public:
+  ProgressManager();
+  ~ProgressManager();
+
+  static void Initialize();
+  static void Terminate();
+  // Control the refcount of the progress report category as needed
+  void Increment(std::string);
+  void Decrement(std::string);
+
+  // Public accessor for the class instance
+  static ProgressManager &Instance();
+
+private:
+  // Manage the class instance internally using a std::optional
+  static std::optional<ProgressManager> &InstanceImpl();
+
+  llvm::StringMap<uint64_t> m_progress_map;
+  std::mutex m_progress_map_mutex;
+};
+
 } // namespace lldb_private
 
 #endif // LLDB_CORE_PROGRESS_H

lldb/source/Core/Progress.cpp

@@ -66,3 +66,47 @@ void Progress::ReportProgress() {
                              m_debugger_id);
   }
 }
+
+void ProgressManager::Initialize() {
+  lldbassert(!InstanceImpl() && "A progress report manager already exists.");
+  InstanceImpl().emplace();
+}
+
+void ProgressManager::Terminate() {
+  lldbassert(InstanceImpl() &&
+             "A progress report manager has already been terminated.");
+  InstanceImpl().reset();
+}
+
+std::optional<ProgressManager> &ProgressManager::InstanceImpl() {
+  static std::optional<ProgressManager> g_progress_manager;
+  return g_progress_manager;
+}
+
+ProgressManager::ProgressManager() : m_progress_map() {}
+
+ProgressManager::~ProgressManager() {}
+
+ProgressManager &ProgressManager::Instance() { return *InstanceImpl(); }
+
+void ProgressManager::Increment(std::string title) {
+  std::lock_guard<std::mutex> lock(m_progress_map_mutex);
+  auto pair = m_progress_map.insert(std::pair(title, 1));
+
+  // If pair.first is not empty after insertion it means that that
+  // category was entered for the first time and should not be incremented
+  if (!pair.first->first().empty())
+    ++pair.first->second;
+}
+
+void ProgressManager::Decrement(std::string title) {
+  std::lock_guard<std::mutex> lock(m_progress_map_mutex);
+  auto pos = m_progress_map.find(title);
+
+  if (pos == m_progress_map.end())
+    return;
+
+  // Remove the category from the map if the refcount reaches 0
+  if (--pos->second == 0)
+    m_progress_map.erase(title);
+}