[ML] Remove allocators from cache after usage

docs/CHANGELOG.asciidoc

@@ -34,6 +34,13 @@
 
 * Fix "stack use after scope" memory error. (See {ml-pull}2673[#2673].)
 
+== {es} version 8.14.1
+
+=== Enhancements
+
+* Improve memory allocation management for JSON processing to reduce memory usage.
+  (See {ml-pull}2679[#2679].)
+
 == {es} version 8.14.0
 
 === Bug Fixes

include/api/CJsonOutputWriter.h

@@ -273,6 +273,9 @@ class API_EXPORT CJsonOutputWriter {
     //! \p allocatorName A unique identifier for the allocator
     void pushAllocator(const std::string& allocatorName);
 
+    //! remove allocator from cache
+    void removeAllocator(const std::string& allocatorName);
+
     //! revert to using the previous allocator for JSON output processing
     void popAllocator();
 

include/core/CBoostJsonWriterBase.h

@@ -24,10 +24,7 @@
 #include <boost/unordered_set.hpp>
 
 #include <cmath>
-#include <iomanip>
-#include <iostream>
 #include <memory>
-#include <regex>
 #include <stack>
 
 namespace json = boost::json;
@@ -134,6 +131,14 @@ class CBoostJsonWriterBase {
         return this->getAllocator()->get();
     }
 
+    void removeAllocator(const std::string& allocatorName) {
+        auto allocator = m_AllocatorCache.find(allocatorName);
+        if (allocator != m_AllocatorCache.end()) {
+            allocator->second.reset();
+            m_AllocatorCache.erase(allocator);
+        }
+    }
+
     bool isComplete() const {
         bool ret = m_Levels.empty() || m_Levels.top() == 0;
         return ret;

include/core/CScopedBoostJsonPoolAllocator.h

@@ -12,6 +12,7 @@
 #define INCLUDED_ml_core_CScopedBoostJsonPoolAllocator_h
 
 #include <boost/json.hpp>
+#include <string>
 
 namespace ml {
 namespace core {
@@ -31,14 +32,18 @@ class CScopedBoostJsonPoolAllocator {
     //! \p allocatorName Unique identifier for the allocator
     //! \p jsonOutputWriter JSON output writer that will make use of the allocator
     CScopedBoostJsonPoolAllocator(const std::string& allocatorName, T& writer)
-        : m_Writer(writer) {
+        : m_Writer(writer), m_AllocatorName(allocatorName) {
         m_Writer.pushAllocator(allocatorName);
     }
 
-    ~CScopedBoostJsonPoolAllocator() { m_Writer.popAllocator(); }
+    ~CScopedBoostJsonPoolAllocator() {
+        m_Writer.popAllocator();
+        m_Writer.removeAllocator(m_AllocatorName);
+    }
 
 private:
     T& m_Writer;
+    std::string m_AllocatorName;
 };
 }
 }

lib/api/CJsonOutputWriter.cc

@@ -850,6 +850,10 @@ void CJsonOutputWriter::pushAllocator(const std::string& allocatorName) {
     m_Writer.pushAllocator(allocatorName);
 }
 
+void CJsonOutputWriter::removeAllocator(const std::string& allocatorName) {
+    m_Writer.removeAllocator(allocatorName);
+}
+
 void CJsonOutputWriter::popAllocator() {
     m_Writer.popAllocator();
 }