[DO NOT MERGE] Cau/experiment async threadsafe fixes

src/pybind/docling_parser_v2.h

@@ -11,6 +11,7 @@
 #include <pybind/docling_resources.h>
 
 #include <v2.h>
+#include <mutex>
 
 namespace docling
 {
@@ -81,6 +82,8 @@ namespace docling
     std::map<std::string, decoder_ptr_type> key2doc;
   };
 
+
+
   docling_parser_v2::docling_parser_v2():
     docling_resources(),
     pdf_resources_dir(resource_utils::get_resources_v2_dir(true).string()),
@@ -94,6 +97,7 @@ namespace docling
     data[RESOURCE_DIR_KEY] = pdf_resources_dir;
 
     std::map<std::string, double> timings = {};
+    // Eagerly initialize font resources at parser construction to enable parallel document loading
     pdflib::pdf_resource<pdflib::PAGE_FONT>::initialise(data, timings);
   }
 
@@ -112,6 +116,7 @@ namespace docling
     data[RESOURCE_DIR_KEY] = pdf_resources_dir;
 
     std::map<std::string, double> timings = {};
+    // Eagerly initialize font resources at parser construction to enable parallel document loading
     pdflib::pdf_resource<pdflib::PAGE_FONT>::initialise(data, timings);
   }
 
@@ -334,6 +339,11 @@ namespace docling
       }
 
     auto& decoder = itr->second;
+
+    // Lock this specific document to prevent concurrent access to same document
+    // while allowing different documents to be processed in parallel
+    auto lock = decoder->get_lock();
+
     decoder->decode_document(page_boundary, do_sanitization);
 
     LOG_S(INFO) << "decoding done for key: " << key;
@@ -362,6 +372,10 @@ namespace docling
 
     auto& decoder = itr->second;
 
+    // Lock this specific document to prevent concurrent access to same document
+    // while allowing different documents to be processed in parallel
+    auto lock = decoder->get_lock();
+
     std::vector<int> pages = {page};
     decoder->decode_document(pages, page_boundary, do_sanitization);
 

src/v2/pdf_decoders/document.h

@@ -4,6 +4,7 @@
 #define PDF_DOCUMENT_DECODER_H
 
 #include <qpdf/QPDF.hh>
+#include <mutex>
 //#include <qpdf/QPDFPageObjectHelper.hh>
 
 namespace pdflib
@@ -33,6 +34,9 @@ namespace pdflib
     void decode_document(std::string page_boundary, bool do_sanitization);
 
     void decode_document(std::vector<int>& page_numbers, std::string page_boundary, bool do_sanitization);
+
+    // Thread-safe document access methods
+    std::lock_guard<std::mutex> get_lock() const { return std::lock_guard<std::mutex>(document_mutex); }
 
   private:
 
@@ -57,6 +61,10 @@ namespace pdflib
     //nlohmann::json json_toc; // table-of-contents
     nlohmann::json json_annots;
     nlohmann::json json_document;
+
+    // Per-document mutex to prevent concurrent access to same document
+    // while allowing different documents to be processed in parallel
+    mutable std::mutex document_mutex;
   };
 
   pdf_decoder<DOCUMENT>::pdf_decoder():

src/v2/pdf_resources/page_font.h

@@ -3,6 +3,10 @@
 #ifndef PDF_PAGE_FONT_RESOURCE_H
 #define PDF_PAGE_FONT_RESOURCE_H
 
+#include <mutex>
+#include <atomic>
+#include <thread>
+
 namespace pdflib
 {
 
@@ -92,6 +96,9 @@ namespace pdflib
     static font_cids      cids;
     static font_encodings encodings;
     static base_fonts     bfonts;
+
+    // Thread-safety for font cache initialization
+    static std::atomic<bool> initialized;
 
   private:
 
@@ -148,6 +155,9 @@ namespace pdflib
   font_cids      pdf_resource<PAGE_FONT>::cids = font_cids();
   font_encodings pdf_resource<PAGE_FONT>::encodings = font_encodings();
   base_fonts     pdf_resource<PAGE_FONT>::bfonts = base_fonts();
+
+  // Thread-safety initialization
+  std::atomic<bool> pdf_resource<PAGE_FONT>::initialized(false);
 
   pdf_resource<PAGE_FONT>::pdf_resource()
   {}
@@ -167,70 +177,83 @@ namespace pdflib
   void pdf_resource<PAGE_FONT>::initialise(nlohmann::json                 data,
 					   std::map<std::string, double>& timings)
   {
-    LOG_S(INFO) << __FUNCTION__ << ": " << data.dump(2);
-
-    std::string PDFS_RESOURCES_DIR = "../docling_parse/pdf_resources_v2/";
-    LOG_S(INFO) << "default pdf-resource-dir: " << PDFS_RESOURCES_DIR;
-
-    //if(data.count(RESOURCE_DIR_KEY)==0)
-    //{
-    //LOG_S(WARNING) << "resource-dir-key is missing '" << RESOURCE_DIR_KEY << "' in data: \n" << data.dump(2);
-    //}
-
-    //std::string pdf_resources_dir = data.value("pdf-resource-directory", PDFS_RESOURCES_DIR);
-    std::string pdf_resources_dir = data.value(RESOURCE_DIR_KEY, PDFS_RESOURCES_DIR);
-    pdf_resources_dir += (pdf_resources_dir.back()=='/'? "" : "/");
-
-    std::string glyphs_dir, cids_dir, encodings_dir, bfonts_dir;
-
-    if(utils::filesystem::is_dir(pdf_resources_dir))
-      {
-	LOG_S(INFO) << "pdf_resources_dir: " << pdf_resources_dir;
+    // Eager initialization - always initialize if not already done
+    // This ensures resources are available for parallel document loading
+    if (!initialized.load()) {
+      // Use a static mutex to ensure thread-safe initialization
+      static std::mutex init_mutex;
+      std::lock_guard<std::mutex> lock(init_mutex);
+
+      // Double-check pattern to avoid unnecessary initialization
+      if (!initialized.load()) {
+      LOG_S(INFO) << __FUNCTION__ << ": " << data.dump(2);
+
+      std::string PDFS_RESOURCES_DIR = "../docling_parse/pdf_resources_v2/";
+      LOG_S(INFO) << "default pdf-resource-dir: " << PDFS_RESOURCES_DIR;
+
+      //if(data.count(RESOURCE_DIR_KEY)==0)
+      //{
+      //LOG_S(WARNING) << "resource-dir-key is missing '" << RESOURCE_DIR_KEY << "' in data: \n" << data.dump(2);
+      //}
+
+      //std::string pdf_resources_dir = data.value("pdf-resource-directory", PDFS_RESOURCES_DIR);
+      std::string pdf_resources_dir = data.value(RESOURCE_DIR_KEY, PDFS_RESOURCES_DIR);
+      pdf_resources_dir += (pdf_resources_dir.back()=='/'? "" : "/");
+
+      std::string glyphs_dir, cids_dir, encodings_dir, bfonts_dir;
+
+      if(utils::filesystem::is_dir(pdf_resources_dir))
+        {
+	  LOG_S(INFO) << "pdf_resources_dir: " << pdf_resources_dir;
 
-	glyphs_dir    = pdf_resources_dir+"glyphs/";
-	cids_dir      = pdf_resources_dir+"cmap-resources/";
-	encodings_dir = pdf_resources_dir+"encodings/";
-	bfonts_dir    = pdf_resources_dir+"fonts/";	
-      }
-    else
+	  glyphs_dir    = pdf_resources_dir+"glyphs/";
+	  cids_dir      = pdf_resources_dir+"cmap-resources/";
+	  encodings_dir = pdf_resources_dir+"encodings/";
+	  bfonts_dir    = pdf_resources_dir+"fonts/";	
+        }
+      else
+        {
+	  std::string message = "no existing pdf_resources_dir: " +  pdf_resources_dir; 
+	  LOG_S(ERROR) << message;
+	  throw std::logic_error(message);
+        }
+
+      utils::timer timer;
+
       {
-	std::string message = "no existing pdf_resources_dir: " +  pdf_resources_dir; 
-	LOG_S(ERROR) << message;
-	throw std::logic_error(message);
-      }
-
-    utils::timer timer;
-
-    {
-      timer.reset();
+        timer.reset();
 
-      glyphs.initialise(glyphs_dir);
+        glyphs.initialise(glyphs_dir);
 
-      timings["init-glyphs"] = timer.get_time();
-    }
+        timings["init-glyphs"] = timer.get_time();
+      }
 
-    {
-      timer.reset();
-
-      cids.initialise(cids_dir);
-
-      timings["init-cids"] = timer.get_time();
-    }
+      {
+        timer.reset();
+        
+        cids.initialise(cids_dir);
+        
+        timings["init-cids"] = timer.get_time();
+      }
 
-    {
-      timer.reset();
+      {
+        timer.reset();
 
-      encodings.initialise(encodings_dir, glyphs);
+        encodings.initialise(encodings_dir, glyphs);
 
-      timings["init-encodings"] = timer.get_time();
-    }
+        timings["init-encodings"] = timer.get_time();
+      }
 
-    {
-      timer.reset();
+      {
+        timer.reset();
 
-      bfonts.initialise(bfonts_dir, glyphs);
+        bfonts.initialise(bfonts_dir, glyphs);
 
-      timings["init-bfonts"] = timer.get_time();
+        timings["init-bfonts"] = timer.get_time();
+      }
+
+        initialized.store(true, std::memory_order_release);
+      }
     }
   }
 

src/v2/pdf_resources/page_font/base_fonts.h

@@ -5,6 +5,8 @@
 
 #include <set>
 #include <map>
+#include <mutex>
+#include <atomic>
 
 //#include <filesystem>
 
@@ -43,15 +45,19 @@ namespace pdflib
 
   private:
 
-    bool initialized;
+    static std::atomic<bool> initialized;
+    static std::mutex init_mutex;
 
     std::set<std::string> core_14_fonts;
 
     std::map<std::string, base_font_type> name_to_basefont;
   };
 
-  base_fonts::base_fonts():
-    initialized(false)
+  // Static member definitions
+  std::atomic<bool> base_fonts::initialized(false);
+  std::mutex base_fonts::init_mutex;
+
+  base_fonts::base_fonts()
   {}
 
   base_fonts::~base_fonts()
@@ -160,7 +166,17 @@ namespace pdflib
   template<typename glyphs_type>
   void base_fonts::initialise(std::string dirname, glyphs_type& glyphs)
   {
-    if(initialized)
+    // Use double-checked locking pattern for thread-safe initialization
+    if(initialized.load(std::memory_order_acquire))
+      {
+	LOG_S(WARNING) << "skipping base_fonts::initialise, already initialized ...";
+	return;
+      }
+
+    std::lock_guard<std::mutex> lock(init_mutex);
+
+    // Check again after acquiring lock
+    if(initialized.load(std::memory_order_acquire))
       {
 	LOG_S(WARNING) << "skipping base_fonts::initialise, already initialized ...";
 	return;
@@ -226,7 +242,7 @@ namespace pdflib
 	  }
       }
 
-    initialized = true;
+    initialized.store(true, std::memory_order_release);
   }
 
   std::string base_fonts::read_fontname(std::string filename)

src/v2/pdf_resources/page_font/encodings.h

@@ -3,6 +3,9 @@
 #ifndef PDF_PAGE_FONT_ENCODINGS_H
 #define PDF_PAGE_FONT_ENCODINGS_H
 
+#include <mutex>
+#include <atomic>
+
 namespace pdflib
 {
 
@@ -21,13 +24,17 @@ namespace pdflib
 
   private:
 
-    bool initialized;
+    static std::atomic<bool> initialized;
+    static std::mutex init_mutex;
 
     std::map<font_encoding_name, font_encoding> name_to_encoding;
   };
 
-  font_encodings::font_encodings():
-    initialized(false)
+  // Static member definitions
+  std::atomic<bool> font_encodings::initialized(false);
+  std::mutex font_encodings::init_mutex;
+
+  font_encodings::font_encodings()
   {}
 
   font_encodings::~font_encodings()
@@ -41,7 +48,17 @@ namespace pdflib
   template<typename glyphs_type>
   void font_encodings::initialise(std::string dirname, glyphs_type& glyphs)
   {
-    if(initialized)
+    // Use double-checked locking pattern for thread-safe initialization
+    if(initialized.load(std::memory_order_acquire))
+      {
+	LOG_S(WARNING) << "skipping font_encodings::initialise, already initialized ...";
+	return;
+      }
+
+    std::lock_guard<std::mutex> lock(init_mutex);
+
+    // Check again after acquiring lock
+    if(initialized.load(std::memory_order_acquire))
       {
 	LOG_S(WARNING) << "skipping font_encodings::initialise, already initialized ...";
 	return;
@@ -60,7 +77,7 @@ namespace pdflib
         encoding.initialise(item.first, dirname+"/"+item.second, glyphs);
       }
 
-    initialized = true;
+    initialized.store(true, std::memory_order_release);
   }
 
 }