Add some locks for concurrency

README.md

@@ -7,9 +7,6 @@ PDF::API6 - A Raku PDF API
 - [NAME](#name)
 - [DESCRIPTION](#description)
 - [EXAMPLE](#example)
-- [DIFFERENCES BETWEEN PDF::API2 AND PDF::API6](#differences-between-pdfapi2-and-pdfapi6)
-   - [PDF::API6](#pdfapi6)
-   - [TODO](#todo)
 - [SYNOPSIS](#synopsis)
 - [SECTION I: Input/Output Methods (inherited from PDF)](#section-i-inputoutput-methods-inherited-from-pdf)
    - [Input/Output](#inputoutput)
@@ -141,30 +138,6 @@ $pdf.save-as: "tmp/hello-world.pdf";
 
 ![example.pdf](https://raw.githubusercontent.com/pdf-raku/PDF-API6/master/tmp/.previews/hello-world-001.png)
 
-# DIFFERENCES BETWEEN PDF::API2 AND PDF::API6
-
-## PDF::API6
-
-- Has a Graphics State engine. This is based on the graphics operators and variables as described PDF 32000 chapter 8 "Graphics and the operators".
-
-- Supports the creation and manipulation of XObject Forms and Patterns.
-
-- Implements an Object Graph model for data access. A PDF file is modelled as an object tree of Dictionaries (Hashes) and Arrays that contain simpler
-values such as Integers, Reals and Strings.
-
-## TODO
-
-PDF::API2 features that are not yet available in PDF::API6 include:
-
-- Images. PDF::API6 supports PNG, JPEG and GIF images
-
-    - currently not supported are: TIFF and PNM images.
-
-- Fonts
-
-   - Synthetic fonts are NYI (wanted: module PDF::Font::Synthetic)
-
-
 # SYNOPSIS
 
 ```raku
@@ -1595,7 +1568,7 @@ links that are both internally and externally accessible.
 PDF::API6 has some basic ability to tag graphical content.
 
 See also the [PDF::Tags](https://pdf-raku.github.io/PDF-Tags-raku/) module,
-which can be used with PDF::API and provides more functionality.
+which can be used with this module and provides more functionality.
 
 ### tag
 

lib/PDF/API6.rakumod

@@ -26,6 +26,7 @@ class PDF::API6:ver<0.2.8>
     use PDF::COS::Name;
     use PDF::API6::Preferences;
     use PDF::Content::Text::Box;
+    has Lock $!lock handles<protect> .= new() ;
 
     subset PageRef where {$_ ~~ UInt|Str|PDF::Page|PDF::Destination|PDF::Action::GoTo};
     sub prefix:</>($name) { PDF::COS::Name.COERCE($name) };
@@ -66,7 +67,7 @@ class PDF::API6:ver<0.2.8>
 
     has PDF::API6::Preferences $.preferences;
     method preferences {
-        $!preferences //= PDF::API6::Preferences.new: :$.catalog;
+        $.protect: { $!preferences //= PDF::API6::Preferences.new: :$.catalog };
     }
 
     #| Make a miscellaneous named destination
@@ -137,17 +138,19 @@ class PDF::API6:ver<0.2.8>
     }
     multi method action( PDF::Action::URI :$uri!) { $uri; }
 
-    method outlines is rw { self.catalog.Outlines //= {} };
+    method outlines is rw { $.protect: { self.catalog.Outlines //= %() } };
 
     method is-encrypted { ? self.Encrypt }
     method info returns PDF::Info { self.Info //= {} }
 
     has PDF::Metadata::XML $.xmp-metadata is rw;
     method xmp-metadata is rw {
-        $!xmp-metadata //= ($.catalog.Metadata //= {
-            :Type(/<Metadata>),
-            :Subtype(/<XML>),
-        });
+        $.protect: {
+            $!xmp-metadata //= ($.catalog.Metadata //= {
+                                       :Type(/<Metadata>),
+                                       :Subtype(/<XML>),
+                                   });
+        }
 
         $!xmp-metadata.decoded; # rw target
     }
@@ -235,7 +238,7 @@ class PDF::API6:ver<0.2.8>
         # final finishing hook for document. Called just prior to serializing
         if %!attachments {
             # new attachments to be added
-            my $names = $.catalog.Names //= {};
+            my $names = $.protect: { $.catalog.Names //= %() };
             with $names.EmbeddedFiles {
                 # construct a simple name tree /EmbeddedFiles entry in the Catalog. If
                 # there's an existing tree, just flatten it. Potentially expensive for