Merge pull request #929 from m-holger/ogguard

Add new convenience class QPDFObjGen::Guard

6 files changed, 79 insertions, 14 deletions

diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index 03490af7..f1dcb7f7 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -1017,7 +1017,7 @@ class QPDF
       public:
         std::map<QPDFObjGen, QPDFObjectHandle> object_map;
         std::vector<QPDFObjectHandle> to_copy;
-        std::set<QPDFObjGen> visiting;
+        QPDFObjGen::set visiting;
     };
 
     class EncryptionParameters
@@ -1252,8 +1252,8 @@ class QPDF
 
     void getAllPagesInternal(
         QPDFObjectHandle cur_pages,
-        std::set<QPDFObjGen>& visited,
-        std::set<QPDFObjGen>& seen);
+        QPDFObjGen::set& visited,
+        QPDFObjGen::set& seen);
     void insertPage(QPDFObjectHandle newpage, int pos);
     void flattenPagesTree();
     void insertPageobjToPage(
@@ -1645,7 +1645,7 @@ class QPDF
         ObjUser const& ou,
         QPDFObjectHandle oh,
         std::function<int(QPDFObjectHandle&)> skip_stream_parameters,
-        std::set<QPDFObjGen>& visited,
+        QPDFObjGen::set& visited,
         bool top);
     void filterCompressedObjects(std::map<int, int> const& object_stream_data);
 
diff --git a/include/qpdf/QPDFAcroFormDocumentHelper.hh b/include/qpdf/QPDFAcroFormDocumentHelper.hh
index 4539b52d..d1ac6253 100644
--- a/include/qpdf/QPDFAcroFormDocumentHelper.hh
+++ b/include/qpdf/QPDFAcroFormDocumentHelper.hh
@@ -254,7 +254,7 @@ class QPDFAcroFormDocumentHelper: public QPDFDocumentHelper
         QPDFObjectHandle field,
         QPDFObjectHandle parent,
         int depth,
-        std::set<QPDFObjGen>& visited);
+        QPDFObjGen::set& visited);
     QPDFObjectHandle getOrCreateAcroForm();
     void adjustInheritedFields(
         QPDFObjectHandle obj,
diff --git a/include/qpdf/QPDFJob.hh b/include/qpdf/QPDFJob.hh
index 7396cd6a..51b54d80 100644
--- a/include/qpdf/QPDFJob.hh
+++ b/include/qpdf/QPDFJob.hh
@@ -571,7 +571,7 @@ class QPDFJob
 
     // JSON
     void doJSON(QPDF& pdf, Pipeline*);
-    std::set<QPDFObjGen> getWantedJSONObjects();
+    QPDFObjGen::set getWantedJSONObjects();
     void doJSONObject(
         Pipeline* p, bool& first, std::string const& key, QPDFObjectHandle&);
     void doJSONObjects(Pipeline* p, bool& first, QPDF& pdf);
diff --git a/include/qpdf/QPDFObjGen.hh b/include/qpdf/QPDFObjGen.hh
index ccab4ba2..0d14efaf 100644
--- a/include/qpdf/QPDFObjGen.hh
+++ b/include/qpdf/QPDFObjGen.hh
@@ -24,6 +24,10 @@
 
 #include <qpdf/DLL.h>
 #include <iostream>
+#include <set>
+
+class QPDFObjectHandle;
+class QPDFObjectHelper;
 
 // This class represents an object ID and generation pair.  It is
 // suitable to use as a key in a map or set.
@@ -31,6 +35,7 @@
 class QPDFObjGen
 {
   public:
+    // ABI: change to default.
     QPDF_DLL
     QPDFObjGen() :
         obj(0),
@@ -84,12 +89,72 @@ class QPDFObjGen
     QPDF_DLL
     friend std::ostream& operator<<(std::ostream& os, const QPDFObjGen& og);
 
+    // Convenience class for loop detection when processing objects.
+    //
+    // The class adds 'add' methods to a std::set<QPDFObjGen> which allows
+    // to test whether an QPDFObjGen is present in the set and to insert it in
+    // a single operation. The 'add' method is overloaded to take a QPDFObjGen,
+    // QPDFObjectHandle or an QPDFObjectHelper as parameter.
+    //
+    // The erase method is modified to ignore requests to erase
+    // QPDFObjGen(0, 0).
+    //
+    // Usage example:
+    //
+    // void process_object(QPDFObjectHandle oh, QPDFObjGen::Tracker& seen)
+    // {
+    //     if (seen.add(oh)) {
+    //         // handle first encounter of oh
+    //     } else {
+    //         // handle loop / subsequent encounter of oh
+    //     }
+    // }
+    class QPDF_DLL_CLASS set: public std::set<QPDFObjGen>
+    {
+      public:
+        // Add 'og' to the set. Return false if 'og' is already present in
+        // the set. Attempts to insert QPDFObjGen(0, 0) are ignored.
+        QPDF_DLL
+        bool
+        add(QPDFObjGen og)
+        {
+            if (og.isIndirect()) {
+                if (count(og) > 0) {
+                    return false;
+                }
+                emplace(og);
+            }
+            return true;
+        }
+
+        QPDF_DLL
+        bool add(QPDFObjectHandle const& oh);
+
+        QPDF_DLL
+        bool add(QPDFObjectHelper const& oh);
+
+        QPDF_DLL
+        void
+        erase(QPDFObjGen og)
+        {
+            if (og.isIndirect()) {
+                std::set<QPDFObjGen>::erase(og);
+            }
+        }
+
+        QPDF_DLL
+        void erase(QPDFObjectHandle const& oh);
+
+        QPDF_DLL
+        void erase(QPDFObjectHelper const& oh);
+    };
+
   private:
     // This class does not use the Members pattern to avoid a memory
     // allocation for every one of these. A lot of these get created
     // and destroyed.
-    int obj;
-    int gen;
+    int obj{0};
+    int gen{0};
 };
 
 #endif // QPDFOBJGEN_HH
diff --git a/include/qpdf/QPDFObjectHandle.hh b/include/qpdf/QPDFObjectHandle.hh
index 198ca42e..eaab6dc6 100644
--- a/include/qpdf/QPDFObjectHandle.hh
+++ b/include/qpdf/QPDFObjectHandle.hh
@@ -1611,7 +1611,7 @@ class QPDFObjectHandle
     void objectWarning(std::string const& warning);
     void assertType(char const* type_name, bool istype);
     inline bool dereference();
-    void makeDirect(std::set<QPDFObjGen>& visited, bool stop_at_streams);
+    void makeDirect(QPDFObjGen::set& visited, bool stop_at_streams);
     void disconnect();
     void setParsedOffset(qpdf_offset_t offset);
     void parseContentStream_internal(
diff --git a/include/qpdf/QPDFOutlineDocumentHelper.hh b/include/qpdf/QPDFOutlineDocumentHelper.hh
index cd11884d..38310302 100644
--- a/include/qpdf/QPDFOutlineDocumentHelper.hh
+++ b/include/qpdf/QPDFOutlineDocumentHelper.hh
@@ -22,13 +22,13 @@
 #ifndef QPDFOUTLINEDOCUMENTHELPER_HH
 #define QPDFOUTLINEDOCUMENTHELPER_HH
 
+#include <qpdf/QPDF.hh>
 #include <qpdf/QPDFDocumentHelper.hh>
 #include <qpdf/QPDFNameTreeObjectHelper.hh>
+#include <qpdf/QPDFObjGen.hh>
 #include <qpdf/QPDFOutlineObjectHelper.hh>
 
-#include <qpdf/QPDF.hh>
 #include <map>
-#include <set>
 #include <vector>
 
 #include <qpdf/DLL.h>
@@ -69,16 +69,16 @@ class QPDFOutlineDocumentHelper: public QPDFDocumentHelper
     {
         friend class QPDFOutlineObjectHelper;
 
+        // ABI: remove  QPDF_DLL and pass og by value.
         QPDF_DLL
         static bool
         checkSeen(QPDFOutlineDocumentHelper& dh, QPDFObjGen const& og)
         {
-            return dh.checkSeen(og);
+            return !dh.m->seen.add(og);
         }
     };
 
   private:
-    bool checkSeen(QPDFObjGen const& og);
     void initializeByPage();
 
     class Members
@@ -94,7 +94,7 @@ class QPDFOutlineDocumentHelper: public QPDFDocumentHelper
         Members(Members const&) = delete;
 
         std::vector<QPDFOutlineObjectHelper> outlines;
-        std::set<QPDFObjGen> seen;
+        QPDFObjGen::set seen;
         QPDFObjectHandle dest_dict;
         std::shared_ptr<QPDFNameTreeObjectHelper> names_dest;
         std::map<QPDFObjGen, std::vector<QPDFOutlineObjectHelper>> by_page;