#539: Make registration of namespaces actually work (Vladimir Nadvornik, S M Ryan)

doc/cmdxmp.txt

@@ -54,6 +54,9 @@ set Xmp.tiff.ImageDescription lang=de-DE TIFF Bildbeschreibung
 # Register a namespace which Exiv2 doesn't know yet with a prefix.
 reg ns myNamespace/
 
+# Add a property in the new custom namespace.
+set Xmp.ns.myProperty myValue
+
 # There are no built-in Exiv2 value types for structures, qualifiers and
 # nested types. However, these can be added by using an XmpText value and a
 # path as the key.
@@ -65,7 +68,7 @@ set Xmp.xmpDM.videoFrameSize/stDim:unit inch
 
 # Add an element with a qualifier (using the namespace registered earlier)
 set Xmp.dc.publisher James Bond
-set Xmp.dc.publisher/?ns:role secret agent
+set Xmp.dc.publisher[1]/?ns:role secret agent
 
 # Add a qualifer to an array element of Xmp.dc.creator (added above)
 set Xmp.dc.creator[2]/?ns:role programmer

samples/xmpsample.cpp

@@ -75,6 +75,10 @@ try {
     // image, namespaces are decoded and registered at the same time.
     Exiv2::XmpProperties::registerNs("myNamespace/", "ns");
 
+    // -------------------------------------------------------------------------
+    // Add a property in the new custom namespace.
+    xmpData["Xmp.ns.myProperty"] = "myValue";
+
     // -------------------------------------------------------------------------
     // There are no specialized values for structures, qualifiers and nested
     // types. However, these can be added by using an XmpTextValue and a path as

src/actions.cpp

@@ -1413,7 +1413,7 @@ namespace Action {
             std::cout << _("Reg ") << modifyCmd.key_ << "=\"" 
                       << modifyCmd.value_ << "\"" << std::endl;
         }
-        Exiv2::XmpProperties::registerNs(modifyCmd.value_, modifyCmd.key_);
+        // Registration has been done immediately after parsing the command.
     }
 
     Modify::AutoPtr Modify::clone() const

src/exiv2.cpp

@@ -1015,6 +1015,12 @@ namespace {
         modifyCmd.explicitType_ = explicitType;
         modifyCmd.value_ = value;
 
+        if (cmdId == reg) {
+            // Registration needs to be done immediately as the new namespaces are
+            // looked up during parsing of subsequent lines (to validate XMP keys).
+            Exiv2::XmpProperties::registerNs(modifyCmd.value_, modifyCmd.key_);
+        }
+
         return true;
     } // parseLine
 

src/properties.cpp

@@ -43,6 +43,8 @@ EXIV2_RCSID("@(#) $Id$")
 #include <iostream>
 #include <iomanip>
 #include <sstream>
+#include <cstring>
+#include <cstdlib>
 
 // *****************************************************************************
 // class member definitions
@@ -812,16 +814,57 @@ namespace Exiv2 {
 
     XmpProperties::NsRegistry XmpProperties::nsRegistry_;
 
+    const XmpNsInfo* XmpProperties::lookupNsRegistry(const XmpNsInfo::Prefix& prefix)
+    {
+        for (NsRegistry::const_iterator i = nsRegistry_.begin();
+             i != nsRegistry_.end(); ++i) {
+            if (i->second == prefix) return &(i->second);
+        }
+        return 0;
+    }
+
     void XmpProperties::registerNs(const std::string& ns,
                                    const std::string& prefix)
     {
         std::string ns2 = ns;
         if (   ns2.substr(ns2.size() - 1, 1) != "/"
             && ns2.substr(ns2.size() - 1, 1) != "#") ns2 += "/";
-        nsRegistry_[ns2] = prefix;
+        // Allocated memory is freed when the namespace is unregistered.
+        // Using malloc/free for better system compatibility in case
+        // users don't unregister their namespaces explicitely.
+        XmpNsInfo xn;
+        char* c = static_cast<char*>(std::malloc(ns2.size() + 1));
+        std::strcpy(c, ns2.c_str());
+        xn.ns_ = c;
+        c = static_cast<char*>(std::malloc(prefix.size() + 1));
+        std::strcpy(c, prefix.c_str());
+        xn.prefix_ = c;
+        xn.xmpPropertyInfo_ = 0;
+        xn.desc_ = "";
+        nsRegistry_[ns2] = xn;
         XmpParser::registerNs(ns2, prefix);
     }
 
+    void XmpProperties::unregisterNs(const std::string& ns)
+    {
+        NsRegistry::iterator i = nsRegistry_.find(ns);
+        if (i != nsRegistry_.end()) {
+            XmpParser::unregisterNs(ns);
+            std::free(const_cast<char*>(i->second.prefix_));
+            std::free(const_cast<char*>(i->second.ns_));
+            nsRegistry_.erase(i);
+        }
+    }
+
+    void XmpProperties::unregisterNs()
+    {
+        NsRegistry::iterator i = nsRegistry_.begin();
+        while (i != nsRegistry_.end()) {
+            NsRegistry::iterator kill = i++;
+            unregisterNs(kill->first);
+        }
+    }
+
     std::string XmpProperties::prefix(const std::string& ns)
     {
         std::string ns2 = ns;
@@ -829,7 +872,7 @@ namespace Exiv2 {
         NsRegistry::const_iterator i = nsRegistry_.find(ns2);
         std::string p;
         if (i != nsRegistry_.end()) {
-            p = i->second;
+            p = i->second.prefix_;
         }
         else {
             const XmpNsInfo* xn = find(xmpNsInfo, XmpNsInfo::Ns(ns2));
@@ -840,13 +883,8 @@ namespace Exiv2 {
 
     std::string XmpProperties::ns(const std::string& prefix)
     {
-        std::string n;
+        const XmpNsInfo* xn = lookupNsRegistry(XmpNsInfo::Prefix(prefix));
-        for (NsRegistry::const_iterator i = nsRegistry_.begin();
+        if (xn != 0) return xn->ns_;
-             i != nsRegistry_.end(); ++i) {
-            if (i->second == prefix) {
-                return i->first;
-            }
-        }
         return nsInfo(prefix)->ns_;
     }
 
@@ -894,7 +932,9 @@ namespace Exiv2 {
 
     const XmpNsInfo* XmpProperties::nsInfo(const std::string& prefix)
     {
-        const XmpNsInfo* xn = find(xmpNsInfo, XmpNsInfo::Prefix(prefix));
+        const XmpNsInfo::Prefix pf(prefix);
+        const XmpNsInfo* xn = lookupNsRegistry(pf);
+        if (!xn) xn = find(xmpNsInfo, pf);
         if (!xn) throw Error(35, prefix);
         return xn;
     }

src/properties.hpp

@@ -181,13 +181,33 @@ namespace Exiv2 {
           @brief Register namespace \em ns with preferred prefix \em prefix.
 
           If the namespace is a known or previously registered namespace, the
-          prefix is overwritten. This also invalidates XMP keys generated with
+          prefix is overwritten.
-          the previous prefix.
+
+          @note This invalidates XMP keys generated with the previous prefix.
          */
         static void registerNs(const std::string& ns, const std::string& prefix);
+        /*!
+          @brief Unregister a custom namespace \em ns.
+
+          The function only has an effect if there is a namespace \em ns
+          registered earlier, it does not unregister built-in namespaces.
+
+          @note This invalidates XMP keys generated in this namespace.
+         */
+        static void unregisterNs(const std::string& ns);
+        /*!
+          @brief Unregister all custom namespaces.
+
+          The function only unregisters namespaces registered earlier, it does not
+          unregister built-in namespaces.
+
+          @note This invalidates XMP keys generated in any custom namespace.
+         */
+        static void unregisterNs();
 
     private:
-        typedef std::map<std::string, std::string> NsRegistry;
+        typedef std::map<std::string, XmpNsInfo> NsRegistry;
+        static const XmpNsInfo* lookupNsRegistry(const XmpNsInfo::Prefix& prefix);
         static NsRegistry nsRegistry_;
 
     }; // class XmpProperties

src/xmp.cpp

@@ -371,6 +371,7 @@ namespace Exiv2 {
 
     void XmpParser::terminate()
     {
+        XmpProperties::unregisterNs();
         if (initialized_) {
 #ifdef EXV_HAVE_XMP_TOOLKIT
             SXMPMeta::Terminate();
@@ -394,7 +395,20 @@ namespace Exiv2 {
         initialize();
         return true;
 #endif
-	} // XmpParser::registerNs
+    } // XmpParser::registerNs
+
+    void XmpParser::unregisterNs(const std::string& ns)
+    {
+#ifdef EXV_HAVE_XMP_TOOLKIT
+        try {
+// Throws XMP Toolkit error 8: Unimplemented method XMPMeta::DeleteNamespace
+//          SXMPMeta::DeleteNamespace(ns.c_str());
+        }
+        catch (const XMP_Error& e) {
+            throw Error(40, e.GetID(), e.GetErrMsg());
+        }
+#endif
+    } // XmpParser::unregisterNs
 
 #ifdef EXV_HAVE_XMP_TOOLKIT
     int XmpParser::decode(      XmpData&     xmpData,

src/xmp.hpp

@@ -257,6 +257,7 @@ namespace Exiv2 {
      */
     class XmpParser {
         friend void XmpProperties::registerNs(const std::string&, const std::string&);
+        friend void XmpProperties::unregisterNs(const std::string&);
     public:
         /*!
           @brief Decode XMP metadata from an XMP packet \em xmpPacket into
@@ -299,7 +300,7 @@ namespace Exiv2 {
          */
         static bool initialize();
         /*!
-          @brief Terminate the XMP Toolkit.
+          @brief Terminate the XMP Toolkit and unregister custom namespaces.
 
           Call this method when the XmpParser is no longer needed to
           allow the XMP Toolkit to cleanly shutdown.
@@ -316,6 +317,12 @@ namespace Exiv2 {
          */
         static bool registerNs(const std::string& ns,
                                const std::string& prefix);
+        /*!
+          @brief Delete a namespace from the XMP Toolkit.
+
+          XmpProperties::unregisterNs calls this to synchronize namespaces.
+        */
+        static void unregisterNs(const std::string& ns);
 
         // DATA
         static bool initialized_; //! Indicates if the XMP Toolkit has been initialized

test/data/cmdxmp.txt

@@ -54,6 +54,9 @@ set Xmp.tiff.ImageDescription lang=de-DE TIFF Bildbeschreibung
 # Register a namespace which Exiv2 doesn't know yet with a prefix.
 reg ns myNamespace/
 
+# Add a property in the new custom namespace.
+set Xmp.ns.myProperty myValue
+
 # There are no built-in Exiv2 value types for structures, qualifiers and
 # nested types. However, these can be added by using an XmpText value and a
 # path as the key.
@@ -65,7 +68,7 @@ set Xmp.xmpDM.videoFrameSize/stDim:unit inch
 
 # Add an element with a qualifier (using the namespace registered earlier)
 set Xmp.dc.publisher James Bond
-set Xmp.dc.publisher/?ns:role secret agent
+set Xmp.dc.publisher[1]/?ns:role secret agent
 
 # Add a qualifer to an array element of Xmp.dc.creator (added above)
 set Xmp.dc.creator[2]/?ns:role programmer

test/data/xmpparser-test.out

@@ -293,6 +293,7 @@ Xmp.dc.format                                XmpText    10  image/jpeg
 Xmp.dc.creator                               XmpSeq      3  1) The first creator, 2) The second creator, 3) And another one
 Xmp.dc.description                           LangAlt     2  lang="x-default" Hello, World, lang="de-DE" Hallo, Welt
 Xmp.tiff.ImageDescription                    LangAlt     2  lang="x-default" TIFF image description, lang="de-DE" TIFF Bildbeschreibung
+Xmp.ns.myProperty                            XmpText     7  myValue
 Xmp.xmpDM.videoFrameSize/stDim:w             XmpText     2  16
 Xmp.xmpDM.videoFrameSize/stDim:h             XmpText     1  9
 Xmp.xmpDM.videoFrameSize/stDim:unit          XmpText     4  inch
@@ -323,7 +324,8 @@ Xmp.xmpBJ.JobRef[2]/stJob:role               XmpText     8  Best man
    dc:five="256"
    dc:six="false"
    dc:seven="Seven"
-   dc:format="image/jpeg">
+   dc:format="image/jpeg"
+   ns:myProperty="myValue">
    <dc:subject>
     <rdf:Bag>
      <rdf:li>Palmtree</rdf:li>
@@ -427,11 +429,12 @@ Set Xmp.dc.description "Hello, World" (LangAlt)
 Set Xmp.tiff.ImageDescription "TIFF image description" (LangAlt)
 Set Xmp.tiff.ImageDescription "lang=de-DE TIFF Bildbeschreibung" (LangAlt)
 Reg ns="myNamespace/"
+Set Xmp.ns.myProperty "myValue" (XmpText)
 Set Xmp.xmpDM.videoFrameSize/stDim:w "16" (XmpText)
 Set Xmp.xmpDM.videoFrameSize/stDim:h "9" (XmpText)
 Set Xmp.xmpDM.videoFrameSize/stDim:unit "inch" (XmpText)
 Set Xmp.dc.publisher "James Bond" (XmpBag)
-Set Xmp.dc.publisher/?ns:role "secret agent" (XmpText)
+Set Xmp.dc.publisher[1]/?ns:role "secret agent" (XmpText)
 Set Xmp.dc.creator[2]/?ns:role "programmer" (XmpText)
 Set Xmp.xmpBJ.JobRef "type=Bag" (XmpText)
 Set Xmp.xmpBJ.JobRef[1]/stJob:name "Birthday party" (XmpText)
@@ -457,8 +460,9 @@ Xmp.dc.creator[2]/?ns:role                   XmpText    10  programmer
 Xmp.dc.creator[3]                            XmpText    18  3) And another one
 Xmp.dc.description                           LangAlt     2  lang="x-default" Hello, World, lang="de-DE" Hallo, Welt
 Xmp.dc.publisher                             XmpText     0  type="Bag"
-Xmp.dc.publisher/?ns:role                    XmpText    12  secret agent
 Xmp.dc.publisher[1]                          XmpText    10  James Bond
+Xmp.dc.publisher[1]/?ns:role                 XmpText    12  secret agent
+Xmp.ns.myProperty                            XmpText     7  myValue
 Xmp.tiff.ImageDescription                    LangAlt     2  lang="x-default" TIFF image description, lang="de-DE" TIFF Bildbeschreibung
 Xmp.xmpDM.videoFrameSize                     XmpText     0  type="Struct"
 Xmp.xmpDM.videoFrameSize/stDim:w             XmpText     2  16