[pdf] Parse xml metadata to detect PDF/A documents

diff --git a/backend/pdf/ev-poppler.cc b/backend/pdf/ev-poppler.cc
index ec2bbc0835b7f01636344c939e2930d2145c09ce..24d002e079e4020d363886d8abef0062e71abc64 100644 (file)
--- a/backend/pdf/ev-poppler.cc
+++ b/backend/pdf/ev-poppler.cc
@@ -52,6 +52,11 @@
 #include "ev-attachment.h"
 #include "ev-image.h"
 
+#include <libxml/tree.h>
+#include <libxml/parser.h>
+#include <libxml/xpath.h>
+#include <libxml/xpathInternals.h>
+
 #if (defined (HAVE_POPPLER_PAGE_RENDER)) && (defined (HAVE_CAIRO_PDF) || defined (HAVE_CAIRO_PS))
 #define HAVE_CAIRO_PRINT
 #endif
@@ -573,6 +578,94 @@ pdf_document_set_password (EvDocumentSecurity *document_security,
        document->password = g_strdup (password);
 }
 
+
+/* reference:
+http://www.pdfa.org/lib/exe/fetch.php?id=pdfa%3Aen%3Atechdoc&cache=cache&media=pdfa:techdoc:tn0001_pdfa-1_and_namespaces_2008-03-18.pdf */
+static char *
+pdf_document_get_format_from_metadata (const char *metadata)
+{
+       xmlDocPtr doc;
+       xmlXPathContextPtr xpathCtx;
+       xmlXPathObjectPtr xpathObj;
+       xmlChar *part = NULL;
+       xmlChar *conf = NULL;
+       char *result = NULL;
+       int i;
+
+       doc = xmlParseMemory (metadata, strlen (metadata));
+       if (doc == NULL)
+               return NULL;      /* invalid xml metadata */
+
+       xpathCtx = xmlXPathNewContext (doc);
+       if (xpathCtx == NULL) {
+               xmlFreeDoc (doc);
+               return NULL;      /* invalid xpath context */
+       }
+
+       /* add pdf/a namespaces */
+       xmlXPathRegisterNs (xpathCtx, BAD_CAST "x", BAD_CAST "adobe:ns:meta/");
+       xmlXPathRegisterNs (xpathCtx, BAD_CAST "rdf", BAD_CAST "http://www.w3.org/1999/02/22-rdf-syntax-ns#");
+       xmlXPathRegisterNs (xpathCtx, BAD_CAST "pdfaid", BAD_CAST "http://www.aiim.org/pdfa/ns/id/");
+
+       /* reads pdf/a part */
+       /* first syntax: child node */
+       xpathObj = xmlXPathEvalExpression (BAD_CAST "/x:xmpmeta/rdf:RDF/rdf:Description/pdfaid:part", xpathCtx);
+       if (xpathObj != NULL) {
+               if (xpathObj->nodesetval != NULL && xpathObj->nodesetval->nodeNr != 0)
+                       part = xmlNodeGetContent (xpathObj->nodesetval->nodeTab[0]);
+
+               xmlXPathFreeObject (xpathObj);
+       }
+       if (part == NULL) {
+               /* second syntax: attribute */
+               xpathObj = xmlXPathEvalExpression (BAD_CAST "/x:xmpmeta/rdf:RDF/rdf:Description/@pdfaid:part", xpathCtx);
+               if (xpathObj != NULL) {
+                       if (xpathObj->nodesetval != NULL && xpathObj->nodesetval->nodeNr != 0)
+                               part = xmlNodeGetContent (xpathObj->nodesetval->nodeTab[0]);
+
+                       xmlXPathFreeObject (xpathObj);
+               }
+       }
+
+       /* reads pdf/a conformance */
+       /* first syntax: child node */
+       xpathObj = xmlXPathEvalExpression (BAD_CAST "/x:xmpmeta/rdf:RDF/rdf:Description/pdfaid:conformance", xpathCtx);
+       if (xpathObj != NULL) {
+               if (xpathObj->nodesetval != NULL && xpathObj->nodesetval->nodeNr != 0)
+                       conf = xmlNodeGetContent (xpathObj->nodesetval->nodeTab[0]);
+
+               xmlXPathFreeObject (xpathObj);
+       }
+       if (conf == NULL) {
+               /* second syntax: attribute */
+               xpathObj = xmlXPathEvalExpression (BAD_CAST "/x:xmpmeta/rdf:RDF/rdf:Description/@pdfaid:conformance", xpathCtx);
+               if (xpathObj != NULL) {
+                       if (xpathObj->nodesetval != NULL && xpathObj->nodesetval->nodeNr != 0)
+                               conf = xmlNodeGetContent (xpathObj->nodesetval->nodeTab[0]);
+
+                       xmlXPathFreeObject (xpathObj);
+               }
+       }
+
+       if (part != NULL && conf != NULL) {
+               /* makes conf lowercase */
+               for (i = 0; conf[i]; i++)
+                       conf[i] = g_ascii_tolower (conf[i]);
+
+               /* return buffer */
+               result = g_strdup_printf ("PDF/A - %s%s", part, conf);
+       }
+
+       /* Cleanup */
+       xmlFree (part);
+       xmlFree (conf);
+       xmlXPathFreeContext (xpathCtx);
+       xmlFreeDoc (doc);
+
+       return result;
+}
+
+
 static EvDocumentInfo *
 pdf_document_get_info (EvDocument *document)
 {
@@ -582,6 +675,8 @@ pdf_document_get_info (EvDocument *document)
        PopplerViewerPreferences view_prefs;
        PopplerPermissions permissions;
        EvPage *page;
+       char *metadata;
+       char *fmt;
 
        info = g_new0 (EvDocumentInfo, 1);
 
@@ -618,8 +713,18 @@ pdf_document_get_info (EvDocument *document)
                      "creation-date", &(info->creation_date),
                      "mod-date", &(info->modified_date),
                      "linearized", &(info->linearized),
+                     "metadata", &metadata,
                      NULL);
 
+       if (metadata != NULL) {
+               fmt = pdf_document_get_format_from_metadata(metadata);
+               if (fmt != NULL) {
+                       g_free (info->format);
+                       info->format = fmt;
+               }
+               g_free (metadata);
+       }
+
        info->n_pages = ev_document_get_n_pages (document);
 
        if (info->n_pages > 0) {

diff --git a/configure.ac b/configure.ac
index e84d30b8915060d6e82fae809602eb5a930e073b..0c9e38a51090caeffd4173ba80e72a3463020c29 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -357,7 +357,7 @@ AC_ARG_ENABLE(pdf,
 
 if test "x$enable_pdf" = "xyes"; then
     POPPLER_REQUIRED=0.11.0
-    PKG_CHECK_MODULES(POPPLER, poppler-glib >= $POPPLER_REQUIRED,enable_pdf=yes,enable_pdf=no)
+    PKG_CHECK_MODULES(POPPLER, poppler-glib >= $POPPLER_REQUIRED libxml-2.0 >= $LIBXML_REQUIRED,enable_pdf=yes,enable_pdf=no)
 
     if test "x$enable_pdf" = "xyes"; then
            AC_DEFINE([ENABLE_PDF], [1], [Enable pdf support.])