qpdf_set_info_key, qpdf_get_info_key

ChangeLog

@@ -1,3 +1,9 @@
+2011-08-11  Jay Berkenbilt  <ejb@ql.org>
+
+	* include/qpdf/qpdf-c.h ("C"): add new methods qpdf_get_info_key
+	and qpdf_set_info_key for manipulating text fields of the /Info
+	dictionary.
+
 2011-08-10  Jay Berkenbilt  <ejb@ql.org>
 
 	* libqpdf/QPDFWriter.cc (copyEncryptionParameters): preserve

TODO

@@ -3,10 +3,6 @@
 
  * Provide an example of using replace and swap.  Maybe.
 
- * Figure out a way to update the C API with something that can
-   update dictionary keys at least with strings.  Make sure it is
-   possible to implement something akin to pdf-mod-info in C.
-
  * Add C API for writing to memory if possible
 
 General

include/qpdf/qpdf-c.h

@@ -199,18 +199,46 @@ extern "C" {
     /* Read functions below must be called after qpdf_read or
      * qpdf_read_memory. */
 
-    /* Return the version of the PDF file. */
+    /*
+     * NOTE: Functions that return char* are returning a pointer to an
+     * internal buffer that will be reused for each call to a function
+     * that returns a char*.  You must use or copy the value before
+     * calling any other qpdf library functions.
+     */
+
+    /* Return the version of the PDF file.  See warning above about
+     * functions that return char*. */
     QPDF_DLL
     char const* qpdf_get_pdf_version(qpdf_data qpdf);
 
     /* Return the user password.  If the file is opened using the
      * owner password, the user password may be retrieved using this
      * function.  If the file is opened using the user password, this
-     * function will return that user password.
+     * function will return that user password.  See warning above
+     * about functions that return char*.
      */
     QPDF_DLL
     char const* qpdf_get_user_password(qpdf_data qpdf);
 
+    /* Return the string value of a key in the document's Info
+     * dictionary.  The key parameter should include the leading
+     * slash, e.g. "/Author".  If the key is not present or has a
+     * non-string value, a null pointer is returned.  Otherwise, a
+     * pointer to an internal buffer is returned.  See warning above
+     * about functions that return char*.
+     */
+    QPDF_DLL
+    char const* qpdf_get_info_key(qpdf_data qpdf, char const* key);
+
+    /* Set a value in the info dictionary, possibly replacing an
+     * existing value.  The key must include the leading slash
+     * (e.g. "/Author").  Passing a null pointer as a value will
+     * remove the key from the info dictionary.  Otherwise, a copy
+     * will be made of the string that is passed in.
+     */
+    QPDF_DLL
+    void qpdf_set_info_key(qpdf_data qpdf, char const* key, char const* value);
+
     /* Indicate whether the input file is linearized. */
     QPDF_DLL
     QPDF_BOOL qpdf_is_linearized(qpdf_data qpdf);

libqpdf/qpdf-c.cc

@@ -8,6 +8,7 @@
 #include <list>
 #include <string>
 #include <stdexcept>
+#include <cstring>
 
 struct _qpdf_error
 {
@@ -283,6 +284,64 @@ char const* qpdf_get_user_password(qpdf_data qpdf)
     return qpdf->tmp_string.c_str();
 }
 
+char const* qpdf_get_info_key(qpdf_data qpdf, char const* key)
+{
+    char const* result = 0;
+    QPDFObjectHandle trailer = qpdf->qpdf->getTrailer();
+    if (trailer.hasKey("/Info"))
+    {
+	QPDFObjectHandle info = trailer.getKey("/Info");
+	if (info.hasKey(key))
+	{
+	    QPDFObjectHandle value = info.getKey(key);
+	    if (value.isString())
+	    {
+		qpdf->tmp_string = value.getStringValue();
+		result = qpdf->tmp_string.c_str();
+	    }
+	}
+    }
+    QTC::TC("qpdf", "qpdf-c get_info_key", (result == 0 ? 0 : 1));
+    return result;
+}
+
+void qpdf_set_info_key(qpdf_data qpdf, char const* key, char const* value)
+{
+    if ((key == 0) || (std::strlen(key) == 0) || (key[0] != '/'))
+    {
+	return;
+    }
+    QPDFObjectHandle value_object;
+    if (value)
+    {
+	QTC::TC("qpdf", "qpdf-c set_info_key to value");
+	value_object = QPDFObjectHandle::newString(value);
+    }
+    else
+    {
+	QTC::TC("qpdf", "qpdf-c set_info_key to null");
+	value_object = QPDFObjectHandle::newNull();
+    }
+
+    QPDFObjectHandle trailer = qpdf->qpdf->getTrailer();
+    if (! trailer.hasKey("/Info"))
+    {
+	QTC::TC("qpdf", "qpdf-c add info to trailer");
+	trailer.replaceKey(
+	    "/Info",
+	    qpdf->qpdf->makeIndirectObject(
+		QPDFObjectHandle::newDictionary(
+		    std::map<std::string, QPDFObjectHandle>())));
+    }
+    else
+    {
+	QTC::TC("qpdf", "qpdf-c set-info-key use existing info");
+    }
+
+    QPDFObjectHandle info = trailer.getKey("/Info");
+    info.replaceOrRemoveKey(key, value_object);
+}
+
 QPDF_BOOL qpdf_is_linearized(qpdf_data qpdf)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_is_linearized");

manual/qpdf-manual.xml

@@ -2123,6 +2123,14 @@ print "\n";
         objects as vectors.
        </para>
       </listitem>
+      <listitem>
+       <para>
+        Add functions <function>qpdf_get_info_key</function> and
+        <function>qpdf_set_info_key</function> to the C API for
+        manipulating string fields of the document's
+        <literal>/Info</literal> dictionary.
+       </para>
+      </listitem>
      </itemizedlist>
     </listitem>
    </varlistentry>

qpdf/qpdf-ctest.c

@@ -325,6 +325,36 @@ static void test15(char const* infile,
     report_errors();
 }
 
+static void print_info(char const* key)
+{
+    char const* value = qpdf_get_info_key(qpdf, key);
+    printf("Info key %s: %s\n",
+	   key, (value ? value : "(null)"));
+}
+
+static void test16(char const* infile,
+		   char const* password,
+		   char const* outfile,
+		   char const* outfile2)
+{
+    qpdf_read(qpdf, infile, password);
+    print_info("/Author");
+    print_info("/Producer");
+    print_info("/Creator");
+    qpdf_set_info_key(qpdf, "/Author", "Mr. Potato Head");
+    qpdf_set_info_key(qpdf, "/Producer", "QPDF libary");
+    qpdf_set_info_key(qpdf, "/Creator", 0);
+    print_info("/Author");
+    print_info("/Producer");
+    print_info("/Creator");
+    qpdf_init_write(qpdf, outfile);
+    qpdf_set_static_ID(qpdf, QPDF_TRUE);
+    qpdf_set_static_aes_IV(qpdf, QPDF_TRUE);
+    qpdf_set_stream_data_mode(qpdf, qpdf_s_uncompress);
+    qpdf_write(qpdf);
+    report_errors();
+}
+
 int main(int argc, char* argv[])
 {
     char* p = 0;
@@ -380,6 +410,7 @@ int main(int argc, char* argv[])
 	  (n == 13) ? test13 :
 	  (n == 14) ? test14 :
 	  (n == 15) ? test15 :
+	  (n == 16) ? test16 :
 	  0);
 
     if (fn == 0)

qpdf/qpdf.testcov

@@ -194,3 +194,8 @@ QPDF stream with CRNL 0
 QPDF stream with NL only 0
 QPDF replaceObject called with indirect object 0
 QPDFWriter copy encrypt metadata 1
+qpdf-c get_info_key 1
+qpdf-c set_info_key to value 0
+qpdf-c set_info_key to null 0
+qpdf-c set-info-key use existing info 0
+qpdf-c add info to trailer 0

qpdf/qtest/qpdf.test

@@ -111,7 +111,7 @@ $td->runtest("new stream",
 show_ntests();
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 33;
+$n_tests += 37;
 
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
@@ -285,6 +285,26 @@ $td->runtest("check output",
 	     {$td->FILE => "a.pdf"},
 	     {$td->FILE => "test14-out.pdf"});
 
+$td->runtest("C API info key functions",
+	     {$td->COMMAND => "qpdf-ctest 16 minimal.pdf '' a.pdf"},
+	     {$td->FILE => "c-info1.out",
+	      $td->EXIT_STATUS => 0},
+	     $td->NORMALIZE_NEWLINES);
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "c-info-out.pdf"});
+unlink "a.pdf" or die;
+
+$td->runtest("C API info key functions",
+	     {$td->COMMAND => "qpdf-ctest 16 c-info2-in.pdf '' a.pdf"},
+	     {$td->FILE => "c-info2.out",
+	      $td->EXIT_STATUS => 0},
+	     $td->NORMALIZE_NEWLINES);
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "c-info-out.pdf"});
+unlink "a.pdf" or die;
+
 show_ntests();
 # ----------
 $td->notify("--- Error Condition Tests ---");

qpdf/qtest/qpdf/c-info-out.pdf

@@ -0,0 +1,44 @@
+%PDF-1.3
+%¿÷¢þ
+1 0 obj
+<< /Pages 3 0 R /Type /Catalog >>
+endobj
+2 0 obj
+<< /Author (Mr. Potato Head) /Producer (QPDF libary) >>
+endobj
+3 0 obj
+<< /Count 1 /Kids [ 4 0 R ] /Type /Pages >>
+endobj
+4 0 obj
+<< /Contents 5 0 R /MediaBox [ 0 0 612 792 ] /Parent 3 0 R /Resources << /Font << /F1 6 0 R >> /ProcSet 7 0 R >> /Type /Page >>
+endobj
+5 0 obj
+<< /Length 44 >>
+stream
+BT
+  /F1 24 Tf
+  72 720 Td
+  (Potato) Tj
+ET
+endstream
+endobj
+6 0 obj
+<< /BaseFont /Helvetica /Encoding /WinAnsiEncoding /Name /F1 /Subtype /Type1 /Type /Font >>
+endobj
+7 0 obj
+[ /PDF /Text ]
+endobj
+xref
+0 8
+0000000000 65535 f 
+0000000015 00000 n 
+0000000064 00000 n 
+0000000135 00000 n 
+0000000194 00000 n 
+0000000337 00000 n 
+0000000430 00000 n 
+0000000537 00000 n 
+trailer << /Info 2 0 R /Root 1 0 R /Size 8 /ID [<31415926535897932384626433832795><31415926535897932384626433832795>] >>
+startxref
+567
+%%EOF

qpdf/qtest/qpdf/c-info1.out

@@ -0,0 +1,6 @@
+Info key /Author: (null)
+Info key /Producer: (null)
+Info key /Creator: (null)
+Info key /Author: Mr. Potato Head
+Info key /Producer: QPDF libary
+Info key /Creator: (null)

qpdf/qtest/qpdf/c-info2.out

@@ -0,0 +1,6 @@
+Info key /Author: Someone Else
+Info key /Producer: Something Else
+Info key /Creator: A. Nony Mous
+Info key /Author: Mr. Potato Head
+Info key /Producer: QPDF libary
+Info key /Creator: (null)