Implement changes suggested by Zarko and our subsequent conversations:

 - Add a way to set the minimum PDF version
 - Add a way to force the PDF version
 - Have isEncrypted return true if an /Encrypt dictionary exists even
   when we can't read the file
 - Allow qpdf_init_write to be called multiple times
 - Update some comments in headers


git-svn-id: svn+q:///qpdf/trunk@748 71b93d88-0707-0410-a8cf-f5a4172ac649

3 files changed, 64 insertions, 12 deletions

diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 4191e906..0ede7889 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -100,6 +100,37 @@ QPDFWriter::setQDFMode(bool val)
 }
 
 void
+QPDFWriter::setMinimumPDFVersion(std::string const& version)
+{
+    bool set_version = false;
+    if (this->min_pdf_version.empty())
+    {
+	set_version = true;
+    }
+    else
+    {
+	float v = atof(version.c_str());
+	float mv = atof(this->min_pdf_version.c_str());
+	if (v > mv)
+	{
+	    QTC::TC("qpdf", "QPDFWriter increasing minimum version");
+	    set_version = true;
+	}
+    }
+
+    if (set_version)
+    {
+	this->min_pdf_version = version;
+    }
+}
+
+void
+QPDFWriter::forcePDFVersion(std::string const& version)
+{
+    this->forced_pdf_version = version;
+}
+
+void
 QPDFWriter::setStaticID(bool val)
 {
     this->static_id = val;
@@ -147,7 +178,7 @@ QPDFWriter::setR2EncryptionParameters(
 	clear.insert(6);
     }
 
-    this->min_pdf_version = "1.3";
+    setMinimumPDFVersion("1.3");
     setEncryptionParameters(user_password, owner_password, 1, 2, 5, clear);
 }
 
@@ -221,7 +252,7 @@ QPDFWriter::setR3EncryptionParameters(
 	// no default so gcc warns for missing cases
     }
 
-    this->min_pdf_version = "1.4";
+    setMinimumPDFVersion("1.4");
     setEncryptionParameters(user_password, owner_password, 2, 3, 16, clear);
 }
 
@@ -1361,7 +1392,7 @@ QPDFWriter::write()
 
     if (! this->object_stream_to_objects.empty())
     {
-	this->min_pdf_version = "1.5";
+	setMinimumPDFVersion("1.5");
     }
 
     generateID();
@@ -1417,15 +1448,12 @@ QPDFWriter::writeEncryptionDictionary()
 void
 QPDFWriter::writeHeader()
 {
-    std::string version = pdf.getPDFVersion();
-    if (! this->min_pdf_version.empty())
+    setMinimumPDFVersion(pdf.getPDFVersion());
+    std::string version = this->min_pdf_version;
+    if (! this->forced_pdf_version.empty())
     {
-	float ov = atof(version.c_str());
-	float mv = atof(this->min_pdf_version.c_str());
-	if (mv > ov)
-	{
-	    version = this->min_pdf_version;
-	}
+	QTC::TC("qpdf", "QPDFWriter using forced PDF version");
+	version = this->forced_pdf_version;
     }
 
     writeString("%PDF-");
diff --git a/libqpdf/QPDF_encryption.cc b/libqpdf/QPDF_encryption.cc
index 5d061dfd..075ab22a 100644
--- a/libqpdf/QPDF_encryption.cc
+++ b/libqpdf/QPDF_encryption.cc
@@ -289,6 +289,11 @@ QPDF::initializeEncryption()
 	return;
     }
 
+    // Go ahead and set this->encryption here.  That way, isEncrypted
+    // will return true even if there were errors reading the
+    // encryption dictionary.
+    this->encrypted = true;
+
     QPDFObjectHandle id_obj = this->trailer.getKey("/ID");
     if (! (id_obj.isArray() &&
 	   (id_obj.getArrayNItems() == 2) &&
@@ -377,7 +382,6 @@ QPDF::initializeEncryption()
 	throw QPDFExc(this->file.getName() + ": invalid password");
     }
 
-    this->encrypted = true;
     this->encryption_key = compute_encryption_key(this->user_password, data);
 }
 
diff --git a/libqpdf/qpdf-c.cc b/libqpdf/qpdf-c.cc
index 9e2d0cbf..966d3dbb 100644
--- a/libqpdf/qpdf-c.cc
+++ b/libqpdf/qpdf-c.cc
@@ -252,6 +252,12 @@ DLL_EXPORT
 QPDF_ERROR_CODE qpdf_init_write(qpdf_data qpdf, char const* filename)
 {
     QPDF_ERROR_CODE status = QPDF_SUCCESS;
+    if (qpdf->qpdf_writer)
+    {
+	QTC::TC("qpdf", "qpdf-c called qpdf_init_write multiple times");
+	delete qpdf->qpdf_writer;
+	qpdf->qpdf_writer = 0;
+    }
     try
     {
 	qpdf->qpdf_writer = new QPDFWriter(*(qpdf->qpdf), filename);
@@ -391,6 +397,20 @@ void qpdf_set_linearization(qpdf_data qpdf, QPDF_BOOL value)
 }
 
 DLL_EXPORT
+void qpdf_set_minimum_pdf_version(qpdf_data qpdf, char const* version)
+{
+    QTC::TC("qpdf", "qpdf-c called qpdf_set_minimum_pdf_version");
+    qpdf->qpdf_writer->setMinimumPDFVersion(version);
+}
+
+DLL_EXPORT
+void qpdf_force_pdf_version(qpdf_data qpdf, char const* version)
+{
+    QTC::TC("qpdf", "qpdf-c called qpdf_force_pdf_version");
+    qpdf->qpdf_writer->forcePDFVersion(version);
+}
+
+DLL_EXPORT
 QPDF_ERROR_CODE qpdf_write(qpdf_data qpdf)
 {
     QPDF_ERROR_CODE status = QPDF_SUCCESS;