Implement helpers for file attachments

1 files changed, 193 insertions, 0 deletions

diff --git a/libqpdf/QPDFEFStreamObjectHelper.cc b/libqpdf/QPDFEFStreamObjectHelper.cc
new file mode 100644
index 00000000..c4e64a71
--- /dev/null
+++ b/libqpdf/QPDFEFStreamObjectHelper.cc
@@ -0,0 +1,193 @@
+#include <qpdf/QPDFEFStreamObjectHelper.hh>
+#include <qpdf/QIntC.hh>
+#include <qpdf/QUtil.hh>
+#include <qpdf/Pl_Count.hh>
+#include <qpdf/Pl_MD5.hh>
+#include <qpdf/Pl_Discard.hh>
+
+QPDFEFStreamObjectHelper::QPDFEFStreamObjectHelper(
+    QPDFObjectHandle oh) :
+    QPDFObjectHelper(oh),
+    m(new Members())
+{
+}
+
+QPDFEFStreamObjectHelper::Members::Members()
+{
+}
+
+QPDFObjectHandle
+QPDFEFStreamObjectHelper::getParam(std::string const& pkey)
+{
+    auto params = this->oh.getDict().getKey("/Params");
+    if (params.isDictionary())
+    {
+        return params.getKey(pkey);
+    }
+    return QPDFObjectHandle::newNull();
+}
+
+void
+QPDFEFStreamObjectHelper::setParam(
+    std::string const& pkey, QPDFObjectHandle const& pval)
+{
+    auto params = this->oh.getDict().getKey("/Params");
+    if (! params.isDictionary())
+    {
+        params = QPDFObjectHandle::newDictionary();
+        this->oh.getDict().replaceKey("/Params", params);
+    }
+    params.replaceKey(pkey, pval);
+}
+
+std::string
+QPDFEFStreamObjectHelper::getCreationDate()
+{
+    auto val = getParam("/CreationDate");
+    if (val.isString())
+    {
+        return val.getUTF8Value();
+    }
+    return "";
+}
+
+std::string
+QPDFEFStreamObjectHelper::getModDate()
+{
+    auto val = getParam("/ModDate");
+    if (val.isString())
+    {
+        return val.getUTF8Value();
+    }
+    return "";
+}
+
+size_t
+QPDFEFStreamObjectHelper::getSize()
+{
+    auto val = getParam("/Size");
+    if (val.isInteger())
+    {
+        return QIntC::to_size(val.getUIntValueAsUInt());
+    }
+    return 0;
+}
+
+std::string
+QPDFEFStreamObjectHelper::getSubtype()
+{
+    auto val = getParam("/Subtype");
+    if (val.isName())
+    {
+        auto n = val.getName();
+        if (n.length() > 1)
+        {
+            return n.substr(1);
+        }
+    }
+    return "";
+}
+
+std::string
+QPDFEFStreamObjectHelper::getChecksum()
+{
+    auto val = getParam("/CheckSum");
+    if (val.isString())
+    {
+        return val.getStringValue();
+    }
+    return "";
+}
+
+QPDFEFStreamObjectHelper
+QPDFEFStreamObjectHelper::createEFStream(
+    QPDF& qpdf, PointerHolder<Buffer> data)
+{
+    return newFromStream(QPDFObjectHandle::newStream(&qpdf, data));
+}
+
+QPDFEFStreamObjectHelper
+QPDFEFStreamObjectHelper::createEFStream(
+    QPDF& qpdf, std::string const& data)
+{
+    return newFromStream(QPDFObjectHandle::newStream(&qpdf, data));
+}
+
+namespace QEF
+{
+    class Provider: public QPDFObjectHandle::StreamDataProvider
+    {
+      public:
+        Provider(std::function<void(Pipeline*)> provider) :
+            StreamDataProvider(false),
+            provider(provider)
+        {
+        }
+        virtual ~Provider() = default;
+        virtual void provideStreamData(int objid, int generation,
+                                       Pipeline* pipeline) override
+        {
+            this->provider(pipeline);
+        }
+
+      private:
+        std::function<void(Pipeline*)> provider;
+    };
+};
+
+QPDFEFStreamObjectHelper
+QPDFEFStreamObjectHelper::createEFStream(
+    QPDF& qpdf, std::function<void(Pipeline*)> provider)
+{
+    auto stream = QPDFObjectHandle::newStream(&qpdf);
+    stream.replaceStreamData(new QEF::Provider(provider),
+                             QPDFObjectHandle::newNull(),
+                             QPDFObjectHandle::newNull());
+    return newFromStream(stream);
+}
+
+QPDFEFStreamObjectHelper&
+QPDFEFStreamObjectHelper::setCreationDate(std::string const& date)
+{
+    setParam("/CreationDate", QPDFObjectHandle::newString(date));
+    return *this;
+}
+
+QPDFEFStreamObjectHelper&
+QPDFEFStreamObjectHelper::setModDate(std::string const& date)
+{
+    setParam("/ModDate", QPDFObjectHandle::newString(date));
+    return *this;
+}
+
+QPDFEFStreamObjectHelper&
+QPDFEFStreamObjectHelper::setSubtype(std::string const& subtype)
+{
+    setParam("/Subtype", QPDFObjectHandle::newName("/" + subtype));
+    return *this;
+}
+
+QPDFEFStreamObjectHelper
+QPDFEFStreamObjectHelper::newFromStream(QPDFObjectHandle stream)
+{
+    QPDFEFStreamObjectHelper result(stream);
+    stream.getDict().replaceKey(
+        "/Type", QPDFObjectHandle::newName("/EmbeddedFile"));
+    Pl_Discard discard;
+    Pl_MD5 md5("EF md5", &discard);
+    Pl_Count count("EF size", &md5);
+    if (! stream.pipeStreamData(&count, nullptr, 0, qpdf_dl_all))
+    {
+        stream.warnIfPossible(
+            "unable to get stream data for new embedded file stream");
+    }
+    else
+    {
+        result.setParam(
+            "/Size", QPDFObjectHandle::newInteger(count.getCount()));
+        result.setParam(
+            "/CheckSum", QPDFObjectHandle::newString(
+                QUtil::hex_decode(md5.getHexDigest())));
+    }
+    return result;
+}