Implement helpers for file attachments

1 files changed, 146 insertions, 0 deletions

diff --git a/libqpdf/QPDFEmbeddedFileDocumentHelper.cc b/libqpdf/QPDFEmbeddedFileDocumentHelper.cc
new file mode 100644
index 00000000..6348529d
--- /dev/null
+++ b/libqpdf/QPDFEmbeddedFileDocumentHelper.cc
@@ -0,0 +1,146 @@
+#include <qpdf/QPDFEmbeddedFileDocumentHelper.hh>
+
+// File attachments are stored in the /EmbeddedFiles (name tree) key
+// of the /Names dictionary from the document catalog. Each entry
+// points to a /FileSpec, which in turn points to one more Embedded
+// File Streams. Note that file specs can appear in other places as
+// well, such as file attachment annotations, among others.
+//
+// root -> /Names -> /EmbeddedFiles = name tree
+// filename -> filespec
+// <<
+//   /Desc ()
+//   /EF <<
+//     /F x 0 R
+//     /UF x 0 R
+//   >>
+//   /F (name)
+//   /UF (name)
+//   /Type /Filespec
+// >>
+// x 0 obj
+// <<
+//   /Type /EmbeddedFile
+//   /DL filesize % not in spec?
+//   /Params <<
+//     /CheckSum <md5>
+//     /CreationDate (D:yyyymmddhhmmss{-hh'mm'|+hh'mm'|Z})
+//     /ModDate (D:yyyymmddhhmmss-hh'mm')
+//     /Size filesize
+//     /Subtype /mime#2ftype
+//   >>
+// >>
+
+QPDFEmbeddedFileDocumentHelper::QPDFEmbeddedFileDocumentHelper(QPDF& qpdf) :
+    QPDFDocumentHelper(qpdf),
+    m(new Members())
+{
+    auto root = qpdf.getRoot();
+    auto names = root.getKey("/Names");
+    if (names.isDictionary())
+    {
+        auto embedded_files = names.getKey("/EmbeddedFiles");
+        if (embedded_files.isDictionary())
+        {
+            this->m->embedded_files =
+                std::make_shared<QPDFNameTreeObjectHelper>(
+                    embedded_files, qpdf);
+        }
+    }
+}
+
+QPDFEmbeddedFileDocumentHelper::Members::Members()
+{
+}
+
+bool
+QPDFEmbeddedFileDocumentHelper::hasEmbeddedFiles() const
+{
+    return (this->m->embedded_files.get() != nullptr);
+}
+
+void
+QPDFEmbeddedFileDocumentHelper::initEmbeddedFiles()
+{
+    if (hasEmbeddedFiles())
+    {
+        return;
+    }
+    auto root = qpdf.getRoot();
+    auto names = root.getKey("/Names");
+    if (! names.isDictionary())
+    {
+        names = QPDFObjectHandle::newDictionary();
+        root.replaceKey("/Names", names);
+    }
+    auto embedded_files = names.getKey("/EmbeddedFiles");
+    if (! embedded_files.isDictionary())
+    {
+        auto nth = QPDFNameTreeObjectHelper::newEmpty(this->qpdf);
+        names.replaceKey("/EmbeddedFiles", nth.getObjectHandle());
+        this->m->embedded_files =
+            std::make_shared<QPDFNameTreeObjectHelper>(nth);
+    }
+}
+
+std::shared_ptr<QPDFFileSpecObjectHelper>
+QPDFEmbeddedFileDocumentHelper::getEmbeddedFile(std::string const& name)
+{
+    std::shared_ptr<QPDFFileSpecObjectHelper> result;
+    if (this->m->embedded_files)
+    {
+        auto i = this->m->embedded_files->find(name);
+        if (i != this->m->embedded_files->end())
+        {
+            result = std::make_shared<QPDFFileSpecObjectHelper>(i->second);
+        }
+    }
+    return result;
+}
+
+std::map<std::string, std::shared_ptr<QPDFFileSpecObjectHelper>>
+QPDFEmbeddedFileDocumentHelper::getEmbeddedFiles()
+{
+    std::map<std::string,
+             std::shared_ptr<QPDFFileSpecObjectHelper>> result;
+    if (this->m->embedded_files)
+    {
+        for (auto const& i: *(this->m->embedded_files))
+        {
+            result[i.first] = std::make_shared<QPDFFileSpecObjectHelper>(
+                i.second);
+        }
+    }
+    return result;
+}
+
+void
+QPDFEmbeddedFileDocumentHelper::replaceEmbeddedFile(
+    std::string const& name, QPDFFileSpecObjectHelper const& fs)
+{
+    initEmbeddedFiles();
+    this->m->embedded_files->insert(
+        name, fs.getObjectHandle());
+}
+
+bool
+QPDFEmbeddedFileDocumentHelper::removeEmbeddedFile(std::string const& name)
+{
+    if (! hasEmbeddedFiles())
+    {
+        return false;
+    }
+    auto iter = this->m->embedded_files->find(name);
+    if (iter == this->m->embedded_files->end())
+    {
+        return false;
+    }
+    auto oh = iter->second;
+    iter.remove();
+    if (oh.isIndirect())
+    {
+        this->qpdf.replaceObject(oh.getObjGen(), QPDFObjectHandle::newNull());
+    }
+
+    return true;
+}