From 3cbd3595ef8662dad9a27d5963d9327c08efb3fb Mon Sep 17 00:00:00 2001
From: John Whitington <john@coherentgraphics.co.uk>
Date: Fri, 28 Jun 2019 15:01:28 +0100
Subject: [PATCH] Plumbing for XMP metadata setting

---
 cpdf.ml        | 49 +++++++++++++++++++++++++++++++++++--------------
 cpdf.mli       |  2 +-
 cpdfcommand.ml |  9 ++++++++-
 3 files changed, 44 insertions(+), 16 deletions(-)

diff --git a/cpdf.ml b/cpdf.ml
index 495e3d2..3471763 100644
--- a/cpdf.ml
+++ b/cpdf.ml
@@ -1110,20 +1110,7 @@ let set_viewer_preference (key, value, version) pdf =
                   Pdf.trailerdict = trailerdict'}
   | None -> error "bad root"
 
-(* \section{Set an entry in the /Info dictionary} *)
-let set_pdf_info (key, value, version) pdf =
-  let infodict =
-    match Pdf.lookup_direct pdf "/Info" pdf.Pdf.trailerdict with
-    | Some d -> d
-    | None -> Pdf.Dictionary []
-  in
-    let infodict' = Pdf.add_dict_entry infodict key value in
-      let objnum = Pdf.addobj pdf infodict' in
-        pdf.Pdf.trailerdict <-
-          Pdf.add_dict_entry pdf.Pdf.trailerdict "/Info" (Pdf.Indirect objnum);
-        pdf.Pdf.minor <-
-          max pdf.Pdf.minor version;
-        pdf
+
 
 (* \section{Set page layout} *)
 let set_page_layout pdf s =
@@ -1409,6 +1396,40 @@ let print_metadata pdf =
         Printf.printf "%c" (char_of_int (bget data x))
       done
 
+(* Set XMP info *)
+let set_pdf_info_xml only_when_present (key, value, version) xmldata pdf = xmldata
+
+(* \section{Set an entry in the /Info dictionary} *)
+let set_pdf_info ?(xmp_also=false) ?(xmp_also_when_present=false) ?(xmp_just_set=false) (key, value, version) pdf =
+  let infodict =
+    match Pdf.lookup_direct pdf "/Info" pdf.Pdf.trailerdict with
+    | Some d -> d
+    | None -> Pdf.Dictionary []
+  in
+    let infodict' = Pdf.add_dict_entry infodict key value in
+      let objnum = Pdf.addobj pdf infodict' in
+        if not xmp_just_set then
+          begin
+            pdf.Pdf.trailerdict <-
+              Pdf.add_dict_entry pdf.Pdf.trailerdict "/Info" (Pdf.Indirect objnum);
+            pdf.Pdf.minor <-
+              max pdf.Pdf.minor version
+          end;
+        if xmp_also || xmp_also_when_present then
+          begin match get_metadata pdf with
+            None -> pdf
+          | Some xmldata ->
+              let pdf =
+                set_metadata_from_bytes
+                  true
+                  (set_pdf_info_xml xmp_also_when_present (key, value, version) xmldata pdf)
+                  pdf
+              in
+                pdf
+          end
+       else
+         pdf
+
 (* \section{Print font data} *)
 let list_font pdf page (name, dict) =
   let subtype =
diff --git a/cpdf.mli b/cpdf.mli
index 2bebaa0..df53565 100644
--- a/cpdf.mli
+++ b/cpdf.mli
@@ -112,7 +112,7 @@ val copy_id : bool -> Pdf.t -> Pdf.t -> Pdf.t
 
 (** [set_pdf_info (key, value, version)] sets the entry [key] in the /Info directory, updating
 the PDF minor version to [version].*)
-val set_pdf_info : (string * Pdf.pdfobject * int) -> Pdf.t -> Pdf.t
+val set_pdf_info : ?xmp_also:bool -> ?xmp_also_when_present:bool -> ?xmp_just_set:bool -> (string * Pdf.pdfobject * int) -> Pdf.t -> Pdf.t
 
 (** [set_pdf_info (key, value, version)] sets the entry [key] in the
 /ViewerPreferences directory, updating the PDF minor version to [version].*)
diff --git a/cpdfcommand.ml b/cpdfcommand.ml
index cdd05d4..0585447 100644
--- a/cpdfcommand.ml
+++ b/cpdfcommand.ml
@@ -3691,7 +3691,14 @@ let go () =
       in
         let pdf = get_single_pdf args.op false in
           let version = if args.keepversion then pdf.Pdf.minor else version in
-            write_pdf false (Cpdf.set_pdf_info (key, value, version) pdf)
+            write_pdf false
+              (Cpdf.set_pdf_info 
+                 ~xmp_also:args.alsosetxml
+                 ~xmp_also_when_present:args.alsosetxmlwhenpresent
+                 ~xmp_just_set:args.justsetxml
+                 (key, value, version) pdf)
+  | Some (SetMetadataDate date) ->
+      failwith "SetMetadataDate unimplemented"
   | Some ((HideToolbar _ | HideMenubar _ | HideWindowUI _
           | FitWindow _ | CenterWindow _ | DisplayDocTitle _) as op) ->
       begin match args.out with