[libgsf] Zip: special-case a stored "mimetype" entry.

[Morten Welinder <mortenw src gnome org>]

commit a92fd65fe806678284808ca14f0ebf48ed4a9adb
Author: Morten Welinder <terra gnome org>
Date:   Mon Dec 15 08:40:23 2014 -0500

    Zip: special-case a stored "mimetype" entry.

 ChangeLog             |    9 ++++++++
 gsf/gsf-outfile-zip.c |   54 +++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 61 insertions(+), 2 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 00349aa..858dd1d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2014-12-15  Morten Welinder  <terra gnome org>
+
+       * gsf/gsf-outfile-zip.c (special_mimetype_dirent): New function.
+       (zip_dirent_write, zip_header_write): Don't write a special unix
+       mtime field for the special mimetype entry.
+       (zip_close_root): Sort by offset.  Note: this may not be necessary
+       or even desired, but help with the zipdetails utility.
+       (zip_init_write): Make the special mimetype default to !zip64.
+
 2014-12-14  Morten Welinder  <terra gnome org>
 
        * gsf/gsf-outfile-zip.c (zip_dirent_write): Fix test for writing
diff --git a/gsf/gsf-outfile-zip.c b/gsf/gsf-outfile-zip.c
index 9d07ad7..24b305a 100644
--- a/gsf/gsf-outfile-zip.c
+++ b/gsf/gsf-outfile-zip.c
@@ -155,6 +155,23 @@ gsf_outfile_zip_seek (G_GNUC_UNUSED GsfOutput *output,
        return FALSE;
 }
 
+/*
+ * The "mimetype" member is special for ODF.  It cannot have any
+ * extra field (and thus cannot be a zip64 member).  Hardcode
+ * this to help compatibility with libgsf users depending on
+ * past behaviour of zip creation.
+ *
+ * The flip side is that such a file cannot be 4G+.
+ */
+static gboolean
+special_mimetype_dirent (const GsfZipDirent *dirent)
+{
+       return (dirent->offset == 0 &&
+               dirent->zip64 != TRUE &&
+               dirent->compr_method == GSF_ZIP_STORED &&
+               strcmp (dirent->name, "mimetype") == 0);
+}
+
 static gboolean
 zip_dirent_write (GsfOutfileZip *zip, const GsfZipDirent *dirent)
 {
@@ -200,7 +217,9 @@ zip_dirent_write (GsfOutfileZip *zip, const GsfZipDirent *dirent)
                g_string_append_len (extras, tmp, 8);
        }
 
-       if (dirent->mtime && dirent->mtime <= G_MAXUINT32) {
+       if (dirent->mtime &&
+           dirent->mtime <= G_MAXUINT32 &&
+           !special_mimetype_dirent (dirent)) {
                /* Clearly a year 2038 problem here.  */
                char tmp[4];
                GSF_LE_SET_GUINT16 (tmp, ZIP_DIRENT_EXTRA_FIELD_UNIXTIME);
@@ -306,6 +325,17 @@ zip_zip64_locator_write (GsfOutfileZip *zip, gsf_off_t trailerpos)
        return gsf_output_write (zip->sink, sizeof buf, buf);
 }
 
+static gint
+offset_ordering (gconstpointer a_, gconstpointer b_)
+{
+       GsfOutfileZip *a = *(GsfOutfileZip **)a_;
+       GsfOutfileZip *b = *(GsfOutfileZip **)b_;
+       gsf_off_t diff = a->vdir->dirent->offset - b->vdir->dirent->offset;
+
+       return diff < 0 ? -1 : diff > 0 ? +1 : 0;
+}
+
+
 static gboolean
 zip_close_root (GsfOutput *output)
 {
@@ -328,6 +358,21 @@ zip_close_root (GsfOutput *output)
                }
        }
 
+       if (1) {
+               /*
+                * It is unclear whether we need this.  However, the
+                * zipdetails utility gets utterly confused if we do
+                * not.
+                *
+                * If we do not sort, we will use the ordering in which
+                * the members were actually being written.  Note, that
+                * merely creating the member doesn't count -- it's the
+                * actual writing (or closing an empty member) that
+                * counts.
+                */
+               g_ptr_array_sort (elem, offset_ordering);
+       }
+
        /* Write directory */
        dirpos = gsf_output_tell (zip->sink);
        for (i = 0 ; i < entries ; i++) {
@@ -536,7 +581,9 @@ zip_header_write (GsfOutfileZip *zip)
                g_string_append_len (extras, tmp, 8);
        }
 
-       if (dirent->mtime && dirent->mtime <= G_MAXUINT32) {
+       if (dirent->mtime &&
+           dirent->mtime <= G_MAXUINT32 &&
+           !special_mimetype_dirent (dirent)) {
                /* Clearly a year 2038 problem here.  */
                char tmp[4];
                GSF_LE_SET_GUINT16 (tmp, ZIP_DIRENT_EXTRA_FIELD_UNIXTIME);
@@ -600,6 +647,9 @@ zip_init_write (GsfOutput *output)
        }
 
        dirent->offset = gsf_output_tell (zip->sink);
+       if (special_mimetype_dirent (dirent))
+               dirent->zip64 = FALSE;
+
        zip->vdir->dirent = dirent;
        zip_header_write (zip);
        zip->writing = TRUE;