[file-roller: 1/5] libarchive: add support for seek and skip methods

[Paolo Bacchilega <paobac src gnome org>]

commit 8883f4c7d9f2f9d34a6b07c01b1ee7e7bf9de7a3
Author: Peter Keresztes Schmidt <carbenium outlook com>
Date:   Tue Aug 6 04:03:39 2019 +0200

    libarchive: add support for seek and skip methods
    
    With this all read related callbacks needed by libarchive
    are implemented. This allows better support for new formats/features.

 src/fr-archive-libarchive.c | 111 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 99 insertions(+), 12 deletions(-)
---
diff --git a/src/fr-archive-libarchive.c b/src/fr-archive-libarchive.c
index 1d451648..8e8841b3 100644
--- a/src/fr-archive-libarchive.c
+++ b/src/fr-archive-libarchive.c
@@ -274,6 +274,73 @@ load_data_read (struct archive  *a,
 }
 
 
+static gint64
+load_data_seek (struct archive *a,
+               void           *client_data,
+               gint64          request,
+               int             whence)
+{
+       GSeekable *seekable;
+       GSeekType  seektype;
+       off_t new_offset;
+
+       LoadData *load_data = client_data;
+
+       seekable = (GSeekable*)(load_data->istream);
+       if (load_data->error != NULL || load_data->istream == NULL)
+       return -1;
+
+       switch (whence) {
+               case SEEK_SET:
+                       seektype = G_SEEK_SET;
+                       break;
+               case SEEK_CUR:
+                       seektype = G_SEEK_CUR;
+                       break;
+               case SEEK_END:
+                       seektype = G_SEEK_END;
+                       break;
+               default:
+                       return -1;
+       }
+
+       g_seekable_seek (seekable,
+                        request,
+                        seektype,
+                        load_data->cancellable,
+                        &load_data->error);
+       new_offset = g_seekable_tell (seekable);
+       if (load_data->error != NULL)
+               return -1;
+
+       return new_offset;
+}
+
+
+static gint64
+load_data_skip (struct archive *a,
+               void           *client_data,
+               gint64          request)
+{
+       GSeekable *seekable;
+       off_t old_offset, new_offset;
+
+       LoadData *load_data = client_data;
+
+       seekable = (GSeekable*)(load_data->istream);
+       if (load_data->error != NULL || load_data->istream == NULL)
+               return -1;
+
+       old_offset = g_seekable_tell (seekable);
+       new_offset = load_data_seek (a, client_data, request, SEEK_CUR);
+       if (new_offset > old_offset)
+               return (new_offset - old_offset);
+
+       return 0;
+}
+
+
+
 static int
 load_data_close (struct archive *a,
                 void           *client_data)
@@ -292,6 +359,25 @@ load_data_close (struct archive *a,
 }
 
 
+static int
+create_read_object (LoadData        *load_data,
+                   struct archive **a)
+{
+       *a = archive_read_new ();
+       archive_read_support_filter_all (*a);
+       archive_read_support_format_all (*a);
+
+       archive_read_set_open_callback (*a, load_data_open);
+       archive_read_set_read_callback (*a, load_data_read);
+       archive_read_set_close_callback (*a, load_data_close);
+       archive_read_set_seek_callback (*a, load_data_seek);
+       archive_read_set_skip_callback (*a, load_data_skip);
+       archive_read_set_callback_data (*a, load_data);
+
+       return archive_read_open1 (*a);
+}
+
+
 /* -- list -- */
 
 
@@ -349,10 +435,12 @@ list_archive_thread (GSimpleAsyncResult *result,
        fr_archive_progress_set_total_bytes (load_data->archive,
                                             _g_file_get_size (fr_archive_get_file (load_data->archive), 
cancellable));
 
-       a = archive_read_new ();
-       archive_read_support_filter_all (a);
-       archive_read_support_format_all (a);
-       archive_read_open (a, load_data, load_data_open, load_data_read, load_data_close);
+       r = create_read_object (load_data, &a);
+       if (r != ARCHIVE_OK) {
+               archive_read_free(a);
+               return;
+       }
+
        while ((r = archive_read_next_header (a, &entry)) == ARCHIVE_OK) {
                FileData   *file_data;
                const char *pathname;
@@ -620,15 +708,17 @@ extract_archive_thread (GSimpleAsyncResult *result,
        extract_data = g_simple_async_result_get_op_res_gpointer (result);
        load_data = LOAD_DATA (extract_data);
 
+       r = create_read_object (load_data, &a);
+       if (r != ARCHIVE_OK) {
+               archive_read_free(a);
+               return;
+       }
+
        checked_folders = g_hash_table_new_full (g_file_hash, (GEqualFunc) g_file_equal, g_object_unref, 
NULL);
        created_files = g_hash_table_new_full (g_file_hash, (GEqualFunc) g_file_equal, g_object_unref, 
g_object_unref);
        folders_created_during_extraction = g_hash_table_new_full (g_file_hash, (GEqualFunc) g_file_equal, 
g_object_unref, NULL);
        fr_archive_progress_set_total_files (load_data->archive, extract_data->n_files_to_extract);
 
-       a = archive_read_new ();
-       archive_read_support_filter_all (a);
-       archive_read_support_format_all (a);
-       archive_read_open (a, load_data, load_data_open, load_data_read, load_data_close);
        while ((r = archive_read_next_header (a, &entry)) == ARCHIVE_OK) {
                const char    *pathname;
                char          *fullpath;
@@ -1436,10 +1526,7 @@ save_archive_thread (GSimpleAsyncResult *result,
        archive_write_open (b, save_data, save_data_open, save_data_write, save_data_close);
        archive_write_set_bytes_in_last_block (b, 1);
 
-       a = archive_read_new ();
-       archive_read_support_filter_all (a);
-       archive_read_support_format_all (a);
-       archive_read_open (a, load_data, load_data_open, load_data_read, load_data_close);
+       create_read_object (load_data, &a);
 
        if (save_data->begin_operation != NULL)
                save_data->begin_operation (save_data, save_data->user_data);