[gnome-games] dreamcast: Use StringInputStream in DreamcastHeader

[Adrien Plazas <aplazas src gnome org>]

commit ecc141d3cc4cee72d2f72a7b25fabfd747cc9c76
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Thu Jul 28 16:55:45 2016 +0200

    dreamcast: Use StringInputStream in DreamcastHeader
    
    This makes the code easier to read and avoid duplication.

 plugins/dreamcast/src/dreamcast-header.vala |   92 ++++-----------------------
 1 files changed, 13 insertions(+), 79 deletions(-)
---
diff --git a/plugins/dreamcast/src/dreamcast-header.vala b/plugins/dreamcast/src/dreamcast-header.vala
index bd6f7ba..889d0f8 100644
--- a/plugins/dreamcast/src/dreamcast-header.vala
+++ b/plugins/dreamcast/src/dreamcast-header.vala
@@ -19,25 +19,27 @@ private class Games.DreamcastHeader : Object {
                this.file = file;
        }
 
-       public void check_validity () throws DreamcastError {
+       public void check_validity () throws Error {
                // Getting the header offset needs to look for the header, and hence
                // check the validity of the file.
                get_header_offset ();
        }
 
-       public string get_product_number () throws DreamcastError {
-               var product_number = get_string_at_offset (PRODUCT_NUMBER_OFFSET, PRODUCT_NUMBER_SIZE);
+       public string get_product_number () throws Error {
+               var stream = new StringInputStream (file);
+               var product_number = stream.read_string_for_size (PRODUCT_NUMBER_OFFSET, PRODUCT_NUMBER_SIZE);
 
                return product_number.strip ();
        }
 
-       public string get_areas () throws DreamcastError {
-               var areas = get_string_at_offset (AREAS_OFFSET, AREAS_SIZE);
+       public string get_areas () throws Error {
+               var stream = new StringInputStream (file);
+               var areas = stream.read_string_for_size (AREAS_OFFSET, AREAS_SIZE);
 
                return areas.strip ();
        }
 
-       private size_t get_header_offset () throws DreamcastError {
+       private size_t get_header_offset () throws Error {
                if (header_offset != null)
                        return header_offset;
 
@@ -54,85 +56,17 @@ private class Games.DreamcastHeader : Object {
                return header_offset;
        }
 
-       private bool lookup_header_offset (size_t offset) throws DreamcastError {
-               var stream = get_stream ();
-               try {
-                       stream.seek (offset + MAGIC_OFFSET, SeekType.SET);
-               }
-               catch (Error e) {
-                       throw new DreamcastError.INVALID_SIZE (_("Invalid Dreamcast header size: %s"), 
e.message);
-               }
-
-               // The header must start with $MAGIC_VALUE.
-               var buffer = new uint8[MAGIC_VALUE.length];
-               try {
-                       stream.read (buffer);
-               }
-               catch (Error e) {
-                       throw new DreamcastError.INVALID_SIZE (e.message);
-               }
-
-               var magic = (string) buffer;
-
-               if (magic != MAGIC_VALUE)
+       private bool lookup_header_offset (size_t offset) throws Error {
+               var stream = new StringInputStream (file);
+               if (!stream.has_string (offset + MAGIC_OFFSET, MAGIC_VALUE))
                        return false;
 
-               try {
-                       stream.seek (offset + MAGIC_OFFSET, SeekType.SET);
-               }
-               catch (Error e) {
-                       throw new DreamcastError.INVALID_SIZE (_("Invalid Dreamcast header size: %s"), 
e.message);
-               }
-
-               // The header must be $HEADER_SIZE ASCII characters long.
-               buffer = new uint8[HEADER_SIZE];
-               try {
-                       stream.read (buffer);
-               }
-               catch (Error e) {
-                       throw new DreamcastError.INVALID_SIZE (e.message);
-               }
-
-               var header = (string) buffer;
-
-               return (header.length == buffer.length) && header.is_ascii ();
-       }
-
-       private string get_string_at_offset (size_t offset, size_t size) throws DreamcastError {
-               var header_offset = get_header_offset ();
-               var stream = get_stream ();
-               try {
-                       stream.seek (header_offset + offset, SeekType.SET);
-               }
-               catch (Error e) {
-                       throw new DreamcastError.INVALID_SIZE (_("Invalid Dreamcast header size: %s"), 
e.message);
-               }
-
-               var buffer = new uint8[size];
-               try {
-                       stream.read (buffer);
-               }
-               catch (Error e) {
-                       throw new DreamcastError.INVALID_HEADER (_("The file doesn't have a Dreamcast 
header."));
-               }
-
-               return (string) buffer;
-       }
+               var header = stream.read_string_for_size (offset + MAGIC_OFFSET, HEADER_SIZE);
 
-       private FileInputStream get_stream () throws DreamcastError {
-               try {
-                       return file.read ();
-               }
-               catch (Error e) {
-                       throw new DreamcastError.CANT_READ_FILE (_("Couldn't read file: %s"), e.message);
-               }
+               return header.length == HEADER_SIZE && header.is_ascii ();
        }
 }
 
 errordomain Games.DreamcastError {
-       CANT_READ_FILE,
-       INVALID_SIZE,
        INVALID_HEADER,
-       INVALID_DATE,
-       INVALID_DISK_INFO,
 }