[gxml/gsoc2013: 45/69] CharacterData.vala: improve error handling, check more bounds, factor out bound checking

[Richard Hans Schwarting <rschwart src gnome org>]

commit 56d75a5800f4c8f4c4c99b25f750c95138ce7214
Author: Richard Schwarting <aquarichy gmail com>
Date:   Sat Jul 27 00:01:53 2013 -0400

    CharacterData.vala: improve error handling, check more bounds, factor out bound checking

 gxml/CharacterData.vala |   57 +++++++++++++++++++++++++++++++++++-----------
 1 files changed, 43 insertions(+), 14 deletions(-)
---
diff --git a/gxml/CharacterData.vala b/gxml/CharacterData.vala
index 5fc2449..1bca77d 100644
--- a/gxml/CharacterData.vala
+++ b/gxml/CharacterData.vala
@@ -45,9 +45,10 @@ namespace GXml {
                        get {
                                return this.node_value;
                        }
-                       internal set {
-                               // TODO: should this not be private?
-                               this.node_value = value;
+                       set {
+                               if (! this.check_read_only ()) {
+                                       this.node_value = value;
+                               }
                        }
                }
                /**
@@ -68,6 +69,31 @@ namespace GXml {
                        base (char_node, doc);
                        // TODO: if this was this (), it would recurse infinitely, maybe valac could detect 
that
                }
+
+               protected bool check_index_size (string method, int length, ulong offset, ulong? count) {
+                       if (offset < 0) {
+                               GLib.warning ("INDEX_SIZE_ERR: %s called with offset '%lu' for data of length 
'%lu'", method, offset, length);
+                               return false;
+                       }
+                       if (count < 0) {
+                               GLib.warning ("INDEX_SIZE_ERR: %s called with count '%lu'", method, count);
+                               return false;
+                       }
+                       if (count != null) {
+                               if (length < offset + count) { // < or <= ?
+                                       GLib.warning ("INDEX_SIZE_ERR: %s called with offset '%lu' and count 
'%lu' for data of length '%lu'", method, offset, count, length);
+                                       return false;
+                               }
+                       } else {
+                               if (length <= offset) { // <= or < ?
+                                       GLib.warning ("INDEX_SIZE_ERR: %s called with offset '%lu' for data 
of length '%lu'", method, offset, length);
+                                       return false;
+                               }
+                       }
+
+                       return true;
+               }
+
                /**
                 * Retrieves a substring of the character data
                 * count-characters long, starting from the character
@@ -76,8 +102,11 @@ namespace GXml {
                 * Version: DOM Level 1 Core
                 * URL: [[http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-6531BCCF]]
                 */
-               public string substring_data (ulong offset, ulong count) { // throws DomError
-                       // TODO: handle out of bounds
+               public string substring_data (ulong offset, ulong count) {
+                       if (! check_index_size ("substring_data", this.data.length, offset, count)) {
+                               return "";
+                       }
+
                        return this.data.substring ((long)offset, (long)count);
                }
                /**
@@ -96,9 +125,11 @@ namespace GXml {
                 * Version: DOM Level 1 Core
                 * URL: [[http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-3EDB695F]]
                 */
-               public void insert_data (ulong offset, string arg) /* throws DomError */ {
-                       if (offset < 0 || this.data.length <= offset) {
-                               GLib.warning ("INDEX_SIZE_ERR: insert_data called with offset %lu for data of 
length %lu", offset, this.data.length);
+               public void insert_data (ulong offset, string arg) {
+                       /* length == 5
+                          0 1 2 3 4
+                          f a n c y */
+                       if (! check_index_size ("insert_data", this.data.length, offset, null)) {
                                return;
                        }
 
@@ -111,9 +142,8 @@ namespace GXml {
                 * Version: DOM Level 1 Core
                 * URL: [[http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-7C603781]]
                 */
-               public void delete_data (ulong offset, ulong count) /* throws DomError */ {
-                       if (offset < 0 || this.data.length <= offset || count < 0 || this.data.length < 
offset + count) {
-                               GLib.warning ("INDEX_SIZE_ERR: delete_data called with offset %lu and count 
%lu for data of length %lu", offset, count, this.data.length);
+               public void delete_data (ulong offset, ulong count) {
+                       if (! check_index_size ("delete_data", this.data.length, offset, count)) {
                                return;
                        }
 
@@ -127,9 +157,8 @@ namespace GXml {
                 * Version: DOM Level 1 Core
                 * URL: [[http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-E5CBA7FB]]
                 */
-               public void replace_data (ulong offset, ulong count, string arg) /* throws DomError */ {
-                       if (offset < 0 || this.data.length <= offset || count < 0) {
-                               GLib.warning ("INDEX_SIZE_ERR: replace_data called with offset %lu and count 
%lu for data of length %lu", offset, count, this.data.length);
+               public void replace_data (ulong offset, ulong count, string arg) {
+                       if (! check_index_size ("replace_data", this.data.length, offset, count)) {
                                return;
                        }