From f1abbf33f255fcc9b452eb773a2de49972d5c370 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luk=C3=A1=C5=A1=20Lalinsk=C3=BD?= <lalinsky@gmail.com>
Date: Sat, 31 Oct 2009 08:59:40 +0000
Subject: [PATCH] A little more complex checking for broken files

git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@1042948 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
---
 taglib/mp4/mp4atom.cpp | 12 +++++++++---
 taglib/mp4/mp4file.cpp | 20 ++++++++++++++++++++
 taglib/mp4/mp4file.h   |  1 +
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/taglib/mp4/mp4atom.cpp b/taglib/mp4/mp4atom.cpp
index 25007946..6d86a6e5 100644
--- a/taglib/mp4/mp4atom.cpp
+++ b/taglib/mp4/mp4atom.cpp
@@ -47,7 +47,7 @@ MP4::Atom::Atom(File *file)
   if (header.size() != 8) {
     // The atom header must be 8 bytes long, otherwise there is either
     // trailing garbage or the file is truncated
-    debug("MP4: Expected 8 bytes of atom header");
+    debug("MP4: Couldn't read 8 bytes of data for atom header");
     length = 0;
     file->seek(0, File::End);
     return;
@@ -83,7 +83,10 @@ MP4::Atom::Atom(File *file)
         file->seek(4, File::Current);
       }
       while(file->tell() < offset + length) {
-        children.append(new MP4::Atom(file));
+        MP4::Atom *child = new MP4::Atom(file);
+        children.append(child);
+        if (child->length == 0)
+          return;
       }
       return;
     }
@@ -150,7 +153,10 @@ MP4::Atoms::Atoms(File *file)
   long end = file->tell();
   file->seek(0);
   while(file->tell() + 8 <= end) {
-    atoms.append(new MP4::Atom(file));
+    MP4::Atom *atom = new MP4::Atom(file);
+    atoms.append(atom);
+    if (atom->length == 0)
+      break;
   }
 }
 
diff --git a/taglib/mp4/mp4file.cpp b/taglib/mp4/mp4file.cpp
index 3165256c..3c996d1b 100644
--- a/taglib/mp4/mp4file.cpp
+++ b/taglib/mp4/mp4file.cpp
@@ -89,6 +89,18 @@ MP4::File::audioProperties() const
   return d->properties;
 }
 
+bool
+MP4::File::checkValid(const MP4::AtomList &list)
+{
+  for(uint i = 0; i < list.size(); i++) {
+    if(list[i]->length == 0)
+      return false;
+    if(!checkValid(list[i]->children))
+      return false;
+  }
+  return true;
+}
+
 void
 MP4::File::read(bool readProperties, Properties::ReadStyle audioPropertiesStyle)
 {
@@ -96,6 +108,11 @@ MP4::File::read(bool readProperties, Properties::ReadStyle audioPropertiesStyle)
     return;
 
   d->atoms = new Atoms(this);
+  if (!checkValid(d->atoms->atoms)) {
+    setValid(false);
+    return;
+  }
+
   d->tag = new Tag(this, d->atoms);
   if(readProperties) {
     d->properties = new Properties(this, d->atoms, audioPropertiesStyle);
@@ -105,6 +122,9 @@ MP4::File::read(bool readProperties, Properties::ReadStyle audioPropertiesStyle)
 bool
 MP4::File::save()
 {
+  if(!isValid())
+    return false;
+
   return d->tag->save();
 }
 
diff --git a/taglib/mp4/mp4file.h b/taglib/mp4/mp4file.h
index 0c09c04e..333551a9 100644
--- a/taglib/mp4/mp4file.h
+++ b/taglib/mp4/mp4file.h
@@ -90,6 +90,7 @@ namespace TagLib {
     private:
 
       void read(bool readProperties, Properties::ReadStyle audioPropertiesStyle);
+      bool checkValid(const MP4::AtomList &list);
 
       class FilePrivate;
       FilePrivate *d;