File API changes needed for safely passing user selected file entities from the file browser comp...

chrome/browser/extensions/extension_special_storage_policy.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_SPECIAL_STORAGE_POLICY_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SPECIAL_STORAGE_POLICY_H_
 #pragma once
 
 #include <map>
+#include <set>
 #include <string>
 
+#include "base/file_path.h"
 #include "base/synchronization/lock.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/quota/special_storage_policy.h"
 
 class Extension;
 
 // Special rights are granted to 'extensions' and 'applications'. The
 // storage subsystems and the browsing data remover query this interface
 // to determine which origins have these rights.
 class ExtensionSpecialStoragePolicy : public quota::SpecialStoragePolicy {
  public:
   ExtensionSpecialStoragePolicy();
 
   // SpecialStoragePolicy methods used by storage subsystems and the browsing
   // data remover. These methods are safe to call on any thread.
   virtual bool IsStorageProtected(const GURL& origin);
   virtual bool IsStorageUnlimited(const GURL& origin);
-  virtual bool IsLocalFileSystemAccessAllowed(const GURL& origin);
+  virtual bool IsLocalFileSystemAccessAllowed(const GURL& origin,
+                                              const FilePath& virtual_path);
+  virtual void GrantLocalFileSystemAccess(const GURL& origin,

[ericu, 2011/04/13 20:12:46]

Just looked at this again, and it doesn't look right.  A virtual path doesn't
contain origin or filesystem type information.  I don't think this has enough
information for general use [both for IsLocalFileSystemAccessAllowed and
GrantLocalFileSystemAccess].  It seems like you'd need to pass in a full URL of
the file to which you're granting access.

[zel, 2011/04/13 20:38:55]

The only reason I went with virtual part of the file was that all other
information from URL was redundant - origin is a separate param here and it's
always about local filesystem access. There is no other info in filesystem: urls
that I needed to keep a track of.  

I've felt that this approach required less memory to keep around, but I have no
problems of moving this to full filesystem: urls instead.

[ericu, 2011/04/13 22:51:27]

While I put the comment here, it's more of a big deal when you put similar
methods/params into FileSystemMountPointProvider.  There you really need either
the full URL--even the origin/type/triplet isn't enough.

It doesn't make sense to grant access to anything in the sandbox with just the
triplet--either an origin has access to its own sandbox, or it doesn't. 
However, if you were granting e.g. an extension access to a file in someone
else's sandbox, that would make sense [even though we have no plans to do that
at present].  Providing the origin of the requester and the full URL of the
target file would supply enough information for that.

+                                          const FilePath& virtual_path);
 
   // Methods used by the ExtensionService to populate this class.
   void GrantRightsForExtension(const Extension* extension);
   void RevokeRightsForExtension(const Extension* extension);
   void RevokeRightsForAllExtensions();
 
  private:
   class SpecialCollection {
    public:
     SpecialCollection();
-    ~SpecialCollection();
+    virtual ~SpecialCollection();
 
     bool Contains(const GURL& origin);
     void Add(const Extension* extension);
-    void Remove(const Extension* extension);
-    void Clear();
+    virtual void Remove(const Extension* extension);
+    virtual void Clear();
 
-   private:
+   protected:
     typedef std::map<GURL, bool> CachedResults;
     typedef std::map<std::string, scoped_refptr<const Extension> > Extensions;
     Extensions extensions_;
-    CachedResults cached_resuts_;
+    CachedResults cached_results_;
+  };
+
+  class SpecialPathCollection : public SpecialCollection {
+   public:
+    SpecialPathCollection();
+    virtual ~SpecialPathCollection();
+
+    // SpecialCollection overrides.
+    virtual void Remove(const Extension* extension);
+    virtual void Clear();
+
+    void AddPath(const GURL& origin, const FilePath& path);
+    bool ContainsPath(const GURL& origin, const FilePath& path);
+
+   private:
+    typedef std::set<FilePath> PathSet;
+    typedef std::map<const Extension*, PathSet> PathAccessMap;
+    scoped_refptr<const Extension> GetExtension(const GURL& origin);
+    PathAccessMap path_map_;
   };
 
   virtual ~ExtensionSpecialStoragePolicy();
 
   base::Lock lock_;  // Synchronize all access to the collections.
   SpecialCollection protected_apps_;
   SpecialCollection unlimited_extensions_;
-  SpecialCollection local_filesystem_extensions_;
+  SpecialPathCollection local_filesystem_extensions_;
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SPECIAL_STORAGE_POLICY_H_