The Tor Browser: other-licenses/snappy/src/snappy-sinksource.h@97036ab72558 (annotated)

other-licenses/snappy/src/snappy-sinksource.h@97036ab72558 (annotated)

other-licenses/snappy/src/snappy-sinksource.h

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 // Copyright 2011 Google Inc. All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
 #define UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
 #include <stddef.h>
 namespace snappy {
 // A Sink is an interface that consumes a sequence of bytes.
 class Sink {
  public:
   Sink() { }
   virtual ~Sink();
   // Append "bytes[0,n-1]" to this.
   virtual void Append(const char* bytes, size_t n) = 0;
   // Returns a writable buffer of the specified length for appending.
   // May return a pointer to the caller-owned scratch buffer which
   // must have at least the indicated length.  The returned buffer is
   // only valid until the next operation on this Sink.
   //
   // After writing at most "length" bytes, call Append() with the
   // pointer returned from this function and the number of bytes
   // written.  Many Append() implementations will avoid copying
   // bytes if this function returned an internal buffer.
   //
   // If a non-scratch buffer is returned, the caller may only pass a
   // prefix of it to Append().  That is, it is not correct to pass an
   // interior pointer of the returned array to Append().
   //
   // The default implementation always returns the scratch buffer.
   virtual char* GetAppendBuffer(size_t length, char* scratch);
  private:
   // No copying
   Sink(const Sink&);
   void operator=(const Sink&);
 };
 // A Source is an interface that yields a sequence of bytes
 class Source {
  public:
   Source() { }
   virtual ~Source();
   // Return the number of bytes left to read from the source
   virtual size_t Available() const = 0;
   // Peek at the next flat region of the source.  Does not reposition
   // the source.  The returned region is empty iff Available()==0.
   //
   // Returns a pointer to the beginning of the region and store its
   // length in *len.
   //
   // The returned region is valid until the next call to Skip() or
   // until this object is destroyed, whichever occurs first.
   //
   // The returned region may be larger than Available() (for example
   // if this ByteSource is a view on a substring of a larger source).
   // The caller is responsible for ensuring that it only reads the
   // Available() bytes.
   virtual const char* Peek(size_t* len) = 0;
   // Skip the next n bytes.  Invalidates any buffer returned by
   // a previous call to Peek().
   // REQUIRES: Available() >= n
   virtual void Skip(size_t n) = 0;
  private:
   // No copying
   Source(const Source&);
   void operator=(const Source&);
 };
 // A Source implementation that yields the contents of a flat array
 class ByteArraySource : public Source {
  public:
   ByteArraySource(const char* p, size_t n) : ptr_(p), left_(n) { }
   virtual ~ByteArraySource();
   virtual size_t Available() const;
   virtual const char* Peek(size_t* len);
   virtual void Skip(size_t n);
  private:
   const char* ptr_;
   size_t left_;
 };
 // A Sink implementation that writes to a flat array without any bound checks.
 class UncheckedByteArraySink : public Sink {
  public:
   explicit UncheckedByteArraySink(char* dest) : dest_(dest) { }
   virtual ~UncheckedByteArraySink();
   virtual void Append(const char* data, size_t n);
   virtual char* GetAppendBuffer(size_t len, char* scratch);
   // Return the current output pointer so that a caller can see how
   // many bytes were produced.
   // Note: this is not a Sink method.
   char* CurrentDestination() const { return dest_; }
  private:
   char* dest_;
 };
 }
 #endif  // UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_

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other-licenses/snappy/src/snappy-sinksource.h