doxygen documentation for checkpoints.{h,cpp}

All functions in src/cryptonote_core/checkpoints.h are now documented in
doxygen style.

checkpoints.cpp has been reviewed, one function has been marked for
discussion on correctness.

src/cryptonote_core/checkpoints.cpp

@@ -84,10 +84,7 @@ namespace cryptonote
     return check_block(height, h, ignored);
   }
   //---------------------------------------------------------------------------
-  // this basically says if the blockchain is smaller than the first
-  // checkpoint then alternate blocks are allowed.  Alternatively, if the
-  // last checkpoint *before* the end of the current chain is also before
-  // the block to be added, then this is fine.
+  //FIXME: is this the desired behavior?
   bool checkpoints::is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const
   {
     if (0 == block_height)

src/cryptonote_core/checkpoints.h

@@ -36,19 +36,115 @@
 
 namespace cryptonote
 {
+  /**
+   * @brief A container for blockchain checkpoints
+   *
+   * A checkpoint is a pre-defined hash for the block at a given height.
+   * Some of these are compiled-in, while others can be loaded at runtime
+   * either from a json file or via DNS from a checkpoint-hosting server.
+   */
   class checkpoints
   {
   public:
+
+    /**
+     * @brief default constructor
+     */
     checkpoints();
+
+    /**
+     * @brief adds a checkpoint to the container
+     *
+     * @param height the height of the block the checkpoint is for
+     * @param hash_str the hash of the block, as a string
+     *
+     * @return false if parsing the hash fails, or if the height is a duplicate
+     *         AND the existing checkpoint hash does not match the new one,
+     *         otherwise returns true
+     */
     bool add_checkpoint(uint64_t height, const std::string& hash_str);
+
+    /**
+     * @brief checks if there is a checkpoint in the future
+     *
+     * This function checks if the height passed is lower than the highest
+     * checkpoint.
+     *
+     * @param height the height to check against
+     *
+     * @return false if no checkpoints, otherwise returns whether or not
+     *         the height passed is lower than the highest checkpoint.
+     */
     bool is_in_checkpoint_zone(uint64_t height) const;
-    bool check_block(uint64_t height, const crypto::hash& h) const;
+
+    /**
+     * @brief checks if the given height and hash agree with the checkpoints
+     *
+     * This function checks if the given height and hash exist in the
+     * checkpoints container.  If so, it returns whether or not the passed
+     * parameters match the stored values.
+     *
+     * @param height the height to be checked
+     * @param h the hash to be checked
+     * @param is_a_checkpoint return-by-reference if there is a checkpoint at the given height
+     *
+     * @return true if there is no checkpoint at the given height, 
+     *         true if the passed parameters match the stored checkpoint, 
+     *         false otherwise
+     */
     bool check_block(uint64_t height, const crypto::hash& h, bool& is_a_checkpoint) const;
+
+    /**
+     * @overload
+     */
+    bool check_block(uint64_t height, const crypto::hash& h) const;
+
+    /**
+     * @brief checks if alternate chain blocks should be kept for a given height
+     *
+     * this basically says if the blockchain is smaller than the first
+     * checkpoint then alternate blocks are allowed.  Alternatively, if the
+     * last checkpoint *before* the end of the current chain is also before
+     * the block to be added, then this is fine.
+     *
+     * @param blockchain_height the current blockchain height
+     * @param block_height the height of the block to be added as alternate
+     *
+     * @return true if alternate blocks are allowed given the parameters, 
+     *         otherwise false
+     */
     bool is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const;
+
+    /**
+     * @brief gets the highest checkpoint height
+     *
+     * @return the height of the highest checkpoint
+     */
     uint64_t get_max_height() const;
+
+    /**
+     * @brief gets the checkpoints container
+     *
+     * @return a const reference to the checkpoints container
+     */
     const std::map<uint64_t, crypto::hash>& get_points() const;
+
+    /**
+     * @brief checks if our checkpoints container conflicts with another
+     *
+     * A conflict refers to a case where both checkpoint sets have a checkpoint
+     * for a specific height but their hashes for that height do not match.
+     *
+     * @param other the other checkpoints instance to check against
+     *
+     * @return false if any conflict is found, otherwise true
+     */
     bool check_for_conflicts(const checkpoints& other) const;
+
+
   private:
-    std::map<uint64_t, crypto::hash> m_points;
+
+    std::map<uint64_t, crypto::hash> m_points; //!< the checkpoints container
+
   };
 }