# RFC http://wiki.php.net/rfc/horizontalreuse#traits_-_reuse_of_behavior
# Ok, here we go, I guess that will result in more discussion, which is fine
# by me. But now, the patch is here, and properly archived.
#
# See below a list of notes to the patch, it also includes a list of
# points which should be fixed
#
# Internals of the Traits Patch
# -----------------------------
#
# Open TODOs
# """"""""""
#
# - Reflection API
# - support for traits for internal classes
# - currently destroy_zend_class does not handle that case
#
# Introduced Structures
# """""""""""""""""""""
#
# Data structures to encode the composition information specified in the
# source:
# - zend_trait_method_reference
# - zend_trait_precedence
# - zend_trait_alias
#
# Changes
# """""""
#
# zend_class_entry
# - uses NULL terminated lists of pointers for
# - trait_aliases
# - trait_precedences
# - do you prefer an explicit counter?
# - the information is only necessary during class composition
# but might be interesting for reflection
# - did not want to blow up class further with not really necessary length counters
#
# added keywords
# - trait
# - insteadof
#
# Added opcodes
# ZEND_ADD_TRAIT
# - similar to ZEND_ADD_INTERFACE
# - adds the trait to the list of traits of a class, no actual composition done
# ZEND_BIND_TRAITS
# - emitted in zend_do_end_class_declaration
# - concludes the class definition and will initiate the trait composition
# when the class definition is encountered during runtime
#
# Added Flags
# ZEND_ACC_TRAIT = 0x120
# ZEND_ACC_IMPLEMENT_TRAITS = 0x400000
# ZEND_FETCH_CLASS_TRAIT = 14
#
# zend_vm_execute.h
# - not sure whether the handler initialization (ZEND_ADD_TRAIT_SPEC_HANDLER,
# ZEND_BIND_TRAITS_SPEC_HANDLER) is correct, maybe it should be more selective
#
# zend_compile.c
# - refactored do_inherit_method_check
# split into do_inherit_method_check and do_inheritance_check_on_method
# - added helper functions use a '_' as prefix and are not mentioned in the
# headers
# - _copy_functions
# prepare hash-maps of functions which should be merged into a class
# here the aliases are handled
# - _merge_functions
# builds a hash-table of the methods which need to be added to a class
# does the conflict detection
# - reused php_runkit_function_copy_ctor
# - it is not identical with the original code anymore, needed to update it
# think I fixed some bugs, not sure whether all have been reported back to runkit
# - has to be renamed, left the name for the moment, to make its origin obvious
# - here might be optimization potential
# - not sure whether everything needs to be copied
# - copying the literals might be broken
# - added it since the literals array is freed by efree and gave problems
# with doubled frees
# - all immutable parts of the zend_op array should not be copied
# - am not sure which parts are immutable
# - and not sure how to avoid doubled frees on the same arrays on shutdown
# - _merge_functions_to_class
# does the final merging with the target class to handle inherited
# and overridden methods
# - small helper for NULL terminated lists
# zend_init_list, zend_add_to_list
#
# zend_language_parser.y
# - reused class definition for traits
# - there should be something with regard to properties
# - if they get explicitly defined, it might be worthwhile to
# check that there are no collisions with other traits in a composition
# (however, I would not introduce elaborate language features to control that
# but a notice for such conflicts might be nice to the developers)
#That was suggested several times already, but am still not sure whether that really reads better.
#Especially since only the trait is mentioned, since the method name would be duplicated anyway.
All packets but the row data packet are read into preallocated buffer,
either on the stack or on the heap (cmd_buffer). The size of the buffer
is always checked to skip buffer overruns. Only up to the size of the
buffer is stored into the buffer but packet->header.size has the size of
all data sent. In this case network layer bails.
This patch hardenes the reads, so if packets are malformed and shorter
than they should be there will be no further reads in the buffer.
In short, detection of malformed packets.
Felipe Pena