![Anatomy of an extension
● tests -> *.phpt
○ for module test files
● config.m4/config.w32
○ for platform-specific configuration options
● ext.cpp|.c/[name].cpp|.c
○ arbitrarily named extension file
● php_ext.h/php_[name].h
○ primary extension header file](https://image.slidesharecdn.com/getting-started-with-php-extensions-201023105012/85/Getting-Started-with-PHP-Extensions-8-320.jpg)
Getting Started with PHP Extensions
- 1. Getting Started with PHP Extensions
- 2. Lochemem Bruno Michael ● PHP enthusiast from Kampala, Uganda ● Functional Programming aficionado ● Graduated college in 2019 ● Maintains PHP userland packages and extensions ● Loves ReactPHP ● Authored a book ● Loves hoops, music, movies, podcasts, and video games
- 3. So, PHP extensions? ● Written mainly in C/C++ ● Infuse the PHP userland with ad-hoc functionality ● Require interaction with a low-level PHP engine API
- 4. Why even bother? ● Extensions are typically faster than their PHP equivalents ○ Primarily because they are written in C/C++ ● Extensions allow for infusion of performant ad-hoc solutions ○ Addition of features otherwise not present in PHP userland (ext-uv, ext-apcu) ○ Either unique projects or wrappers around other C/C++ packages ● Extension-building likely results in a better understanding of PHP internals ○ Engaging endeavor likely to test your patience and skill
- 5. Pump the brakes! You have to get familiar with PHP’s lifecycle
- 6. PHP Lifecycle 1. MINIT (Module Initialization) 2. RINIT (Request Initialization) 3. RSHUTDOWN (Request Shutdown) 4. MSHUTDOWN (Module shutdown) MINIT RINIT MSHUTDOWN RSHUTDOWN
- 8. Anatomy of an extension ● tests -> *.phpt ○ for module test files ● config.m4/config.w32 ○ for platform-specific configuration options ● ext.cpp|.c/[name].cpp|.c ○ arbitrarily named extension file ● php_ext.h/php_[name].h ○ primary extension header file
- 9. php_trie ● Trie data structures for PHP ● Built in C++
- 10. So, tries huh?
- 11. What about tries? ● Potent tree structures for storing string data ● Persistent data structures ● Designed for fast traversal and string searches ● Empty root node with multiple child nodes ● Useful as dictionaries and associative maps ● Somewhat space inefficient
- 12. The first thing to do is set things up.
- 13. ● Comments ● Configuration option definitions ● Build specifics Configuring the extension (for POSIX systems)
- 14. ● Comments ● Configuration option definitions ● Build specifics Configuring the extension (for Windows systems)
- 15. Onto the primary extension header file...
- 16. Salient elements ● Extension info (name, version) ● PHP-engine header file inclusions ● Module definition ● Other discretionary constants
- 17. How about the primary extension file?
- 18. ● PHP userland-bound artifacts ● PHP lifecycle handlers php_trie.cpp’s features
- 19. ● Extension entry table ● Shared object loading routines php_trie.cpp’s features continued...
- 20. The next thing to do is implement the trie.
- 21. The scope of the implementation ● A single Trie class ● Public constructor ● Two additional methods - insert and search
- 22. ● Linked list ● Stores string keys and values ● String values are appendable to the end of each final key node C++ trie object
- 23. ● Creates a new trie entry ● Appends string to the end of a branch Insertion
- 24. ● Performs trie traversal ● Outputs a matching value at the end of a branch search/lookup
- 25. Onto the PHP engine API side of things...
- 26. What to expect ● Macros, macros, and more macros ● Engine-specific functions ● Memory management ● PHP internals conventions
- 27. ● Basis for the PHP userland object ● Contains C++ trie object PHP-C/C++ trie object
- 28. More PHP object-related stuff ● Object handlers ● Class registration ● The MINIT function
- 29. Things to be mindful of when writing functions ● PHP zvals ● Argument parsing ● Return values ● Memory management
- 30. ● Zend value container ● PHP variables ● C union ● Has unique macros for multiple use-cases (ZVAL_P, Z_TYPE_P, Z_LVAL_P, etc...) zvals
- 31. ● All manner of types (string, float, array, etc...) ● Arguments should be relevant to function Argument parsing
- 32. ● PHP engine API return_value variable ● PHP engine API return macros ● Should translate to PHP userland types Return values
- 33. ● Allocate something then free it ● Use PHP engine API helpers ● Guards against some nasty leaks and faults Memory management
- 34. ● Create a trie ● Initializes the Trie object __construct
- 35. ● Takes two arguments ● boolean to zend_bool return value conversion insert
- 36. ● Takes one argument ● C++ string to C string conversion search
- 38. The .phpt file ● De-facto engine test file format ● Sections vs succinct PHP method assertions (SKIPIF, EXPECT, FILE, etc...) ● Trigger tests by using the directive make test
- 39. All that’s left is to build and use the extension.
- 40. ● Requires autoconf, make, gcc, and libtool ● Installs the extension in the PHP modules directory
- 41. Moving Forward... ● Take a look at the Internals book ● Contact someone knowledgeable ● Look at engine code ● Sharpen your C/C++ skills
- 42. Thanks.