This directory contains the infrastructure blocks needed to support QUIC in certain platform. These APIs act as interaction layers between QUIC core and either the upper layer application (i.e. Chrome, Envoy) or the platform‘s own infrastructure (i.e. logging, test framework and system IO). QUIC core needs the implementations of these APIs to build and function appropriately. There is unidirectional dependency from QUIC core to most of the APIs here, such as QUIC_LOG and QuicMutex, but a few APIs also depend back on QUIC core’s basic QUIC data types, such as QuicClock and QuicSleep.
APIs used by QUIC core:
Most APIs are used by QUIC core to interact with platform infrastructure (i.e. QUIC_LOG) or to wrap around platform dependent data types (i.e. QuicThread), the dependency is:
application -> quic_core -> quic_platform_api
| |
v v
platform_infrastructure <- quic_platform_impl
APIs used by applications:
Some APIs are used by applications to interact with QUIC core (i.e. QuicMemSlice). For such APIs, their dependency model is:
application -> quic_core -> quic_platform_api
| ^
| |
-------------------> quic_platform_impl
| |
| v
-------------------> platform_infrastructure
An example for such dependency is QuicClock.
Or
application -> quic_core -> quic_platform_api
| ^
| |
| v
-------------------> quic_platform_impl
| |
| v
-------------------> platform_infrastructure
An example for such dependency is QuicMemSlice.
QuicMemSlice : QuicMemSlice is used to wrap application data and pass to QUIC stream‘s write interface. It refers to a memory block of data which should be around till QuicMemSlice::Reset() is called. It’s upto each platform, to implement it as reference counted or not.
QuicClock : QuicClock is used by QUIC core to get current time. Its instance is created by applications and passed into QuicDispatcher and QuicConnectionHelperInterface.
TODO(b/131224336) add document for other APIs