1How to use this library 2----------------------- 3There are three options to use this library: 4 5## Option 1) Fully in-process 6In this mode Producer, Consumers and the Service are hosted in the same process. 7This is not too interesting other than tests and particular cases of nesting 8tracing instances coming from different libraries within the same process 9(concrete example v8, skia and webrtc in Chrome). 10In this configuration, the client is expected to at least: 11- Create a TracingService instance via TracingService::CreateInstance 12 (see `core/tracing_service.h`) 13- Subclass Producer (`core/producer.h`) and connect it to the service. 14- Provide a TaskRunner implementation (see `test/test_task_runner.h`) 15- Provide a trivial SharedMemory implementation (`core/shared_memory.h`) which 16 is simply backed by a malloc() buffer. 17 18## Option 2) Using the provided UNIX RPC transport 19The `include/unix_rpc` provides the building blocks necessary to implement a RPC 20mechanism that allows Producer(s), Consumer(s) and Service to be hosted on 21different processes on the same machine and talk over a UNIX domain socket. 22- Producer(s) are expected to get a service proxy via 23`UnixServiceConnection::ConnectAsProducer()`. 24- The `Service` must be instantiated via `UnixServiceHost::CreateInstance()`. The 25returned instance encapsulates the `Service` and exposes two UNIX sockets (one 26for Producer(s), one for Consumer(s)) on the current process. 27 28## Option 3) Providing a custom RPC transport 29Similar to Option 2, but the client creates its own transport mechanism, 30defining how methods are proxies between instances and providing a SharedMemory 31implementation that can be transferred through RPC. Concrete example of this is 32Chrome implementing this library over a Mojo transport. 33 34 35Directory layout 36---------------- 37 38`include/` 39Is the public API that clients of this library are allowed to depend on. 40Headers inside include/ cannot depend on anything else. 41 42`src/` 43Is the actual implementation that clients can link but not expected to access 44at a source-code level. 45 46 47**Both have the following sub-structure**: 48 49`{include,src}/core/` 50"Core" is the pure c++11 tracing machinery that deals with bookkeeping, 51ring-buffering, partitioning and multiplexing but knows nothing about 52platform-specific things like implementation of shared memory and RPC mechanism. 53 54`{include,src}/unix_rpc/` 55A concrete implementation of the transport layer based on UNIX domain sockets 56and posix shared memory. 57