Transport's error_handle is used to capture different types of errors
including esp_err_t from esp-tls and socket/system errors.
This change adds the following error codes for TCP transport:
* connection closed by a FIN flag (clean closure from server)
* DNS resolution problem
* connection timeout
These errors are already defined in esp-tls component and since this
component will be used in the future for both TCP and SSL transport, we
currently report these issues in transport::error_handle::esp_tls_last_error
of standard esp error type (esp_err_t)
Closes https://github.com/espressif/esp-mqtt/issues/182
Internal tcp_transport functions could now use custom socket operations.
This is used for WebSocket transport, when we typically wait for clean
connection closure, i.e. selecting for read/error with expected errno or
recv size=0 while socket readable (=connection terminated by FIN flag)
1. separate rom include files and linkscript to esp_rom
2. modefiy "include rom/xxx.h" to "include esp32/rom/xxx.h"
3. Forward compatible
4. update mqtt
tcp_transport component used public header files such as 'transport.h', etc. which are too generic and might collide with user or user libraries headers
This change closes#2417
Four internal APIs `esp_http_client_connect()`, `http_client_prepare_first_line()`, `esp_http_client_request_send()` and
`esp_http_client_send_post_data()` API have been added for perfoming connection establishment (sync as well as async),
preparing first line, sending request and sending post data respectively.
In `transport_ssl`, `ssl_connect_async()` API has been added for establishing asynchronous connection.
added docs and tests for mqtt library, small fixes (removed warnings, option for custom outbox, websocket bug fixed for longer transports). refactored to use common tcp_transport component, support for CMake build system.
Closes#2108
David Cermak