polybar-dwm/src/ipc/decoder.cpp
2022-02-20 21:40:48 +01:00

136 lines
3.6 KiB
C++

#include "ipc/decoder.hpp"
#include <cassert>
#include <cstring>
POLYBAR_NS
namespace ipc {
decoder::decoder(const logger& logger, cb callback) : callback(callback), m_log(logger) {}
void decoder::on_read(const uint8_t* data, size_t size) {
if (state == state::CLOSED) {
throw error("Decoder is closed");
}
try {
process_data(data, size);
} catch (const error& e) {
close();
throw;
}
}
void decoder::process_data(const uint8_t* data, size_t size) {
m_log.trace("ipc: Received %zd bytes", size);
size_t buf_pos = 0;
size_t remain = size;
while (remain > 0) {
if (state == state::HEADER) {
ssize_t num_read = process_header_data(data + buf_pos, remain);
assert(num_read > 0);
assert(remain >= (size_t)num_read);
buf_pos += num_read;
remain -= num_read;
/*
* If an empty message arrives, we need to explicitly trigger this because there is no further data that would
* call process_msg_data.
*/
if (remain == 0 && state == state::PAYLOAD && to_read_buf == 0) {
ssize_t num_read_data = process_msg_data(data + buf_pos, remain);
assert(num_read_data == 0);
(void)num_read_data;
}
} else {
assert(to_read_header == 0);
ssize_t num_read = process_msg_data(data + buf_pos, remain);
assert(num_read > 0);
assert(remain >= (size_t)num_read);
buf_pos += num_read;
remain -= num_read;
}
}
}
void decoder::close() noexcept {
state = state::CLOSED;
}
bool decoder::closed() const {
return state == state::CLOSED;
}
/**
* If we are waiting for header data, read as many bytes as possible from the given buffer.
*
* @return Number of bytes processed.
* @throws decoder::error on message errors
*/
ssize_t decoder::process_header_data(const uint8_t* data, size_t size) {
assert(state == state::HEADER);
assert(to_read_header > 0);
size_t num_read = std::min(size, to_read_header);
std::copy(data, data + num_read, header.d + HEADER_SIZE - to_read_header);
to_read_header -= num_read;
if (to_read_header == 0) {
uint8_t version = header.s.version;
uint32_t msg_size = header.s.size;
m_log.trace(
"Received full ipc header (magic=%.*s version=%d size=%zd)", MAGIC.size(), header.s.magic, version, msg_size);
if (memcmp(header.s.magic, MAGIC.data(), MAGIC.size()) != 0) {
throw error("Invalid magic header, expected '" + MAGIC_STR + "', got '" +
string(reinterpret_cast<const char*>(header.s.magic), MAGIC.size()) + "'");
}
if (version != VERSION) {
throw error("Unsupported message format version " + to_string(version));
}
assert(buf.empty());
state = state::PAYLOAD;
to_read_buf = msg_size;
}
return num_read;
}
/**
* If we are waiting for message data, read as many bytes as possible from the given buffer.
*
* @return Number of bytes processed.
* @throws decoder::error on message errors
*/
ssize_t decoder::process_msg_data(const uint8_t* data, size_t size) {
assert(state == state::PAYLOAD);
size_t num_read = std::min(size, to_read_buf);
buf.reserve(buf.size() + num_read);
for (size_t i = 0; i < num_read; i++) {
buf.push_back(data[i]);
}
to_read_buf -= num_read;
if (to_read_buf == 0) {
callback(header.s.version, header.s.type, buf);
state = state::HEADER;
to_read_header = HEADER_SIZE;
buf.clear();
}
return num_read;
}
} // namespace ipc
POLYBAR_NS_END