lix/tests/functional/repl_characterization/test-session.hh

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#pragma once
///@file
#include <functional>
#include <sched.h>
#include <span>
#include <string>
#include "file-descriptor.hh"
#include "tests/terminal-code-eater.hh"
namespace nix {
struct RunningProcess
{
pid_t pid;
Pipe procStdin;
Pipe procStdout;
static RunningProcess start(std::string executable, Strings args);
};
/** DFA that catches repl prompts */
class ReplOutputParser
{
public:
ReplOutputParser(std::string prompt) : prompt(prompt)
{
assert(!prompt.empty());
}
/** Feeds in a character and returns whether this is an open prompt */
bool feed(char c);
enum class State {
Prompt,
Context,
};
private:
State state = State::Prompt;
size_t pos_in_prompt = 0;
std::string const prompt;
void transition(State state, char responsible_char, bool wasPrompt = false);
};
struct TestSession
{
RunningProcess proc;
ReplOutputParser outputParser;
TerminalCodeEater eater;
std::string outLog;
std::string prompt;
TestSession(std::string prompt, RunningProcess && proc)
: proc(std::move(proc))
, outputParser(prompt)
, eater{}
, outLog{}
, prompt(prompt)
{
}
/** Waits for the prompt and then returns if a prompt was found */
bool waitForPrompt();
/** Feeds a line of input into the command */
void runCommand(std::string command);
/** Closes the session, closing standard input and waiting for standard
* output to close, capturing any remaining output. */
void close();
private:
/** Waits until the command closes its output */
void wait();
enum class ReadOutThenCallbackResult { Stop, Continue };
using ReadOutThenCallback = std::function<ReadOutThenCallbackResult(std::span<const char>)>;
/** Reads some chunks of output, calling the callback provided for each
* chunk and stopping if it returns Stop.
*
* @returns false if EOF, true if the callback requested we stop first.
* */
bool readOutThen(ReadOutThenCallback cb);
};
};