ClickHouse/base/common/ReadlineLineReader.cpp

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2020-02-25 08:30:11 +00:00
#include <common/ReadlineLineReader.h>
#include <ext/scope_guard.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
namespace
{
/// Trim ending whitespace inplace
void trim(String & s)
{
s.erase(std::find_if(s.rbegin(), s.rend(), [](int ch) { return !std::isspace(ch); }).base(), s.end());
}
}
static const LineReader::Suggest * suggest;
/// Points to current word to suggest.
static LineReader::Suggest::Words::const_iterator pos;
/// Points after the last possible match.
static LineReader::Suggest::Words::const_iterator end;
/// Set iterators to the matched range of words if any.
static void findRange(const char * prefix, size_t prefix_length)
{
std::string prefix_str(prefix);
std::tie(pos, end) = suggest->getCompletions(prefix_str, prefix_length);
}
/// Iterates through matched range.
static char * nextMatch()
{
if (pos >= end)
return nullptr;
/// readline will free memory by itself.
char * word = strdup(pos->c_str());
++pos;
return word;
}
static char * generate(const char * text, int state)
{
if (!suggest->ready)
return nullptr;
if (state == 0)
findRange(text, strlen(text));
/// Do not append whitespace after word. For unknown reason, rl_completion_append_character = '\0' does not work.
rl_completion_suppress_append = 1;
return nextMatch();
};
ReadlineLineReader::ReadlineLineReader(const Suggest & suggest_, const String & history_file_path_, char extender_, char delimiter_)
: LineReader(history_file_path_, extender_, delimiter_)
{
suggest = &suggest_;
if (!history_file_path.empty())
{
int res = read_history(history_file_path.c_str());
if (res)
std::cerr << "Cannot read history from file " + history_file_path + ": "+ strerror(errno) << std::endl;
}
/// Added '.' to the default list. Because it is used to separate database and table.
rl_basic_word_break_characters = word_break_characters;
/// Not append whitespace after single suggestion. Because whitespace after function name is meaningless.
rl_completion_append_character = '\0';
rl_completion_entry_function = generate;
/// Install Ctrl+C signal handler that will be used in interactive mode.
if (rl_initialize())
throw std::runtime_error("Cannot initialize readline");
auto clear_prompt_or_exit = [](int)
{
/// This is signal safe.
ssize_t res = write(STDOUT_FILENO, "\n", 1);
/// Allow to quit client while query is in progress by pressing Ctrl+C twice.
/// (First press to Ctrl+C will try to cancel query by InterruptListener).
if (res == 1 && rl_line_buffer[0] && !RL_ISSTATE(RL_STATE_DONE))
{
rl_replace_line("", 0);
if (rl_forced_update_display())
_exit(0);
}
else
{
/// A little dirty, but we struggle to find better way to correctly
/// force readline to exit after returning from the signal handler.
_exit(0);
}
};
if (signal(SIGINT, clear_prompt_or_exit) == SIG_ERR)
throw std::runtime_error(std::string("Cannot set signal handler for readline: ") + strerror(errno));
}
ReadlineLineReader::~ReadlineLineReader()
{
}
LineReader::InputStatus ReadlineLineReader::readOneLine(const String & prompt)
{
input.clear();
const char* cinput = readline(prompt.c_str());
if (cinput == nullptr)
return (errno != EAGAIN) ? ABORT : RESET_LINE;
input = cinput;
trim(input);
return INPUT_LINE;
}
void ReadlineLineReader::addToHistory(const String & line)
{
add_history(line.c_str());
}
#if RL_VERSION_MAJOR >= 7
#define BRACK_PASTE_PREF "\033[200~"
#define BRACK_PASTE_SUFF "\033[201~"
#define BRACK_PASTE_LAST '~'
#define BRACK_PASTE_SLEN 6
/// This handler bypasses some unused macro/event checkings and remove trailing newlines before insertion.
static int clickhouse_rl_bracketed_paste_begin(int /* count */, int /* key */)
{
std::string buf;
buf.reserve(128);
RL_SETSTATE(RL_STATE_MOREINPUT);
SCOPE_EXIT(RL_UNSETSTATE(RL_STATE_MOREINPUT));
int c;
while ((c = rl_read_key()) >= 0)
{
if (c == '\r')
c = '\n';
buf.push_back(c);
if (buf.size() >= BRACK_PASTE_SLEN && c == BRACK_PASTE_LAST && buf.substr(buf.size() - BRACK_PASTE_SLEN) == BRACK_PASTE_SUFF)
{
buf.resize(buf.size() - BRACK_PASTE_SLEN);
break;
}
}
trim(buf);
return static_cast<size_t>(rl_insert_text(buf.c_str())) == buf.size() ? 0 : 1;
}
#endif
void ReadlineLineReader::enableBracketedPaste()
{
#if RL_VERSION_MAJOR >= 7
rl_variable_bind("enable-bracketed-paste", "on");
/// Use our bracketed paste handler to get better user experience. See comments above.
rl_bind_keyseq(BRACK_PASTE_PREF, clickhouse_rl_bracketed_paste_begin);
#endif
};