maurice/snix
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Replace readline by linenoise

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Using linenoise avoids a license compatibility issue (#1356), is a lot
smaller and doesn't pull in ncurses.
This commit is contained in:
Eelco Dolstra 2017-05-10 18:34:18 +02:00
parent 82a9c93c7f
commit c5f23f10a8
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GPG key ID: 8170B4726D7198DE
10 changed files with 1379 additions and 134 deletions
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171
src/nix/repl.cc
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@ -1,13 +1,8 @@
#if HAVE_LIBREADLINE
#include <iostream>
#include <cstdlib>
#include <setjmp.h>
#include <readline/readline.h>
#include <readline/history.h>
#include "shared.hh"
#include "eval.hh"
#include "eval-inline.hh"
@ -18,6 +13,9 @@
#include "affinity.hh"
#include "globals.hh"
#include "command.hh"
#include "finally.hh"
#include "src/linenoise/linenoise.h"
namespace nix {
@ -44,14 +42,11 @@ struct NixRepl
const Path historyFile;
StringSet completions;
StringSet::iterator curCompletion;
NixRepl(const Strings & searchPath, nix::ref<Store> store);
~NixRepl();
void mainLoop(const Strings & files);
void completePrefix(string prefix);
bool getLine(string & input, const char * prompt);
StringSet completePrefix(string prefix);
bool getLine(string & input, const std::string &prompt);
Path getDerivationPath(Value & v);
bool processLine(string line);
void loadFile(const Path & path);
@ -122,7 +117,17 @@ NixRepl::NixRepl(const Strings & searchPath, nix::ref<Store> store)
NixRepl::~NixRepl()
{
write_history(historyFile.c_str());
linenoiseHistorySave(historyFile.c_str());
}
static NixRepl * curRepl; // ugly
static void completionCallback(const char * s, linenoiseCompletions *lc)
{
/* Otherwise, return all symbols that start with the prefix. */
for (auto & c : curRepl->completePrefix(s))
linenoiseAddCompletion(lc, c.c_str());
}
@ -137,22 +142,20 @@ void NixRepl::mainLoop(const Strings & files)
reloadFiles();
if (!loadedFiles.empty()) std::cout << std::endl;
// Allow nix-repl specific settings in .inputrc
rl_readline_name = "nix-repl";
using_history();
createDirs(dirOf(historyFile));
read_history(historyFile.c_str());
linenoiseHistorySetMaxLen(1000);
linenoiseHistoryLoad(historyFile.c_str());
string input;
curRepl = this;
linenoiseSetCompletionCallback(completionCallback);
std::string input;
while (true) {
// When continuing input from previous lines, don't print a prompt, just align to the same
// number of chars as the prompt.
const char * prompt = input.empty() ? "nix-repl> " : " ";
if (!getLine(input, prompt)) {
std::cout << std::endl;
if (!getLine(input, input.empty() ? "nix-repl> " : " "))
break;
}
try {
if (!removeWhitespace(input).empty() && !processLine(input)) return;
@ -170,103 +173,57 @@ void NixRepl::mainLoop(const Strings & files)
printMsg(lvlError, format(error + "%1%%2%") % (settings.showTrace ? e.prefix() : "") % e.msg());
}
// We handled the current input fully, so we should clear it and read brand new input.
// We handled the current input fully, so we should clear it
// and read brand new input.
linenoiseHistoryAdd(input.c_str());
input.clear();
std::cout << std::endl;
}
}
/* Apparently, the only way to get readline() to return on Ctrl-C
(SIGINT) is to use siglongjmp(). That's fucked up... */
static sigjmp_buf sigintJmpBuf;
static void sigintHandler(int signo)
bool NixRepl::getLine(string & input, const std::string &prompt)
{
siglongjmp(sigintJmpBuf, 1);
}
/* Oh, if only g++ had nested functions... */
NixRepl * curRepl;
char * completerThunk(const char * s, int state)
{
string prefix(s);
/* If the prefix has a slash in it, use readline's builtin filename
completer. */
if (prefix.find('/') != string::npos)
return rl_filename_completion_function(s, state);
/* Otherwise, return all symbols that start with the prefix. */
if (state == 0) {
curRepl->completePrefix(s);
curRepl->curCompletion = curRepl->completions.begin();
}
if (curRepl->curCompletion == curRepl->completions.end()) return 0;
return strdup((curRepl->curCompletion++)->c_str());
}
bool NixRepl::getLine(string & input, const char * prompt)
{
struct sigaction act, old;
act.sa_handler = sigintHandler;
sigfillset(&act.sa_mask);
act.sa_flags = 0;
if (sigaction(SIGINT, &act, &old))
throw SysError("installing handler for SIGINT");
static sigset_t savedSignalMask, set;
sigemptyset(&set);
sigaddset(&set, SIGINT);
if (sigprocmask(SIG_UNBLOCK, &set, &savedSignalMask))
throw SysError("unblocking SIGINT");
if (sigsetjmp(sigintJmpBuf, 1)) {
input.clear();
} else {
curRepl = this;
rl_completion_entry_function = completerThunk;
char * s = readline(prompt);
if (!s) return false;
input.append(s);
input.push_back('\n');
if (!removeWhitespace(s).empty()) {
add_history(s);
append_history(1, 0);
}
free(s);
}
_isInterrupted = 0;
if (sigprocmask(SIG_SETMASK, &savedSignalMask, nullptr))
throw SysError("restoring signals");
if (sigaction(SIGINT, &old, 0))
throw SysError("restoring handler for SIGINT");
char * s = linenoise(prompt.c_str());
Finally doFree([&]() { linenoiseFree(s); });
if (!s) return false;
input += s;
return true;
}
void NixRepl::completePrefix(string prefix)
StringSet NixRepl::completePrefix(string prefix)
{
completions.clear();
StringSet completions;
size_t dot = prefix.rfind('.');
size_t start = prefix.find_last_of(" \n\r\t(){}[]");
std::string prev, cur;
if (start == std::string::npos) {
prev = "";
cur = prefix;
} else {
prev = std::string(prefix, 0, start + 1);
cur = std::string(prefix, start + 1);
}
if (dot == string::npos) {
size_t slash, dot;
if ((slash = cur.rfind('/')) != string::npos) {
try {
auto dir = std::string(cur, 0, slash);
auto prefix2 = std::string(cur, slash + 1);
for (auto & entry : readDirectory(dir == "" ? "/" : dir)) {
if (entry.name[0] != '.' && hasPrefix(entry.name, prefix2))
completions.insert(prev + dir + "/" + entry.name);
}
} catch (Error &) {
}
} else if ((dot = cur.rfind('.')) == string::npos) {
/* This is a variable name; look it up in the current scope. */
StringSet::iterator i = varNames.lower_bound(prefix);
StringSet::iterator i = varNames.lower_bound(cur);
while (i != varNames.end()) {
if (string(*i, 0, prefix.size()) != prefix) break;
completions.insert(*i);
if (string(*i, 0, cur.size()) != cur) break;
completions.insert(prev + *i);
i++;
}
} else {
@ -274,8 +231,8 @@ void NixRepl::completePrefix(string prefix)
/* This is an expression that should evaluate to an
attribute set. Evaluate it to get the names of the
attributes. */
string expr(prefix, 0, dot);
string prefix2 = string(prefix, dot + 1);
string expr(cur, 0, dot);
string cur2 = string(cur, dot + 1);
Expr * e = parseString(expr);
Value v;
@ -284,8 +241,8 @@ void NixRepl::completePrefix(string prefix)
for (auto & i : *v.attrs) {
string name = i.name;
if (string(name, 0, prefix2.size()) != prefix2) continue;
completions.insert(expr + "." + name);
if (string(name, 0, cur2.size()) != cur2) continue;
completions.insert(prev + expr + "." + name);
}
} catch (ParseError & e) {
@ -296,6 +253,8 @@ void NixRepl::completePrefix(string prefix)
// Quietly ignore undefined variable errors.
}
}
return completions;
}
@ -728,5 +687,3 @@ struct CmdRepl : StoreCommand
static RegisterCommand r1(make_ref<CmdRepl>());
}
#endif