327 lines · cpp
1//===-- LineEditor.cpp - line editor --------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "llvm/LineEditor/LineEditor.h"10#include "llvm/ADT/STLExtras.h"11#include "llvm/ADT/SmallString.h"12#include "llvm/Config/config.h"13#include "llvm/Support/Path.h"14#include "llvm/Support/raw_ostream.h"15#include <algorithm>16#include <cassert>17#include <cstdio>18#ifdef HAVE_LIBEDIT19#include <histedit.h>20constexpr int DefaultHistorySize = 800;21#endif22 23using namespace llvm;24 25std::string LineEditor::getDefaultHistoryPath(StringRef ProgName) {26 SmallString<32> Path;27 if (sys::path::home_directory(Path)) {28 sys::path::append(Path, "." + ProgName + "-history");29 return std::string(Path);30 }31 return std::string();32}33 34LineEditor::CompleterConcept::~CompleterConcept() = default;35LineEditor::ListCompleterConcept::~ListCompleterConcept() = default;36 37std::string LineEditor::ListCompleterConcept::getCommonPrefix(38 const std::vector<Completion> &Comps) {39 assert(!Comps.empty());40 41 std::string CommonPrefix = Comps[0].TypedText;42 for (const Completion &C : llvm::drop_begin(Comps)) {43 size_t Len = std::min(CommonPrefix.size(), C.TypedText.size());44 size_t CommonLen = 0;45 for (; CommonLen != Len; ++CommonLen) {46 if (CommonPrefix[CommonLen] != C.TypedText[CommonLen])47 break;48 }49 CommonPrefix.resize(CommonLen);50 }51 return CommonPrefix;52}53 54LineEditor::CompletionAction55LineEditor::ListCompleterConcept::complete(StringRef Buffer, size_t Pos) const {56 CompletionAction Action;57 std::vector<Completion> Comps = getCompletions(Buffer, Pos);58 if (Comps.empty()) {59 Action.Kind = CompletionAction::AK_ShowCompletions;60 return Action;61 }62 63 std::string CommonPrefix = getCommonPrefix(Comps);64 65 // If the common prefix is non-empty we can simply insert it. If there is a66 // single completion, this will insert the full completion. If there is more67 // than one, this might be enough information to jog the user's memory but if68 // not the user can also hit tab again to see the completions because the69 // common prefix will then be empty.70 if (CommonPrefix.empty()) {71 Action.Kind = CompletionAction::AK_ShowCompletions;72 for (const Completion &Comp : Comps)73 Action.Completions.push_back(Comp.DisplayText);74 } else {75 Action.Kind = CompletionAction::AK_Insert;76 Action.Text = CommonPrefix;77 }78 79 return Action;80}81 82LineEditor::CompletionAction LineEditor::getCompletionAction(StringRef Buffer,83 size_t Pos) const {84 if (!Completer) {85 CompletionAction Action;86 Action.Kind = CompletionAction::AK_ShowCompletions;87 return Action;88 }89 90 return Completer->complete(Buffer, Pos);91}92 93#ifdef HAVE_LIBEDIT94 95// libedit-based implementation.96 97struct LineEditor::InternalData {98 LineEditor *LE;99 100 History *Hist;101 EditLine *EL;102 103 unsigned PrevCount;104 std::string ContinuationOutput;105 106 FILE *Out;107};108 109namespace {110 111const char *ElGetPromptFn(EditLine *EL) {112 LineEditor::InternalData *Data;113 if (el_get(EL, EL_CLIENTDATA, &Data) == 0)114 return Data->LE->getPrompt().c_str();115 return "> ";116}117 118// Handles tab completion.119//120// This function is really horrible. But since the alternative is to get into121// the line editor business, here we are.122unsigned char ElCompletionFn(EditLine *EL, int ch) {123 LineEditor::InternalData *Data;124 if (el_get(EL, EL_CLIENTDATA, &Data) == 0) {125 if (!Data->ContinuationOutput.empty()) {126 // This is the continuation of the AK_ShowCompletions branch below.127 FILE *Out = Data->Out;128 129 // Print the required output (see below).130 ::fwrite(Data->ContinuationOutput.c_str(),131 Data->ContinuationOutput.size(), 1, Out);132 133 // Push a sequence of Ctrl-B characters to move the cursor back to its134 // original position.135 std::string Prevs(Data->PrevCount, '\02');136 ::el_push(EL, const_cast<char *>(Prevs.c_str()));137 138 Data->ContinuationOutput.clear();139 140 return CC_REFRESH;141 }142 143 const LineInfo *LI = ::el_line(EL);144 LineEditor::CompletionAction Action = Data->LE->getCompletionAction(145 StringRef(LI->buffer, LI->lastchar - LI->buffer),146 LI->cursor - LI->buffer);147 switch (Action.Kind) {148 case LineEditor::CompletionAction::AK_Insert:149 ::el_insertstr(EL, Action.Text.c_str());150 return CC_REFRESH;151 152 case LineEditor::CompletionAction::AK_ShowCompletions:153 if (Action.Completions.empty()) {154 return CC_REFRESH_BEEP;155 } else {156 // Push a Ctrl-E and a tab. The Ctrl-E causes libedit to move the cursor157 // to the end of the line, so that when we emit a newline we will be on158 // a new blank line. The tab causes libedit to call this function again159 // after moving the cursor. There doesn't seem to be anything we can do160 // from here to cause libedit to move the cursor immediately. This will161 // break horribly if the user has rebound their keys, so for now we do162 // not permit user rebinding.163 ::el_push(EL, const_cast<char *>("\05\t"));164 165 // This assembles the output for the continuation block above.166 raw_string_ostream OS(Data->ContinuationOutput);167 168 // Move cursor to a blank line.169 OS << "\n";170 171 // Emit the completions.172 for (const std::string &Completion : Action.Completions)173 OS << Completion << "\n";174 175 // Fool libedit into thinking nothing has changed. Reprint its prompt176 // and the user input. Note that the cursor will remain at the end of177 // the line after this.178 OS << Data->LE->getPrompt()179 << StringRef(LI->buffer, LI->lastchar - LI->buffer);180 181 // This is the number of characters we need to tell libedit to go back:182 // the distance between end of line and the original cursor position.183 Data->PrevCount = LI->lastchar - LI->cursor;184 185 return CC_REFRESH;186 }187 }188 }189 return CC_ERROR;190}191 192} // end anonymous namespace193 194LineEditor::LineEditor(StringRef ProgName, StringRef HistoryPath, FILE *In,195 FILE *Out, FILE *Err)196 : Prompt((ProgName + "> ").str()), HistoryPath(std::string(HistoryPath)),197 Data(new InternalData) {198 if (HistoryPath.empty())199 this->HistoryPath = getDefaultHistoryPath(ProgName);200 201 Data->LE = this;202 Data->Out = Out;203 204 Data->Hist = ::history_init();205 assert(Data->Hist);206 207 Data->EL = ::el_init(ProgName.str().c_str(), In, Out, Err);208 assert(Data->EL);209 210 ::el_set(Data->EL, EL_PROMPT, ElGetPromptFn);211 ::el_set(Data->EL, EL_EDITOR, "emacs");212 ::el_set(Data->EL, EL_HIST, history, Data->Hist);213 ::el_set(Data->EL, EL_ADDFN, "tab_complete", "Tab completion function",214 ElCompletionFn);215 ::el_set(Data->EL, EL_BIND, "\t", "tab_complete", NULL);216 ::el_set(Data->EL, EL_BIND, "^r", "em-inc-search-prev",217 NULL); // Cycle through backwards search, entering string218 ::el_set(Data->EL, EL_BIND, "^w", "ed-delete-prev-word",219 NULL); // Delete previous word, behave like bash does.220 ::el_set(Data->EL, EL_BIND, "\033[3~", "ed-delete-next-char",221 NULL); // Fix the delete key.222 ::el_set(Data->EL, EL_CLIENTDATA, Data.get());223 224 setHistorySize(DefaultHistorySize);225 HistEvent HE;226 ::history(Data->Hist, &HE, H_SETUNIQUE, 1);227 loadHistory();228}229 230LineEditor::~LineEditor() {231 saveHistory();232 233 ::history_end(Data->Hist);234 ::el_end(Data->EL);235 ::fwrite("\n", 1, 1, Data->Out);236}237 238void LineEditor::saveHistory() {239 if (!HistoryPath.empty()) {240 HistEvent HE;241 ::history(Data->Hist, &HE, H_SAVE, HistoryPath.c_str());242 }243}244 245void LineEditor::loadHistory() {246 if (!HistoryPath.empty()) {247 HistEvent HE;248 ::history(Data->Hist, &HE, H_LOAD, HistoryPath.c_str());249 }250}251 252void LineEditor::setHistorySize(int size) {253 HistEvent HE;254 ::history(Data->Hist, &HE, H_SETSIZE, size);255}256 257std::optional<std::string> LineEditor::readLine() const {258 // Call el_gets to prompt the user and read the user's input.259 int LineLen = 0;260 const char *Line = ::el_gets(Data->EL, &LineLen);261 262 // Either of these may mean end-of-file.263 if (!Line || LineLen == 0)264 return std::nullopt;265 266 // Strip any newlines off the end of the string.267 while (LineLen > 0 &&268 (Line[LineLen - 1] == '\n' || Line[LineLen - 1] == '\r'))269 --LineLen;270 271 HistEvent HE;272 if (LineLen > 0)273 ::history(Data->Hist, &HE, H_ENTER, Line);274 275 return std::string(Line, LineLen);276}277 278#else // HAVE_LIBEDIT279 280// Simple fgets-based implementation.281 282struct LineEditor::InternalData {283 FILE *In;284 FILE *Out;285};286 287LineEditor::LineEditor(StringRef ProgName, StringRef HistoryPath, FILE *In,288 FILE *Out, FILE *Err)289 : Prompt((ProgName + "> ").str()), Data(new InternalData) {290 Data->In = In;291 Data->Out = Out;292}293 294LineEditor::~LineEditor() {295 ::fwrite("\n", 1, 1, Data->Out);296}297 298void LineEditor::saveHistory() {}299void LineEditor::loadHistory() {}300void LineEditor::setHistorySize(int size) {}301 302std::optional<std::string> LineEditor::readLine() const {303 ::fprintf(Data->Out, "%s", Prompt.c_str());304 305 std::string Line;306 do {307 char Buf[64];308 char *Res = ::fgets(Buf, sizeof(Buf), Data->In);309 if (!Res) {310 if (Line.empty())311 return std::nullopt;312 else313 return Line;314 }315 Line.append(Buf);316 } while (Line.empty() ||317 (Line[Line.size() - 1] != '\n' && Line[Line.size() - 1] != '\r'));318 319 while (!Line.empty() &&320 (Line[Line.size() - 1] == '\n' || Line[Line.size() - 1] == '\r'))321 Line.resize(Line.size() - 1);322 323 return Line;324}325 326#endif // HAVE_LIBEDIT327