1 //===-- llvm/LineEditor/LineEditor.h - line editor --------------*- C++ -*-===// 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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_LINEEDITOR_LINEEDITOR_H 10 #define LLVM_LINEEDITOR_LINEEDITOR_H 11 12 #include "llvm/ADT/StringRef.h" 13 #include <cstdio> 14 #include <memory> 15 #include <optional> 16 #include <string> 17 #include <utility> 18 #include <vector> 19 20 namespace llvm { 21 22 class LineEditor { 23 public: 24 /// Create a LineEditor object. 25 /// 26 /// \param ProgName The name of the current program. Used to form a default 27 /// prompt. 28 /// \param HistoryPath Path to the file in which to store history data, if 29 /// possible. 30 /// \param In The input stream used by the editor. 31 /// \param Out The output stream used by the editor. 32 /// \param Err The error stream used by the editor. 33 LineEditor(StringRef ProgName, StringRef HistoryPath = "", FILE *In = stdin, 34 FILE *Out = stdout, FILE *Err = stderr); 35 ~LineEditor(); 36 37 /// Reads a line. 38 /// 39 /// \return The line, or std::optional<std::string>() on EOF. 40 std::optional<std::string> readLine() const; 41 42 void saveHistory(); 43 void loadHistory(); 44 void setHistorySize(int size); 45 46 static std::string getDefaultHistoryPath(StringRef ProgName); 47 48 /// The action to perform upon a completion request. 49 struct CompletionAction { 50 enum ActionKind { 51 /// Insert Text at the cursor position. 52 AK_Insert, 53 /// Show Completions, or beep if the list is empty. 54 AK_ShowCompletions 55 }; 56 57 ActionKind Kind; 58 59 /// The text to insert. 60 std::string Text; 61 62 /// The list of completions to show. 63 std::vector<std::string> Completions; 64 }; 65 66 /// A possible completion at a given cursor position. 67 struct Completion { 68 Completion() = default; 69 Completion(const std::string &TypedText, const std::string &DisplayText) 70 : TypedText(TypedText), DisplayText(DisplayText) {} 71 72 /// The text to insert. If the user has already input some of the 73 /// completion, this should only include the rest of the text. 74 std::string TypedText; 75 76 /// A description of this completion. This may be the completion itself, or 77 /// maybe a summary of its type or arguments. 78 std::string DisplayText; 79 }; 80 81 /// Set the completer for this LineEditor. A completer is a function object 82 /// which takes arguments of type StringRef (the string to complete) and 83 /// size_t (the zero-based cursor position in the StringRef) and returns a 84 /// CompletionAction. 85 template <typename T> void setCompleter(T Comp) { 86 Completer.reset(new CompleterModel<T>(Comp)); 87 } 88 89 /// Set the completer for this LineEditor to the given list completer. 90 /// A list completer is a function object which takes arguments of type 91 /// StringRef (the string to complete) and size_t (the zero-based cursor 92 /// position in the StringRef) and returns a std::vector<Completion>. 93 template <typename T> void setListCompleter(T Comp) { 94 Completer.reset(new ListCompleterModel<T>(Comp)); 95 } 96 97 /// Use the current completer to produce a CompletionAction for the given 98 /// completion request. If the current completer is a list completer, this 99 /// will return an AK_Insert CompletionAction if each completion has a common 100 /// prefix, or an AK_ShowCompletions CompletionAction otherwise. 101 /// 102 /// \param Buffer The string to complete 103 /// \param Pos The zero-based cursor position in the StringRef 104 CompletionAction getCompletionAction(StringRef Buffer, size_t Pos) const; 105 106 const std::string &getPrompt() const { return Prompt; } 107 void setPrompt(const std::string &P) { Prompt = P; } 108 109 // Public so callbacks in LineEditor.cpp can use it. 110 struct InternalData; 111 112 private: 113 std::string Prompt; 114 std::string HistoryPath; 115 std::unique_ptr<InternalData> Data; 116 117 struct CompleterConcept { 118 virtual ~CompleterConcept(); 119 virtual CompletionAction complete(StringRef Buffer, size_t Pos) const = 0; 120 }; 121 122 struct ListCompleterConcept : CompleterConcept { 123 ~ListCompleterConcept() override; 124 CompletionAction complete(StringRef Buffer, size_t Pos) const override; 125 static std::string getCommonPrefix(const std::vector<Completion> &Comps); 126 virtual std::vector<Completion> getCompletions(StringRef Buffer, 127 size_t Pos) const = 0; 128 }; 129 130 template <typename T> 131 struct CompleterModel : CompleterConcept { 132 CompleterModel(T Value) : Value(Value) {} 133 CompletionAction complete(StringRef Buffer, size_t Pos) const override { 134 return Value(Buffer, Pos); 135 } 136 T Value; 137 }; 138 139 template <typename T> 140 struct ListCompleterModel : ListCompleterConcept { 141 ListCompleterModel(T Value) : Value(std::move(Value)) {} 142 std::vector<Completion> getCompletions(StringRef Buffer, 143 size_t Pos) const override { 144 return Value(Buffer, Pos); 145 } 146 T Value; 147 }; 148 149 std::unique_ptr<const CompleterConcept> Completer; 150 }; 151 152 } 153 154 #endif 155