clang-tools-extra/clangd/index/SymbolLocation.h

   1 //===--- SymbolLocation.h ----------------------------------------*- 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_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOLLOCATION_H
  10 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOLLOCATION_H
  11
  12 #include "llvm/ADT/StringRef.h"
  13 #include "llvm/Support/raw_ostream.h"
  14 #include <cstdint>
  15
  16 namespace clang {
  17 namespace clangd {
  18
  19 struct SymbolLocation {
  20   // Specify a position (Line, Column) of symbol. Using Line/Column allows us to
  21   // build LSP responses without reading the file content.
  22   //
  23   // clangd uses the following definitions, which differ slightly from LSP:
  24   //  - Line is the number of newline characters (\n) before the point.
  25   //  - Column is (by default) the number of UTF-16 code between the last \n
  26   //    (or start of file) and the point.
  27   //    If the `offsetEncoding` protocol extension is used to negotiate UTF-8,
  28   //    then it is instead the number of *bytes* since the last \n.
  29   //
  30   // Position is encoded into 32 bits to save space.
  31   // If Line/Column overflow, the value will be their maximum value.
  32   struct Position {
  33     Position() = default;
  34     void setLine(uint32_t Line);
  35     uint32_t line() const { return LineColumnPacked >> ColumnBits; }
  36     void setColumn(uint32_t Column);
  37     uint32_t column() const { return LineColumnPacked & MaxColumn; }
  38     uint32_t rep() const { return LineColumnPacked; }
  39
  40     bool hasOverflow() const {
  41       return line() == MaxLine || column() == MaxColumn;
  42     }
  43
  44     static constexpr unsigned ColumnBits = 12;
  45     static constexpr uint32_t MaxLine = (1 << (32 - ColumnBits)) - 1;
  46     static constexpr uint32_t MaxColumn = (1 << ColumnBits) - 1;
  47
  48   private:
  49     uint32_t LineColumnPacked = 0; // Top 20 bit line, bottom 12 bits column.
  50   };
  51
  52   /// The symbol range, using half-open range [Start, End).
  53   Position Start;
  54   Position End;
  55
  56   explicit operator bool() const { return !llvm::StringRef(FileURI).empty(); }
  57
  58   // The URI of the source file where a symbol occurs.
  59   // The string must be null-terminated.
  60   //
  61   // We avoid using llvm::StringRef here to save memory.
  62   // WARNING: unless you know what you are doing, it is recommended to use it
  63   // via llvm::StringRef.
  64   const char *FileURI = "";
  65 };
  66
  67 inline bool operator==(const SymbolLocation::Position &L,
  68                        const SymbolLocation::Position &R) {
  69   return std::make_tuple(L.line(), L.column()) ==
  70          std::make_tuple(R.line(), R.column());
  71 }
  72 inline bool operator<(const SymbolLocation::Position &L,
  73                       const SymbolLocation::Position &R) {
  74   return std::make_tuple(L.line(), L.column()) <
  75          std::make_tuple(R.line(), R.column());
  76 }
  77 inline bool operator==(const SymbolLocation &L, const SymbolLocation &R) {
  78   assert(L.FileURI && R.FileURI);
  79   return !std::strcmp(L.FileURI, R.FileURI) &&
  80          std::tie(L.Start, L.End) == std::tie(R.Start, R.End);
  81 }
  82 inline bool operator<(const SymbolLocation &L, const SymbolLocation &R) {
  83   assert(L.FileURI && R.FileURI);
  84   int Cmp = std::strcmp(L.FileURI, R.FileURI);
  85   if (Cmp != 0)
  86     return Cmp < 0;
  87   return std::tie(L.Start, L.End) < std::tie(R.Start, R.End);
  88 }
  89
  90 llvm::raw_ostream &operator<<(llvm::raw_ostream &, const SymbolLocation &);
  91
  92 } // namespace clangd
  93 } // namespace clang
  94
  95 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_SYMBOLLOCATION_H