1 //===--- CommentCommandTraits.cpp - Comment command properties --*- 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 #include "clang/AST/CommentCommandTraits.h"
10 #include "llvm/ADT/STLExtras.h"
11 #include <cassert>
12 
13 namespace clang {
14 namespace comments {
15 
16 #include "clang/AST/CommentCommandInfo.inc"
17 
18 CommandTraits::CommandTraits(llvm::BumpPtrAllocator &Allocator,
19                              const CommentOptions &CommentOptions) :
20     NextID(llvm::array_lengthof(Commands)), Allocator(Allocator) {
21   registerCommentOptions(CommentOptions);
22 }
23 
24 void CommandTraits::registerCommentOptions(
25     const CommentOptions &CommentOptions) {
26   for (CommentOptions::BlockCommandNamesTy::const_iterator
27            I = CommentOptions.BlockCommandNames.begin(),
28            E = CommentOptions.BlockCommandNames.end();
29        I != E; I++) {
30     registerBlockCommand(*I);
31   }
32 }
33 
34 const CommandInfo *CommandTraits::getCommandInfoOrNULL(StringRef Name) const {
35   if (const CommandInfo *Info = getBuiltinCommandInfo(Name))
36     return Info;
37   return getRegisteredCommandInfo(Name);
38 }
39 
40 const CommandInfo *CommandTraits::getCommandInfo(unsigned CommandID) const {
41   if (const CommandInfo *Info = getBuiltinCommandInfo(CommandID))
42     return Info;
43   return getRegisteredCommandInfo(CommandID);
44 }
45 
46 const CommandInfo *
47 CommandTraits::getTypoCorrectCommandInfo(StringRef Typo) const {
48   // Single-character command impostures, such as \t or \n, should not go
49   // through the fixit logic.
50   if (Typo.size() <= 1)
51     return nullptr;
52 
53   // The maximum edit distance we're prepared to accept.
54   const unsigned MaxEditDistance = 1;
55 
56   unsigned BestEditDistance = MaxEditDistance;
57   SmallVector<const CommandInfo *, 2> BestCommand;
58 
59   auto ConsiderCorrection = [&](const CommandInfo *Command) {
60     StringRef Name = Command->Name;
61 
62     unsigned MinPossibleEditDistance = abs((int)Name.size() - (int)Typo.size());
63     if (MinPossibleEditDistance <= BestEditDistance) {
64       unsigned EditDistance = Typo.edit_distance(Name, true, BestEditDistance);
65       if (EditDistance < BestEditDistance) {
66         BestEditDistance = EditDistance;
67         BestCommand.clear();
68       }
69       if (EditDistance == BestEditDistance)
70         BestCommand.push_back(Command);
71     }
72   };
73 
74   for (const auto &Command : Commands)
75     ConsiderCorrection(&Command);
76 
77   for (const auto *Command : RegisteredCommands)
78     if (!Command->IsUnknownCommand)
79       ConsiderCorrection(Command);
80 
81   return BestCommand.size() == 1 ? BestCommand[0] : nullptr;
82 }
83 
84 CommandInfo *CommandTraits::createCommandInfoWithName(StringRef CommandName) {
85   char *Name = Allocator.Allocate<char>(CommandName.size() + 1);
86   memcpy(Name, CommandName.data(), CommandName.size());
87   Name[CommandName.size()] = '\0';
88 
89   // Value-initialize (=zero-initialize in this case) a new CommandInfo.
90   CommandInfo *Info = new (Allocator) CommandInfo();
91   Info->Name = Name;
92   // We only have a limited number of bits to encode command IDs in the
93   // CommandInfo structure, so the ID numbers can potentially wrap around.
94   assert((NextID < (1 << CommandInfo::NumCommandIDBits))
95          && "Too many commands. We have limited bits for the command ID.");
96   Info->ID = NextID++;
97 
98   RegisteredCommands.push_back(Info);
99 
100   return Info;
101 }
102 
103 const CommandInfo *CommandTraits::registerUnknownCommand(
104                                                   StringRef CommandName) {
105   CommandInfo *Info = createCommandInfoWithName(CommandName);
106   Info->IsUnknownCommand = true;
107   return Info;
108 }
109 
110 const CommandInfo *CommandTraits::registerBlockCommand(StringRef CommandName) {
111   CommandInfo *Info = createCommandInfoWithName(CommandName);
112   Info->IsBlockCommand = true;
113   return Info;
114 }
115 
116 const CommandInfo *CommandTraits::getBuiltinCommandInfo(
117                                                   unsigned CommandID) {
118   if (CommandID < llvm::array_lengthof(Commands))
119     return &Commands[CommandID];
120   return nullptr;
121 }
122 
123 const CommandInfo *CommandTraits::getRegisteredCommandInfo(
124                                                   StringRef Name) const {
125   for (unsigned i = 0, e = RegisteredCommands.size(); i != e; ++i) {
126     if (RegisteredCommands[i]->Name == Name)
127       return RegisteredCommands[i];
128   }
129   return nullptr;
130 }
131 
132 const CommandInfo *CommandTraits::getRegisteredCommandInfo(
133                                                   unsigned CommandID) const {
134   return RegisteredCommands[CommandID - llvm::array_lengthof(Commands)];
135 }
136 
137 } // end namespace comments
138 } // end namespace clang
139 
140