1 //===- JSONCompilationDatabase.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 //  The JSONCompilationDatabase finds compilation databases supplied as a file
10 //  'compile_commands.json'.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_TOOLING_JSONCOMPILATIONDATABASE_H
15 #define LLVM_CLANG_TOOLING_JSONCOMPILATIONDATABASE_H
16 
17 #include "clang/Basic/LLVM.h"
18 #include "clang/Tooling/CompilationDatabase.h"
19 #include "clang/Tooling/FileMatchTrie.h"
20 #include "llvm/ADT/ArrayRef.h"
21 #include "llvm/ADT/StringMap.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/Support/MemoryBuffer.h"
24 #include "llvm/Support/SourceMgr.h"
25 #include "llvm/Support/YAMLParser.h"
26 #include <memory>
27 #include <string>
28 #include <tuple>
29 #include <utility>
30 #include <vector>
31 
32 namespace clang {
33 namespace tooling {
34 
35 /// A JSON based compilation database.
36 ///
37 /// JSON compilation database files must contain a list of JSON objects which
38 /// provide the command lines in the attributes 'directory', 'command',
39 /// 'arguments' and 'file':
40 /// [
41 ///   { "directory": "<working directory of the compile>",
42 ///     "command": "<compile command line>",
43 ///     "file": "<path to source file>"
44 ///   },
45 ///   { "directory": "<working directory of the compile>",
46 ///     "arguments": ["<raw>", "<command>" "<line>" "<parameters>"],
47 ///     "file": "<path to source file>"
48 ///   },
49 ///   ...
50 /// ]
51 /// Each object entry defines one compile action. The specified file is
52 /// considered to be the main source file for the translation unit.
53 ///
54 /// 'command' is a full command line that will be unescaped.
55 ///
56 /// 'arguments' is a list of command line arguments that will not be unescaped.
57 ///
58 /// JSON compilation databases can for example be generated in CMake projects
59 /// by setting the flag -DCMAKE_EXPORT_COMPILE_COMMANDS.
60 enum class JSONCommandLineSyntax { Windows, Gnu, AutoDetect };
61 class JSONCompilationDatabase : public CompilationDatabase {
62 public:
63   /// Loads a JSON compilation database from the specified file.
64   ///
65   /// Returns NULL and sets ErrorMessage if the database could not be
66   /// loaded from the given file.
67   static std::unique_ptr<JSONCompilationDatabase>
68   loadFromFile(StringRef FilePath, std::string &ErrorMessage,
69                JSONCommandLineSyntax Syntax);
70 
71   /// Loads a JSON compilation database from a data buffer.
72   ///
73   /// Returns NULL and sets ErrorMessage if the database could not be loaded.
74   static std::unique_ptr<JSONCompilationDatabase>
75   loadFromBuffer(StringRef DatabaseString, std::string &ErrorMessage,
76                  JSONCommandLineSyntax Syntax);
77 
78   /// Returns all compile commands in which the specified file was
79   /// compiled.
80   ///
81   /// FIXME: Currently FilePath must be an absolute path inside the
82   /// source directory which does not have symlinks resolved.
83   std::vector<CompileCommand>
84   getCompileCommands(StringRef FilePath) const override;
85 
86   /// Returns the list of all files available in the compilation database.
87   ///
88   /// These are the 'file' entries of the JSON objects.
89   std::vector<std::string> getAllFiles() const override;
90 
91   /// Returns all compile commands for all the files in the compilation
92   /// database.
93   std::vector<CompileCommand> getAllCompileCommands() const override;
94 
95 private:
96   /// Constructs a JSON compilation database on a memory buffer.
97   JSONCompilationDatabase(std::unique_ptr<llvm::MemoryBuffer> Database,
98                           JSONCommandLineSyntax Syntax)
99       : Database(std::move(Database)), Syntax(Syntax),
100         YAMLStream(this->Database->getBuffer(), SM) {}
101 
102   /// Parses the database file and creates the index.
103   ///
104   /// Returns whether parsing succeeded. Sets ErrorMessage if parsing
105   /// failed.
106   bool parse(std::string &ErrorMessage);
107 
108   // Tuple (directory, filename, commandline, output) where 'commandline'
109   // points to the corresponding scalar nodes in the YAML stream.
110   // If the command line contains a single argument, it is a shell-escaped
111   // command line.
112   // Otherwise, each entry in the command line vector is a literal
113   // argument to the compiler.
114   // The output field may be a nullptr.
115   using CompileCommandRef =
116       std::tuple<llvm::yaml::ScalarNode *, llvm::yaml::ScalarNode *,
117                  std::vector<llvm::yaml::ScalarNode *>,
118                  llvm::yaml::ScalarNode *>;
119 
120   /// Converts the given array of CompileCommandRefs to CompileCommands.
121   void getCommands(ArrayRef<CompileCommandRef> CommandsRef,
122                    std::vector<CompileCommand> &Commands) const;
123 
124   // Maps file paths to the compile command lines for that file.
125   llvm::StringMap<std::vector<CompileCommandRef>> IndexByFile;
126 
127   /// All the compile commands in the order that they were provided in the
128   /// JSON stream.
129   std::vector<CompileCommandRef> AllCommands;
130 
131   FileMatchTrie MatchTrie;
132 
133   std::unique_ptr<llvm::MemoryBuffer> Database;
134   JSONCommandLineSyntax Syntax;
135   llvm::SourceMgr SM;
136   llvm::yaml::Stream YAMLStream;
137 };
138 
139 } // namespace tooling
140 } // namespace clang
141 
142 #endif // LLVM_CLANG_TOOLING_JSONCOMPILATIONDATABASE_H
143