1 //===- CXString.cpp - Routines for manipulating CXStrings -----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines routines for manipulating CXStrings. It should be the
11 // only file that has internal knowledge of the encoding of the data in
12 // CXStrings.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "CXString.h"
17 #include "CXTranslationUnit.h"
18 #include "clang-c/Index.h"
19 #include "clang/Frontend/ASTUnit.h"
20 #include "llvm/ADT/SmallString.h"
21 #include "llvm/Support/ErrorHandling.h"
22 
23 using namespace clang;
24 
25 /// Describes the kind of underlying data in CXString.
26 enum CXStringFlag {
27   /// CXString contains a 'const char *' that it doesn't own.
28   CXS_Unmanaged,
29 
30   /// CXString contains a 'const char *' that it allocated with malloc().
31   CXS_Malloc,
32 
33   /// CXString contains a CXStringBuf that needs to be returned to the
34   /// CXStringPool.
35   CXS_StringBuf
36 };
37 
38 namespace clang {
39 namespace cxstring {
40 
41 //===----------------------------------------------------------------------===//
42 // Basic generation of CXStrings.
43 //===----------------------------------------------------------------------===//
44 
45 CXString createEmpty() {
46   CXString Str;
47   Str.data = "";
48   Str.private_flags = CXS_Unmanaged;
49   return Str;
50 }
51 
52 CXString createNull() {
53   CXString Str;
54   Str.data = 0;
55   Str.private_flags = CXS_Unmanaged;
56   return Str;
57 }
58 
59 CXString createRef(const char *String) {
60   if (String && String[0] == '\0')
61     return createEmpty();
62 
63   CXString Str;
64   Str.data = String;
65   Str.private_flags = CXS_Unmanaged;
66   return Str;
67 }
68 
69 CXString createDup(const char *String) {
70   if (!String)
71     return createNull();
72 
73   if (String[0] == '\0')
74     return createEmpty();
75 
76   CXString Str;
77   Str.data = strdup(String);
78   Str.private_flags = CXS_Malloc;
79   return Str;
80 }
81 
82 CXString createRef(StringRef String) {
83   // If the string is not nul-terminated, we have to make a copy.
84   // This is doing a one past end read, and should be removed!
85   if (!String.empty() && String.data()[String.size()] != 0)
86     return createDup(String);
87 
88   CXString Result;
89   Result.data = String.data();
90   Result.private_flags = (unsigned) CXS_Unmanaged;
91   return Result;
92 }
93 
94 CXString createDup(StringRef String) {
95   CXString Result;
96   char *Spelling = static_cast<char *>(malloc(String.size() + 1));
97   memmove(Spelling, String.data(), String.size());
98   Spelling[String.size()] = 0;
99   Result.data = Spelling;
100   Result.private_flags = (unsigned) CXS_Malloc;
101   return Result;
102 }
103 
104 CXString createCXString(CXStringBuf *buf) {
105   CXString Str;
106   Str.data = buf;
107   Str.private_flags = (unsigned) CXS_StringBuf;
108   return Str;
109 }
110 
111 
112 //===----------------------------------------------------------------------===//
113 // String pools.
114 //===----------------------------------------------------------------------===//
115 
116 CXStringPool::~CXStringPool() {
117   for (std::vector<CXStringBuf *>::iterator I = Pool.begin(), E = Pool.end();
118        I != E; ++I) {
119     delete *I;
120   }
121 }
122 
123 CXStringBuf *CXStringPool::getCXStringBuf(CXTranslationUnit TU) {
124   if (Pool.empty())
125     return new CXStringBuf(TU);
126 
127   CXStringBuf *Buf = Pool.back();
128   Buf->Data.clear();
129   Pool.pop_back();
130   return Buf;
131 }
132 
133 CXStringBuf *getCXStringBuf(CXTranslationUnit TU) {
134   return TU->StringPool->getCXStringBuf(TU);
135 }
136 
137 void CXStringBuf::dispose() {
138   TU->StringPool->Pool.push_back(this);
139 }
140 
141 bool isManagedByPool(CXString str) {
142   return ((CXStringFlag) str.private_flags) == CXS_StringBuf;
143 }
144 
145 } // end namespace cxstring
146 } // end namespace clang
147 
148 //===----------------------------------------------------------------------===//
149 // libClang public APIs.
150 //===----------------------------------------------------------------------===//
151 
152 extern "C" {
153 const char *clang_getCString(CXString string) {
154   if (string.private_flags == (unsigned) CXS_StringBuf) {
155     return static_cast<const cxstring::CXStringBuf *>(string.data)->Data.data();
156   }
157   return static_cast<const char *>(string.data);
158 }
159 
160 void clang_disposeString(CXString string) {
161   switch ((CXStringFlag) string.private_flags) {
162     case CXS_Unmanaged:
163       break;
164     case CXS_Malloc:
165       if (string.data)
166         free(const_cast<void *>(string.data));
167       break;
168     case CXS_StringBuf:
169       static_cast<cxstring::CXStringBuf *>(
170           const_cast<void *>(string.data))->dispose();
171       break;
172   }
173 }
174 } // end: extern "C"
175 
176