1 // Copyright 2015 Google Inc. All rights reserved
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 // +build ignore
16
17 //#define ENABLE_TID_CHECK
18
19 #include "symtab.h"
20
21 #ifdef ENABLE_TID_CHECK
22 #include <pthread.h>
23 #endif
24 #include <string.h>
25
26 #include <unordered_map>
27
28 #include "log.h"
29 #include "strutil.h"
30 #include "var.h"
31
32 struct SymbolData {
SymbolDataSymbolData33 SymbolData() : gv(Var::Undefined()) {}
34
35 Var* gv;
36 };
37
38 vector<string*>* g_symbols;
39 static vector<SymbolData> g_symbol_data;
40
41 Symbol kEmptySym;
42 Symbol kShellSym;
43 Symbol kKatiReadonlySym;
44
Symbol(int v)45 Symbol::Symbol(int v) : v_(v) {}
46
PeekGlobalVar() const47 Var* Symbol::PeekGlobalVar() const {
48 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
49 return Var::Undefined();
50 }
51 return g_symbol_data[v_].gv;
52 }
53
GetGlobalVar() const54 Var* Symbol::GetGlobalVar() const {
55 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
56 g_symbol_data.resize(v_ + 1);
57 }
58 Var* v = g_symbol_data[v_].gv;
59 if (v->Origin() == VarOrigin::ENVIRONMENT ||
60 v->Origin() == VarOrigin::ENVIRONMENT_OVERRIDE) {
61 Vars::add_used_env_vars(*this);
62 }
63 return v;
64 }
65
SetGlobalVar(Var * v,bool is_override,bool * readonly) const66 void Symbol::SetGlobalVar(Var* v, bool is_override, bool* readonly) const {
67 if (static_cast<size_t>(v_) >= g_symbol_data.size()) {
68 g_symbol_data.resize(v_ + 1);
69 }
70 Var* orig = g_symbol_data[v_].gv;
71 if (orig->ReadOnly()) {
72 if (readonly != nullptr)
73 *readonly = true;
74 else
75 ERROR("*** cannot assign to readonly variable: %s", c_str());
76 return;
77 } else if (readonly != nullptr) {
78 *readonly = false;
79 }
80 if (!is_override && (orig->Origin() == VarOrigin::OVERRIDE ||
81 orig->Origin() == VarOrigin::ENVIRONMENT_OVERRIDE)) {
82 return;
83 }
84 if (orig->Origin() == VarOrigin::COMMAND_LINE &&
85 v->Origin() == VarOrigin::FILE) {
86 return;
87 }
88 if (orig->Origin() == VarOrigin::AUTOMATIC) {
89 ERROR("overriding automatic variable is not implemented yet");
90 }
91 if (orig->IsDefined())
92 delete orig;
93 g_symbol_data[v_].gv = v;
94 }
95
ScopedGlobalVar(Symbol name,Var * var)96 ScopedGlobalVar::ScopedGlobalVar(Symbol name, Var* var)
97 : name_(name), orig_(NULL) {
98 orig_ = name.GetGlobalVar();
99 g_symbol_data[name_.val()].gv = var;
100 }
101
~ScopedGlobalVar()102 ScopedGlobalVar::~ScopedGlobalVar() {
103 g_symbol_data[name_.val()].gv = orig_;
104 }
105
106 class Symtab {
107 public:
Symtab()108 Symtab() {
109 #ifdef ENABLE_TID_CHECK
110 tid_ = pthread_self();
111 #endif
112
113 CHECK(g_symbols == NULL);
114 g_symbols = &symbols_;
115
116 Symbol s = InternImpl("");
117 CHECK(s.v_ == 0);
118 CHECK(Intern("") == s);
119 char b[2];
120 b[1] = 0;
121 for (int i = 1; i < 256; i++) {
122 b[0] = i;
123 s = InternImpl(b);
124 CHECK(s.val() == i);
125 }
126
127 kEmptySym = Intern("");
128 kShellSym = Intern("SHELL");
129 kKatiReadonlySym = Intern(".KATI_READONLY");
130 }
131
~Symtab()132 ~Symtab() {
133 LOG_STAT("%zu symbols", symbols_.size());
134 for (string* s : symbols_)
135 delete s;
136 }
137
InternImpl(StringPiece s)138 Symbol InternImpl(StringPiece s) {
139 auto found = symtab_.find(s);
140 if (found != symtab_.end()) {
141 return found->second;
142 }
143 symbols_.push_back(new string(s.data(), s.size()));
144 Symbol sym = Symbol(symtab_.size());
145 bool ok = symtab_.emplace(*symbols_.back(), sym).second;
146 CHECK(ok);
147 return sym;
148 }
149
Intern(StringPiece s)150 Symbol Intern(StringPiece s) {
151 #ifdef ENABLE_TID_CHECK
152 if (tid_ != pthread_self())
153 abort();
154 #endif
155
156 if (s.size() <= 1) {
157 return Symbol(s.empty() ? 0 : (unsigned char)s[0]);
158 }
159 return InternImpl(s);
160 }
161
162 private:
163 unordered_map<StringPiece, Symbol> symtab_;
164 vector<string*> symbols_;
165 #ifdef ENABLE_TID_CHECK
166 pthread_t tid_;
167 #endif
168 };
169
170 static Symtab* g_symtab;
171
InitSymtab()172 void InitSymtab() {
173 g_symtab = new Symtab;
174 }
175
QuitSymtab()176 void QuitSymtab() {
177 delete g_symtab;
178 }
179
Intern(StringPiece s)180 Symbol Intern(StringPiece s) {
181 return g_symtab->Intern(s);
182 }
183
JoinSymbols(const vector<Symbol> & syms,const char * sep)184 string JoinSymbols(const vector<Symbol>& syms, const char* sep) {
185 vector<string> strs;
186 for (Symbol s : syms) {
187 strs.push_back(s.str());
188 }
189 return JoinStrings(strs, sep);
190 }
191