1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _EXPRESSION_H
#define _EXPRESSION_H
#include <unistd.h>
#include "yydefs.h"
#ifdef __cplusplus
extern "C" {
#endif
#define MAX_STRING_LEN 1024
typedef struct Expr Expr;
typedef struct {
// Optional pointer to app-specific data; the core of edify never
// uses this value.
void* cookie;
// The source of the original script. Must be NULL-terminated,
// and in writable memory (Evaluate may make temporary changes to
// it but will restore it when done).
char* script;
// The error message (if any) returned if the evaluation aborts.
// Should be NULL initially, will be either NULL or a malloc'd
// pointer after Evaluate() returns.
char* errmsg;
} State;
#define VAL_STRING 1 // data will be NULL-terminated; size doesn't count null
#define VAL_BLOB 2
typedef struct {
int type;
ssize_t size;
char* data;
} Value;
typedef Value* (*Function)(const char* name, State* state,
int argc, Expr* argv[]);
struct Expr {
Function fn;
char* name;
int argc;
Expr** argv;
int start, end;
};
// Take one of the Expr*s passed to the function as an argument,
// evaluate it, return the resulting Value. The caller takes
// ownership of the returned Value.
Value* EvaluateValue(State* state, Expr* expr);
// Take one of the Expr*s passed to the function as an argument,
// evaluate it, assert that it is a string, and return the resulting
// char*. The caller takes ownership of the returned char*. This is
// a convenience function for older functions that want to deal only
// with strings.
char* Evaluate(State* state, Expr* expr);
// Glue to make an Expr out of a literal.
Value* Literal(const char* name, State* state, int argc, Expr* argv[]);
// Functions corresponding to various syntactic sugar operators.
// ("concat" is also available as a builtin function, to concatenate
// more than two strings.)
Value* ConcatFn(const char* name, State* state, int argc, Expr* argv[]);
Value* LogicalAndFn(const char* name, State* state, int argc, Expr* argv[]);
Value* LogicalOrFn(const char* name, State* state, int argc, Expr* argv[]);
Value* LogicalNotFn(const char* name, State* state, int argc, Expr* argv[]);
Value* SubstringFn(const char* name, State* state, int argc, Expr* argv[]);
Value* EqualityFn(const char* name, State* state, int argc, Expr* argv[]);
Value* InequalityFn(const char* name, State* state, int argc, Expr* argv[]);
Value* SequenceFn(const char* name, State* state, int argc, Expr* argv[]);
// Convenience function for building expressions with a fixed number
// of arguments.
Expr* Build(Function fn, YYLTYPE loc, int count, ...);
// Global builtins, registered by RegisterBuiltins().
Value* IfElseFn(const char* name, State* state, int argc, Expr* argv[]);
Value* AssertFn(const char* name, State* state, int argc, Expr* argv[]);
Value* AbortFn(const char* name, State* state, int argc, Expr* argv[]);
// For setting and getting the global error string (when returning
// NULL from a function).
void SetError(const char* message); // makes a copy
const char* GetError(); // retains ownership
void ClearError();
typedef struct {
const char* name;
Function fn;
} NamedFunction;
// Register a new function. The same Function may be registered under
// multiple names, but a given name should only be used once.
void RegisterFunction(const char* name, Function fn);
// Register all the builtins.
void RegisterBuiltins();
// Call this after all calls to RegisterFunction() but before parsing
// any scripts to finish building the function table.
void FinishRegistration();
// Find the Function for a given name; return NULL if no such function
// exists.
Function FindFunction(const char* name);
// --- convenience functions for use in functions ---
// Evaluate the expressions in argv, giving 'count' char* (the ... is
// zero or more char** to put them in). If any expression evaluates
// to NULL, free the rest and return -1. Return 0 on success.
int ReadArgs(State* state, Expr* argv[], int count, ...);
// Evaluate the expressions in argv, giving 'count' Value* (the ... is
// zero or more Value** to put them in). If any expression evaluates
// to NULL, free the rest and return -1. Return 0 on success.
int ReadValueArgs(State* state, Expr* argv[], int count, ...);
// Evaluate the expressions in argv, returning an array of char*
// results. If any evaluate to NULL, free the rest and return NULL.
// The caller is responsible for freeing the returned array and the
// strings it contains.
char** ReadVarArgs(State* state, int argc, Expr* argv[]);
// Evaluate the expressions in argv, returning an array of Value*
// results. If any evaluate to NULL, free the rest and return NULL.
// The caller is responsible for freeing the returned array and the
// Values it contains.
Value** ReadValueVarArgs(State* state, int argc, Expr* argv[]);
// Use printf-style arguments to compose an error message to put into
// *state. Returns NULL.
Value* ErrorAbort(State* state, const char* format, ...) __attribute__((format(printf, 2, 3)));
// Wrap a string into a Value, taking ownership of the string.
Value* StringValue(char* str);
// Free a Value object.
void FreeValue(Value* v);
int parse_string(const char* str, Expr** root, int* error_count);
#ifdef __cplusplus
} // extern "C"
#endif
#endif // _EXPRESSION_H
|
