Annotation of parser3/src/include/pa_pool.h, revision 1.49
1.34 paf 1: /** @file
1.36 paf 2: Parser: pool class decl.
3:
1.27 paf 4: Copyright (c) 2001 ArtLebedev Group (http://www.artlebedev.com)
1.36 paf 5:
1.28 paf 6: Author: Alexander Petrosyan <paf@design.ru> (http://design.ru/paf)
1.27 paf 7:
1.49 ! paf 8: $Id: pa_pool.h,v 1.48 2001/04/04 06:16:19 paf Exp $
1.1 paf 9: */
10:
11: #ifndef PA_POOL_H
12: #define PA_POOL_H
13:
14: #include <stddef.h>
15:
1.21 paf 16: class Exception;
1.25 paf 17: class Temp_exception;
1.1 paf 18:
1.35 paf 19: /**
1.34 paf 20: Pool mechanizm allows users not to free up allocated memory,
21: leaving that problem to 'pools'.
22:
23: Also holds Exception object, which can be temporary set using
24: Temp_exception auto-object.
1.38 paf 25:
26: @see Pooled
1.34 paf 27: */
1.47 paf 28:
1.1 paf 29: class Pool {
1.25 paf 30: friend Temp_exception;
1.1 paf 31: public:
1.18 paf 32:
1.47 paf 33: Pool(void *astorage) : fstorage(astorage), fcontext(0), ftag(0), fexception(0) {}
1.18 paf 34:
1.40 paf 35: void set_context(void *acontext) { fcontext=acontext; }
36: void *context() { return fcontext; }
1.39 paf 37:
1.47 paf 38: void set_tag(void *atag) { ftag=atag; }
39: void *tag() { return ftag; }
1.44 paf 40:
1.34 paf 41: /// current exception object of the pool
1.31 paf 42: Exception& exception() const { return *fexception; }
1.18 paf 43:
1.34 paf 44: /// allocates some bytes on pool
1.18 paf 45: void *malloc(size_t size) {
46: return check(real_malloc(size), size);
47: }
1.34 paf 48: /// allocates some bytes clearing them with zeros
1.18 paf 49: void *calloc(size_t size) {
50: return check(real_calloc(size), size);
51: }
1.39 paf 52:
53: private:
54:
55: void *fstorage;
1.40 paf 56: void *fcontext;
1.47 paf 57: void *ftag;
1.8 paf 58:
1.23 paf 59: private: // implementation defined
1.18 paf 60:
1.20 paf 61: void *real_malloc(size_t size);
62: void *real_calloc(size_t size);
1.17 paf 63:
1.23 paf 64: private:
1.17 paf 65:
1.34 paf 66: /// checks whether mem allocated OK. throws exception otherwise
1.23 paf 67: void *check(void *ptr, size_t size) {
68: if(ptr)
69: return ptr;
70:
71: fail(size);
72:
73: // never reached
74: return 0;
75: }
1.34 paf 76: /// throws proper exception
1.23 paf 77: void fail(size_t size) const;
78:
1.34 paf 79: private: // exception handling
1.17 paf 80:
1.45 paf 81: // exception replacement mechanism is 'private'zed from direct usage
1.34 paf 82: // Temp_exception object enforces paired set/restore
1.23 paf 83: Exception *set_exception(Exception *e){
1.31 paf 84: Exception *r=fexception;
85: fexception=e;
1.23 paf 86: return r;
87: }
88: void restore_exception(Exception *e) {
1.31 paf 89: fexception=e;
1.23 paf 90: }
91:
92: private:
93:
94: // current request's exception object
1.31 paf 95: Exception *fexception;
1.17 paf 96:
1.8 paf 97: private: //disabled
98:
1.18 paf 99: // Pool(const Pool&) {}
1.16 paf 100: Pool& operator = (const Pool&) { return *this; }
1.21 paf 101: };
102:
1.35 paf 103: /**
1.34 paf 104: Base for all classes that are allocated in 'pools'.
105:
106: Holds Pool object. Contains useful wrappers to it's methods.
1.38 paf 107:
108: @see NEW, Temp_exception
1.34 paf 109: */
1.21 paf 110: class Pooled {
1.23 paf 111: // the pool i'm allocated on
1.49 ! paf 112: Pool *fpool;
1.21 paf 113: public:
1.37 paf 114:
115: /// the Pooled-sole: Pooled instances can be allocated in Pool rather then on heap
1.21 paf 116: static void *operator new(size_t size, Pool& apool) {
117: return apool.malloc(size);
118: }
119:
1.49 ! paf 120: Pooled(Pool& apool) : fpool(&apool) {}
1.23 paf 121:
1.34 paf 122: /// my pool
1.49 ! paf 123: Pool& pool() const { return *fpool; }
! 124:
! 125: /** used for moving objects from one pool to another.
! 126: in between object can have no pool and can not be used
! 127: @see SQL_Driver_manager
! 128: */
! 129: void set_pool(Pool *apool) { fpool=apool; }
1.21 paf 130:
1.34 paf 131: /// useful wrapper around pool
1.49 ! paf 132: void *malloc(size_t size) const { return fpool->malloc(size); }
1.34 paf 133: /// useful wrapper around pool
1.49 ! paf 134: void *calloc(size_t size) const { return fpool->calloc(size); }
1.34 paf 135: /// useful wrapper around pool
1.49 ! paf 136: Exception& exception() const { return fpool->exception(); }
1.23 paf 137: };
1.34 paf 138: /// useful macro for creating objects on current Pooled object Pooled::pool()
1.23 paf 139: #define NEW new(pool())
140:
1.35 paf 141: /**
1.34 paf 142: Auto-object used for temporary changing Pool's exception().
143:
144: Use by with these macros:
1.38 paf 145: @code
1.34 paf 146: TRY {
1.38 paf 147: // ...
1.34 paf 148: if(?)
149: THROW(?);
1.38 paf 150: // ...
1.34 paf 151: } CATCH(e) {
1.38 paf 152: // code, using e fields
153: // e.comment()
1.34 paf 154: }
155: END_CATCH
1.38 paf 156: @endcode
157:
158: @see TRY, THROW
1.34 paf 159: */
1.25 paf 160: class Temp_exception {
1.29 paf 161: Pool& fpool;
1.23 paf 162: Exception *saved_exception;
163: public:
1.25 paf 164: Temp_exception(Pool& apool, Exception& exception) :
1.29 paf 165: fpool(apool),
1.23 paf 166: saved_exception(apool.set_exception(&exception)) {
167: }
1.25 paf 168: ~Temp_exception() {
1.29 paf 169: fpool.restore_exception(saved_exception);
1.23 paf 170: }
1.1 paf 171: };
1.23 paf 172:
1.33 paf 173: #define XTRY(pool) \
1.24 paf 174: { \
175: Exception temp_exception; \
1.33 paf 176: Temp_exception le(pool, temp_exception); \
1.24 paf 177: if(setjmp(temp_exception.mark)==0)
1.31 paf 178:
1.33 paf 179: #define XTHROW(exception) exception._throw
180: #define XCATCH(e) \
1.24 paf 181: else{ \
182: Exception& e=temp_exception;
1.31 paf 183:
1.33 paf 184: #define XEND_CATCH \
1.24 paf 185: } \
186: }
1.33 paf 187:
1.34 paf 188: //@{
189: /// @see Temp_exception
1.33 paf 190: #define TRY XTRY(pool())
191: #define THROW XTHROW(exception())
192: #define CATCH(e) XCATCH(e)
193: #define END_CATCH XEND_CATCH
194:
195: #define PTRY XTRY(pool)
196: #define PTHROW XTHROW(pool.exception())
197: #define PCATCH(e) XCATCH(e)
198: #define PEND_CATCH XEND_CATCH
1.34 paf 199: //@}
1.1 paf 200:
201: #endif
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