Annotation of parser3/src/main/pa_sql_driver_manager.C, revision 1.48
1.29 parser 1: /** @file
2: Parser: sql driver manager implementation.
3:
4: Copyright (c) 2001 ArtLebedev Group (http://www.artlebedev.com)
1.38 parser 5: Author: Alexander Petrosyan <paf@design.ru> (http://design.ru/paf)
1.29 parser 6:
1.48 ! paf 7: $Id: pa_sql_driver_manager.C,v 1.47 2001/10/31 14:42:05 paf Exp $
1.29 parser 8: */
9:
10: #include "pa_sql_driver_manager.h"
11: #include "ltdl.h"
12: #include "pa_sql_connection.h"
13: #include "pa_exception.h"
14: #include "pa_common.h"
15: #include "pa_threads.h"
1.42 parser 16: #include "pa_stack.h"
1.29 parser 17:
18: // globals
19:
20: SQL_Driver_manager *SQL_driver_manager;
21:
22: // consts
23:
24: const int EXPIRE_UNUSED_CONNECTION_SECONDS=60;
1.30 parser 25: const int CHECK_EXPIRED_CONNECTIONS_SECONDS=EXPIRE_UNUSED_CONNECTION_SECONDS*2;
1.29 parser 26:
27:
28: /// SQL_Driver_services Pooled implementation
29: class SQL_Driver_services_impl : public SQL_Driver_services, public Pooled {
30: public:
31: SQL_Driver_services_impl(Pool& apool, const String& aurl) : Pooled(apool),
32: furl(aurl) {
33: }
1.40 parser 34:
1.45 paf 35: virtual void *malloc(size_t size) { return Pooled::malloc(size, 8); }
1.43 paf 36: virtual void *calloc(size_t size) { return Pooled::calloc(size); }
37:
38: /**
39: the idea is to #1 jump to C++ some function to main body, where
40: every function stack frame has exception unwind information
41: and from there... #2 propagate_exception()
42: */
43: virtual void _throw(const char *comment) {
1.47 paf 44: String& protocol=*NEW String(pool());
45: /// hiding passwords and addresses from accidental show [imagine user forgot @exception]
1.48 ! paf 46: protocol << furl.mid(0, furl.pos(":")) << "://****";
1.43 paf 47: e=Exception(0, 0,
1.47 paf 48: &protocol,
1.29 parser 49: comment);
1.43 paf 50:
51: longjmp(mark, 1);
52: }
53: virtual void propagate_exception() {
54: throw e;
1.29 parser 55: }
56:
57: private:
58: const String& furl;
1.43 paf 59: Exception e;
1.29 parser 60: };
61:
1.42 parser 62: // helpers
63:
64: static void expire_connection(Array::Item *value, void *info) {
65: SQL_Connection& connection=*static_cast<SQL_Connection *>(value);
66: time_t older_dies=reinterpret_cast<time_t>(info);
67:
68: if(connection.connected() && connection.expired(older_dies))
69: connection.disconnect();
70: }
71: static void expire_connections(const Hash::Key& key, Hash::Val *value, void *info) {
72: Stack& stack=*static_cast<Stack *>(value);
73: for(int i=0; i<=stack.top_index(); i++)
74: expire_connection(stack.get(i), info);
75: }
76:
1.29 parser 77: // SQL_Driver_manager
78:
1.42 parser 79: SQL_Driver_manager::SQL_Driver_manager(Pool& pool) : Pooled(pool),
80: driver_cache(pool),
81: connection_cache(pool),
82: prev_expiration_pass_time(0) {
83:
84: }
85:
86: SQL_Driver_manager::~SQL_Driver_manager() {
87: connection_cache.for_each(expire_connections,
88: reinterpret_cast<void *>((time_t)0/*=in past=expire all*/));
89: }
90:
1.29 parser 91: /// @param request_url protocol://[driver-dependent]
1.36 parser 92: SQL_Connection& SQL_Driver_manager::get_connection(const String& request_url,
93: const String& request_origin,
1.29 parser 94: Table *protocol2driver_and_client) {
1.36 parser 95: Pool& pool=request_origin.pool(); // request pool
1.29 parser 96:
97: // we have table for locating protocol's library
98: if(!protocol2driver_and_client)
1.41 parser 99: throw Exception(0, 0,
1.29 parser 100: &request_url,
1.31 parser 101: "$"MAIN_SQL_NAME":"MAIN_SQL_DRIVERS_NAME" table must be defined");
1.29 parser 102:
1.44 paf 103: // construct services[request] (deassociates at close)
104: SQL_Driver_services *services=new(pool) SQL_Driver_services_impl(pool, request_url);
105:
1.29 parser 106: // first trying to get cached connection
107: SQL_Connection *result=get_connection_from_cache(request_url);
1.44 paf 108: if(result) {
109: result->set_services(services);
110: if(!result->ping()) { // we have some cached connection, is it pingable?
111: result->disconnect(); // kill unpingabe=dead connection
112: result=0;
113: }
1.29 parser 114: }
115:
116: char *request_url_cstr;
117: if(result)
118: request_url_cstr=0; // calm, compiler
119: else { // no cached connection or it were unpingabe: connect/reconnect
120: int pos=request_url.pos("://", 3);
121: if(pos<0)
1.41 parser 122: throw Exception(0, 0,
1.36 parser 123: request_url.size()?&request_url:&request_origin,
124: "connection string must start with protocol://"); // NOTE: not THROW, but PTHROW
1.29 parser 125:
126: // make global_url C-string on global pool
1.46 paf 127: request_url_cstr=request_url.cstr();
1.29 parser 128: char *global_url_cstr=(char *)malloc(strlen(request_url_cstr)+1);
129: strcpy(global_url_cstr, request_url_cstr);
130: // make global_url string on global pool
131: String& global_url=*new(this->pool()) String(this->pool(), global_url_cstr);
132:
133: char *request_protocol_cstr=lsplit(&request_url_cstr, ':');
134: // skip "//" after ':'
135: while(*request_url_cstr=='/')
136: request_url_cstr++;
137: // make global_protocol C-string on global pool
138: char *global_protocol_cstr=(char *)malloc(strlen(request_protocol_cstr)+1);
139: strcpy(global_protocol_cstr, request_protocol_cstr);
140: // make global_protocol string on global pool
141: String& global_protocol=*new(this->pool()) String(this->pool(),
142: global_protocol_cstr);
143:
144: SQL_Driver *driver;
145: const String *dlopen_file_spec=0;
146: // first trying to get cached driver
147: if(!(driver=get_driver_from_cache(global_protocol))) {
148: // no cached
149: const String *library=0;
150: if(protocol2driver_and_client->locate(0, global_protocol)) {
151: if(!(library=protocol2driver_and_client->item(1)) || library->size()==0)
1.41 parser 152: throw Exception(0, 0,
1.29 parser 153: protocol2driver_and_client->origin_string(),
154: "driver library column for protocol '%s' is empty",
155: request_protocol_cstr);
156: dlopen_file_spec=protocol2driver_and_client->item(2);
157: } else
1.41 parser 158: throw Exception(0, 0,
1.29 parser 159: &request_url,
160: "undefined protocol '%s'",
161: request_protocol_cstr);
162:
163: if(lt_dlinit())
1.41 parser 164: throw Exception(0, 0,
1.29 parser 165: library,
166: "prepare to dynamic loading failed, %s", lt_dlerror());
167:
1.34 parser 168: const char *filename=library->cstr(String::UL_FILE_SPEC);
1.29 parser 169: lt_dlhandle handle=lt_dlopen(filename);
170: if (!handle)
1.41 parser 171: throw Exception(0, 0,
1.29 parser 172: library,
173: "can not open the module, %s", lt_dlerror());
174:
175: SQL_Driver_create_func create=(SQL_Driver_create_func)lt_dlsym(handle,
1.33 parser 176: SQL_DRIVER_CREATE_NAME);
1.29 parser 177: if(!create)
1.41 parser 178: throw Exception(0, 0,
1.29 parser 179: library,
1.33 parser 180: "function '"SQL_DRIVER_CREATE_NAME"' was not found");
1.29 parser 181:
182: // create library-driver!
183: driver=(*create)();
184:
185: // validate driver api version
186: int driver_api_version=driver->api_version();
187: if(driver_api_version!=SQL_DRIVER_API_VERSION)
1.41 parser 188: throw Exception(0, 0,
1.29 parser 189: library,
190: "driver implements API version 0x%04X not equal to 0x%04X",
191: driver_api_version, SQL_DRIVER_API_VERSION);
192:
193: // initialise by connecting to sql client dynamic link library
194: bool specified_dlopen_file_spec=dlopen_file_spec && dlopen_file_spec->size();
195: const char *dlopen_file_spec_cstr=
196: specified_dlopen_file_spec?
1.34 parser 197: dlopen_file_spec->cstr(String::UL_FILE_SPEC):0;
1.29 parser 198: if(const char *error=driver->initialize(
199: dlopen_file_spec_cstr))
1.41 parser 200: throw Exception(0, 0,
1.29 parser 201: library,
202: "driver failed to initialize client library '%s', %s",
203: specified_dlopen_file_spec?dlopen_file_spec_cstr:"unspecifed",
204: error);
205:
206: // cache it
207: put_driver_to_cache(global_protocol, *driver);
208: }
209:
210: // allocate in global pool
211: // associate with services[request]
212: // NOTE: never freed up!
213: result=new(this->pool()) SQL_Connection(this->pool(), global_url, *driver);
1.44 paf 214: // associate with services[request] (deassociates at close)
215: result->set_services(services);
1.29 parser 216: }
217:
218: // if not connected yet, do that now, when result has services
219: if(!result->connected())
220: result->connect(request_url_cstr);
221: // return it
222: return *result;
223: }
224:
225: void SQL_Driver_manager::close_connection(const String& url,
226: SQL_Connection& connection) {
227: // deassociate from services[request]
228: connection.set_services(0);
229: put_connection_to_cache(url, connection);
230: }
231:
232:
233: // driver cache
234:
235: SQL_Driver *SQL_Driver_manager::get_driver_from_cache(const String& protocol) {
236: SYNCHRONIZED;
237:
238: return static_cast<SQL_Driver *>(driver_cache.get(protocol));
239: }
240:
241: void SQL_Driver_manager::put_driver_to_cache(const String& protocol,
242: SQL_Driver& driver) {
243: SYNCHRONIZED;
244:
245: driver_cache.put(protocol, &driver);
246: }
247:
248: // connection cache
249: /// @todo get rid of memory spending Stack [zeros deep inside got accumulated]
250: SQL_Connection *SQL_Driver_manager::get_connection_from_cache(const String& url) {
251: SYNCHRONIZED;
252:
253: maybe_expire_connection_cache();
254:
255: if(Stack *connections=static_cast<Stack *>(connection_cache.get(url)))
256: while(connections->top_index()>=0) { // there are cached connections to that 'url'
257: SQL_Connection *result=static_cast<SQL_Connection *>(connections->pop());
258: if(result->connected()) // not expired?
259: return result;
260: }
261:
262: return 0;
263: }
264:
265: void SQL_Driver_manager::put_connection_to_cache(const String& url,
266: SQL_Connection& connection) {
267: SYNCHRONIZED;
268:
269: Stack *connections=static_cast<Stack *>(connection_cache.get(url));
270: if(!connections) { // there are no cached connections to that 'url' yet?
271: connections=NEW Stack(pool()); // NOTE: never freed up!
272: connection_cache.put(url, connections);
273: }
274: connections->push(&connection);
275: }
276:
277: void SQL_Driver_manager::maybe_expire_connection_cache() {
278: time_t now=time(0);
279:
280: if(prev_expiration_pass_time<now-CHECK_EXPIRED_CONNECTIONS_SECONDS) {
281: connection_cache.for_each(expire_connections,
282: reinterpret_cast<void *>(now-EXPIRE_UNUSED_CONNECTION_SECONDS));
283:
284: prev_expiration_pass_time=now;
285: }
286: }
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