# how to make nasty code less nasty (obtaining sqlite db handle) - Thread: https://externals.io/message/14597 - Original archive: https://news-web.php.net/php.internals/14597 - Started by Derrell.Lipman@UnwiredUniverse.com on 2005-02-03T22:03:45+00:00 - Messages: 7 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #14597 — Derrell.Lipman@UnwiredUniverse.com — 2005-02-03T22:03:45+00:00 URL: https://externals.io/message/14597#14597 I've written an extension which needs to accept a Resource which is an SQLite database handle, and call a C function which will be using that db handle to issue queries. What I've done works, but is kinda nasty because there doesn't appear to be a clean way to obtain that database handle nor, from what I can tell, determine the resource type to expect. Is there a nicer way of doing this? PHP_FUNCTION(my_PHP_function) { int id; int dataLen; int resourceType; char * pData; zval * zdb; void * hDB; void ** phDB; /* Ensure we got the correct number of parameters */ if (ZEND_NUM_ARGS() != 2) { WRONG_PARAM_COUNT; } /* Retrieve the parameters */ if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "rs", &zdb, &pData, &dataLen) == FAILURE) { return; } /* * Voodoo to retrieve the sqlite database handle from the resource. * How do I validate that resourceType is reasonable? */ id = zdb->value.lval; if ((phDB = zend_list_find(id, &resourceType)) == NULL) { return; } /* * This is nasty too. We "know" that the first field in the private * structure is the database handle. Just extract it. */ hDB = *phDB; RETURN_STRING(my_C_function(hDB, pData), TRUE); } Thanks, Derrell --- ## #14628 — Wez Furlong — 2005-02-04T01:36:58+00:00 URL: https://externals.io/message/14597#14628 · In reply to: #14597 There is no official way to do this kind of thing between arbitrary extensions. When extensions that are written to share this information, they typically export an XXX_API function that you can link against to fetch the data. What you've done works, so that's fine, although there is a risk of crashing if someone passes the wrong type of resource in. If you're thinking of distributing your extension, we could add a more official API for you to use, although that doesn't exist in older versions of the extension, etc. etc. Some time back, I proposed a framework (and even a patch IIRC) that allowed this kind of thing at run-time; despite "we the extension developers" liking the idea, there was some negative feedback from andi/zeev so it never went further. Search the php-dev archives for my name and "interfaces" for more on that if you're interesting in this seeing light in PHP 5.2. --Wez. On Thu, 03 Feb 2005 17:03:45 -0500, Derrell.Lipman@unwireduniverse.com wrote: > I've written an extension which needs to accept a Resource which is an SQLite > database handle, and call a C function which will be using that db handle to > issue queries. What I've done works, but is kinda nasty because there doesn't > appear to be a clean way to obtain that database handle nor, from what I can > tell, determine the resource type to expect. Is there a nicer way of doing > this? > > PHP_FUNCTION(my_PHP_function) > { > int id; > int dataLen; > int resourceType; > char * pData; > zval * zdb; > void * hDB; > void ** phDB; > > /* Ensure we got the correct number of parameters */ > if (ZEND_NUM_ARGS() != 2) > { > WRONG_PARAM_COUNT; > } > > /* Retrieve the parameters */ > if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, > "rs", > &zdb, &pData, &dataLen) == FAILURE) > { > return; > } > > /* > * Voodoo to retrieve the sqlite database handle from the resource. > * How do I validate that resourceType is reasonable? > */ > id = zdb->value.lval; > if ((phDB = zend_list_find(id, &resourceType)) == NULL) > { > return; > } > > /* > * This is nasty too. We "know" that the first field in the private > * structure is the database handle. Just extract it. > */ > hDB = *phDB; > > RETURN_STRING(my_C_function(hDB, pData), TRUE); > } > > Thanks, > > Derrell --- ## #14636 — Derrell.Lipman@UnwiredUniverse.com — 2005-02-04T03:56:04+00:00 URL: https://externals.io/message/14597#14636 · In reply to: #14628 Wez Furlong writes: > There is no official way to do this kind of thing between arbitrary > extensions. When extensions that are written to share this information, > they typically export an XXX_API function that you can link against to fetch > the data. > > What you've done works, so that's fine, although there is a risk of > crashing if someone passes the wrong type of resource in. If you're > thinking of distributing your extension, we could add a more official > API for you to use, although that doesn't exist in older versions of > the extension, etc. etc. Thanks, Wez. My extension will likely never be used other than with locally-written code. My biggest concern is making use of the incestual knowledge of the private php_sqlite_db structure and that the database handle is the first field in it. That structure may change in the future. My use of this is as a function used in a query -- sqlite_create_function() is used to allow a call to a php function which passes the database handle to the extension function. Prior to today, my extension had its own private database handle that it initialized on the MINIT function, but I was causing a deadlock by calling this function from within a query in PHP which called the extension which tried to issue additional queries using my private database handle in the extension. Passing in the php-derived handle is the only way of eliminating that deadlock. I wonder whether I'm really alone in wanting access to a database handle for extensions. It would seem appropriate to provide access to the C-level database handle given a PHP resources. That would eliminate the need to base an extenion on insestual knowledge of the database-specific extension. Thanks again, Derrell --- ## #14645 — Andrei Zmievski — 2005-02-04T21:39:49+00:00 URL: https://externals.io/message/14597#14645 · In reply to: #14628 > Some time back, I proposed a framework (and even a patch IIRC) that > allowed this kind of thing at run-time; despite "we the extension > developers" liking the idea, there was some negative feedback from > andi/zeev so it never went further. Search the php-dev archives for > my name and "interfaces" for more on that if you're interesting in > this seeing light in PHP 5.2. I'd definitely be interested in seeing the extension dependency framework in 5.2. - Andrei --- ## #14646 — Rasmus Lerdorf — 2005-02-04T21:46:47+00:00 URL: https://externals.io/message/14597#14646 · In reply to: #14645 Andrei Zmievski wrote: > > > > […] > > > I'd definitely be interested in seeing the extension dependency > framework in 5.2. We need it for the ext/libxml mess, for example. -Rasmus --- ## #14647 — Wez Furlong — 2005-02-04T21:51:38+00:00 URL: https://externals.io/message/14597#14647 · In reply to: #14645 The extension deps framework (that orders the initialization done in internal_functions.c) is already in HEAD; I was talking about the extension "interfaces" idea I proposed a fairly long time ago now (long enough that I can't remember how long ago). I remember you showing interest in that at that time. --Wez. > I'd definitely be interested in seeing the extension dependency > framework in 5.2. > > - Andrei --- ## #14648 — l0t3k — 2005-02-04T23:12:27+00:00 URL: https://externals.io/message/14597#14648 · In reply to: #14647 i found this http://www.zend.com/lists/php-dev/200204/msg01083.html "Wez Furlong" wrote in message news:4e89b42605020413515e6448e6@mail.gmail.com... > The extension deps framework (that orders the initialization done in > internal_functions.c) is already in HEAD; I was talking about the > extension "interfaces" idea I proposed a fairly long time ago now > (long enough that I can't remember how long ago). I remember you > showing interest in that at that time. > > --Wez.