objective c - Crashes when copying SQLite db from bundle to documents and then querying -

-

this makes absolutely no sense (to me).

sqlite throw exc_bad_access errors randomly (on sqlite3_prepare_v2 line in db class) when querying when copy database bundle documents folder in background thread. but, if don't perform in background thread no crashes ever occur.

the reason want perform operation in thread is quite large (~150mb).

my didfinishlaunchingwithoptions looks - working script commented out below gcd thread:

- (bool)application:(uiapplication *)application didfinishlaunchingwithoptions:(nsdictionary *)launchoptions {     dispatch_queue_t setupdb = dispatch_queue_create("setupdb", null);     dispatch_async(setupdb, ^{         [db setup];          dispatch_async(dispatch_get_main_queue(), ^{             [db connect];             [[nsnotificationcenter defaultcenter] postnotificationname:@"databaseready" object:nil];         });     });  //  if using code, though, works fine //  [db setup]; //  [db connect]; //  [[nsnotificationcenter defaultcenter] postnotificationname:@"databaseready" object:nil];      return yes; }

the database class looks (_statement defined in .h):

@implementation db  static sqlite3  * _db; static nsstring * _dbpath;  + (bool)setup {     nsstring      * sqlbundlepath   = [[nsbundle mainbundle] pathforresource:@"db" oftype:@"sqlite"];     nsstring      * documentsfolder = nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes)[0];     nsstring      * sqldocumentpath = [[documentsfolder stringbyappendingpathcomponent:@"db"] stringbyappendingpathextension:@"sqlite"];     nsfilemanager * filemanager     = [nsfilemanager defaultmanager];      // make sure don't have database in our documents, don't want overwrite!     if (! [filemanager fileexistsatpath:sqldocumentpath]) {         bool success = [filemanager copyitematpath:sqlbundlepath topath:sqldocumentpath error:nil];          if (! success) {             nslog(@"error copying database");             return no;         }     }      _dbpath = sqldocumentpath;      return yes; }  + (bool)connect {     sqlite3_config(sqlite_config_serialized);     sqlite3_open([_dbpath utf8string], &_db);      return yes; }  - (bool)prepare:(const char *)sql {     if (! sqlite3_prepare_v2(_db, sql, -1, &_statement, null) == sqlite_ok) {         nslog(@"error whilst preparing query: %s", sqlite3_errmsg(_db));         sqlite3_finalize(_statement);         return no;     }      return yes; }  - (bool)step {     if (sqlite3_step(_statement) == sqlite_row) {         return yes;     }      return no; }  - (void)finalise {     sqlite3_finalize(_statement); }  @end


Comments

Post a Comment

Popular posts from this blog

ruby - Trying to change last to "x"s to 23 -

-
i have been playing around irb , have string looks this: irb(main):072:0> puts ["[\"4354 5432 5432 xxxxx\", \"6547 6547 8543 xxxxx\", \"2344 6543 6674 xxxxx\", \"2346 6236 7543 xxxxx\", \"1273 5585 5587 xxxxx\"]"] => nil irb(main):073:0> what want gsub last 2 "x" s of each 17 digit combination, 23 . what i've tried far (i've been using rubular): a.gsub(/\d[x]/,"23") <= grabs "x" s i'm close a.gsub(/\w[x{2}]/,"23") <= grabs "x" s grabs two digits each combination. is there easier way i'm not understanding? a.gsub(/\d{4} \d{4} \d{4} xxx\kxx/, '23') \d{4} = 4 digits what \k drop matched far. can use don't replace entire number, still able validate have in desired format.
Read more

jquery - Clone last and append item to closest class -

-
this bare-bones code on page: <div class="list-container"> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> </div> <p><button class="add-list-item">add</button></p> <div class="list-container"> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> </div> <p><button class="add-list-item">add</button></p> <di
Read more

c - Unrecognised emulation mode: elf_i386 on MinGW32 -

-
i'm trying make kernel, , cannot link c output assembly. ld . i'm getting error: unrecognized emulation mode: elf_i386 i'm using windows 10 professional mingw32 , msys. code using: link.ld /* * link.ld */ output_format(elf32-i386) entry(start) sections { . = 0x100000; .text : { *(.text) } .data : { *(.data) } .bss : { *(.bss) } } kernel.c /* * kernel.c */ void kmain(void) { const char *str = "my first kernel"; char *vidptr = (char*)0xb8000; //video mem begins here. unsigned int = 0; unsigned int j = 0; /* loops clears screen * there 25 lines each of 80 columns; each element takes 2 bytes */ while(j < 80 * 25 * 2) { /* blank character */ vidptr[j] = ' '; /* attribute-byte - light grey on black screen */ vidptr[j+1] = 0x07; j = j + 2; } j = 0; /* loop writes string video memory */ while(str[j] != '\0') { /
Read more