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| 1 /* | |
| 2 ** 2001 September 16 | |
| 3 ** | |
| 4 ** The author disclaims copyright to this source code. In place of | |
| 5 ** a legal notice, here is a blessing: | |
| 6 ** | |
| 7 ** May you do good and not evil. | |
| 8 ** May you find forgiveness for yourself and forgive others. | |
| 9 ** May you share freely, never taking more than you give. | |
| 10 ** | |
| 11 ****************************************************************************** | |
| 12 ** | |
| 13 ** This header file (together with is companion C source-code file | |
| 14 ** "os.c") attempt to abstract the underlying operating system so that | |
| 15 ** the SQLite library will work on both POSIX and windows systems. | |
| 16 ** | |
| 17 ** This header file is #include-ed by sqliteInt.h and thus ends up | |
| 18 ** being included by every source file. | |
| 19 ** | |
| 20 ** $Id: os.h,v 1.108 2009/02/05 16:31:46 drh Exp $ | |
| 21 */ | |
| 22 #ifndef _SQLITE_OS_H_ | |
| 23 #define _SQLITE_OS_H_ | |
| 24 | |
| 25 /* | |
| 26 ** Figure out if we are dealing with Unix, Windows, or some other | |
| 27 ** operating system. After the following block of preprocess macros, | |
| 28 ** all of SQLITE_OS_UNIX, SQLITE_OS_WIN, SQLITE_OS_OS2, and SQLITE_OS_OTHER | |
| 29 ** will defined to either 1 or 0. One of the four will be 1. The other | |
| 30 ** three will be 0. | |
| 31 */ | |
| 32 #ifdef OS_SYMBIAN | |
| 33 # define SQLITE_OS_SYMBIAN 1 | |
| 34 # define SQLITE_OS_OTHER 1 | |
| 35 #endif | |
| 36 #if defined(SQLITE_OS_OTHER) | |
| 37 # if SQLITE_OS_OTHER==1 | |
| 38 # undef SQLITE_OS_UNIX | |
| 39 # define SQLITE_OS_UNIX 0 | |
| 40 # undef SQLITE_OS_WIN | |
| 41 # define SQLITE_OS_WIN 0 | |
| 42 # undef SQLITE_OS_OS2 | |
| 43 # define SQLITE_OS_OS2 0 | |
| 44 # else | |
| 45 # undef SQLITE_OS_OTHER | |
| 46 # endif | |
| 47 #endif | |
| 48 #if !defined(SQLITE_OS_UNIX) && !defined(SQLITE_OS_OTHER) | |
| 49 # define SQLITE_OS_OTHER 0 | |
| 50 # ifndef SQLITE_OS_WIN | |
| 51 # if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MIN
GW32__) || defined(__BORLANDC__) | |
| 52 # define SQLITE_OS_WIN 1 | |
| 53 # define SQLITE_OS_UNIX 0 | |
| 54 # define SQLITE_OS_OS2 0 | |
| 55 # elif defined(__EMX__) || defined(_OS2) || defined(OS2) || defined(_OS2_) ||
defined(__OS2__) | |
| 56 # define SQLITE_OS_WIN 0 | |
| 57 # define SQLITE_OS_UNIX 0 | |
| 58 # define SQLITE_OS_OS2 1 | |
| 59 # else | |
| 60 # define SQLITE_OS_WIN 0 | |
| 61 # define SQLITE_OS_UNIX 1 | |
| 62 # define SQLITE_OS_OS2 0 | |
| 63 # endif | |
| 64 # else | |
| 65 # define SQLITE_OS_UNIX 0 | |
| 66 # define SQLITE_OS_OS2 0 | |
| 67 # endif | |
| 68 #else | |
| 69 # ifndef SQLITE_OS_WIN | |
| 70 # define SQLITE_OS_WIN 0 | |
| 71 # endif | |
| 72 #endif | |
| 73 | |
| 74 /* | |
| 75 ** Determine if we are dealing with WindowsCE - which has a much | |
| 76 ** reduced API. | |
| 77 */ | |
| 78 #if defined(_WIN32_WCE) | |
| 79 # define SQLITE_OS_WINCE 1 | |
| 80 #else | |
| 81 # define SQLITE_OS_WINCE 0 | |
| 82 #endif | |
| 83 | |
| 84 | |
| 85 /* | |
| 86 ** Define the maximum size of a temporary filename | |
| 87 */ | |
| 88 #if SQLITE_OS_WIN | |
| 89 # include <windows.h> | |
| 90 # define SQLITE_TEMPNAME_SIZE (MAX_PATH+50) | |
| 91 #elif SQLITE_OS_OS2 | |
| 92 # if (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3) && defined(OS2_HIGH_
MEMORY) | |
| 93 # include <os2safe.h> /* has to be included before os2.h for linking to work */ | |
| 94 # endif | |
| 95 # define INCL_DOSDATETIME | |
| 96 # define INCL_DOSFILEMGR | |
| 97 # define INCL_DOSERRORS | |
| 98 # define INCL_DOSMISC | |
| 99 # define INCL_DOSPROCESS | |
| 100 # define INCL_DOSMODULEMGR | |
| 101 # define INCL_DOSSEMAPHORES | |
| 102 # include <os2.h> | |
| 103 # include <uconv.h> | |
| 104 # define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP) | |
| 105 #else | |
| 106 # define SQLITE_TEMPNAME_SIZE 200 | |
| 107 #endif | |
| 108 | |
| 109 /* If the SET_FULLSYNC macro is not defined above, then make it | |
| 110 ** a no-op | |
| 111 */ | |
| 112 #ifndef SET_FULLSYNC | |
| 113 # define SET_FULLSYNC(x,y) | |
| 114 #endif | |
| 115 | |
| 116 /* | |
| 117 ** The default size of a disk sector | |
| 118 */ | |
| 119 #ifndef SQLITE_DEFAULT_SECTOR_SIZE | |
| 120 # define SQLITE_DEFAULT_SECTOR_SIZE 512 | |
| 121 #endif | |
| 122 | |
| 123 /* | |
| 124 ** Temporary files are named starting with this prefix followed by 16 random | |
| 125 ** alphanumeric characters, and no file extension. They are stored in the | |
| 126 ** OS's standard temporary file directory, and are deleted prior to exit. | |
| 127 ** If sqlite is being embedded in another program, you may wish to change the | |
| 128 ** prefix to reflect your program's name, so that if your program exits | |
| 129 ** prematurely, old temporary files can be easily identified. This can be done | |
| 130 ** using -DSQLITE_TEMP_FILE_PREFIX=myprefix_ on the compiler command line. | |
| 131 ** | |
| 132 ** 2006-10-31: The default prefix used to be "sqlite_". But then | |
| 133 ** Mcafee started using SQLite in their anti-virus product and it | |
| 134 ** started putting files with the "sqlite" name in the c:/temp folder. | |
| 135 ** This annoyed many windows users. Those users would then do a | |
| 136 ** Google search for "sqlite", find the telephone numbers of the | |
| 137 ** developers and call to wake them up at night and complain. | |
| 138 ** For this reason, the default name prefix is changed to be "sqlite" | |
| 139 ** spelled backwards. So the temp files are still identified, but | |
| 140 ** anybody smart enough to figure out the code is also likely smart | |
| 141 ** enough to know that calling the developer will not help get rid | |
| 142 ** of the file. | |
| 143 */ | |
| 144 #ifndef SQLITE_TEMP_FILE_PREFIX | |
| 145 # define SQLITE_TEMP_FILE_PREFIX "etilqs_" | |
| 146 #endif | |
| 147 | |
| 148 /* | |
| 149 ** The following values may be passed as the second argument to | |
| 150 ** sqlite3OsLock(). The various locks exhibit the following semantics: | |
| 151 ** | |
| 152 ** SHARED: Any number of processes may hold a SHARED lock simultaneously. | |
| 153 ** RESERVED: A single process may hold a RESERVED lock on a file at | |
| 154 ** any time. Other processes may hold and obtain new SHARED locks. | |
| 155 ** PENDING: A single process may hold a PENDING lock on a file at | |
| 156 ** any one time. Existing SHARED locks may persist, but no new | |
| 157 ** SHARED locks may be obtained by other processes. | |
| 158 ** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks. | |
| 159 ** | |
| 160 ** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a | |
| 161 ** process that requests an EXCLUSIVE lock may actually obtain a PENDING | |
| 162 ** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to | |
| 163 ** sqlite3OsLock(). | |
| 164 */ | |
| 165 #define NO_LOCK 0 | |
| 166 #define SHARED_LOCK 1 | |
| 167 #define RESERVED_LOCK 2 | |
| 168 #define PENDING_LOCK 3 | |
| 169 #define EXCLUSIVE_LOCK 4 | |
| 170 | |
| 171 /* | |
| 172 ** File Locking Notes: (Mostly about windows but also some info for Unix) | |
| 173 ** | |
| 174 ** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because | |
| 175 ** those functions are not available. So we use only LockFile() and | |
| 176 ** UnlockFile(). | |
| 177 ** | |
| 178 ** LockFile() prevents not just writing but also reading by other processes. | |
| 179 ** A SHARED_LOCK is obtained by locking a single randomly-chosen | |
| 180 ** byte out of a specific range of bytes. The lock byte is obtained at | |
| 181 ** random so two separate readers can probably access the file at the | |
| 182 ** same time, unless they are unlucky and choose the same lock byte. | |
| 183 ** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range. | |
| 184 ** There can only be one writer. A RESERVED_LOCK is obtained by locking | |
| 185 ** a single byte of the file that is designated as the reserved lock byte. | |
| 186 ** A PENDING_LOCK is obtained by locking a designated byte different from | |
| 187 ** the RESERVED_LOCK byte. | |
| 188 ** | |
| 189 ** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available, | |
| 190 ** which means we can use reader/writer locks. When reader/writer locks | |
| 191 ** are used, the lock is placed on the same range of bytes that is used | |
| 192 ** for probabilistic locking in Win95/98/ME. Hence, the locking scheme | |
| 193 ** will support two or more Win95 readers or two or more WinNT readers. | |
| 194 ** But a single Win95 reader will lock out all WinNT readers and a single | |
| 195 ** WinNT reader will lock out all other Win95 readers. | |
| 196 ** | |
| 197 ** The following #defines specify the range of bytes used for locking. | |
| 198 ** SHARED_SIZE is the number of bytes available in the pool from which | |
| 199 ** a random byte is selected for a shared lock. The pool of bytes for | |
| 200 ** shared locks begins at SHARED_FIRST. | |
| 201 ** | |
| 202 ** The same locking strategy and | |
| 203 ** byte ranges are used for Unix. This leaves open the possiblity of having | |
| 204 ** clients on win95, winNT, and unix all talking to the same shared file | |
| 205 ** and all locking correctly. To do so would require that samba (or whatever | |
| 206 ** tool is being used for file sharing) implements locks correctly between | |
| 207 ** windows and unix. I'm guessing that isn't likely to happen, but by | |
| 208 ** using the same locking range we are at least open to the possibility. | |
| 209 ** | |
| 210 ** Locking in windows is manditory. For this reason, we cannot store | |
| 211 ** actual data in the bytes used for locking. The pager never allocates | |
| 212 ** the pages involved in locking therefore. SHARED_SIZE is selected so | |
| 213 ** that all locks will fit on a single page even at the minimum page size. | |
| 214 ** PENDING_BYTE defines the beginning of the locks. By default PENDING_BYTE | |
| 215 ** is set high so that we don't have to allocate an unused page except | |
| 216 ** for very large databases. But one should test the page skipping logic | |
| 217 ** by setting PENDING_BYTE low and running the entire regression suite. | |
| 218 ** | |
| 219 ** Changing the value of PENDING_BYTE results in a subtly incompatible | |
| 220 ** file format. Depending on how it is changed, you might not notice | |
| 221 ** the incompatibility right away, even running a full regression test. | |
| 222 ** The default location of PENDING_BYTE is the first byte past the | |
| 223 ** 1GB boundary. | |
| 224 ** | |
| 225 */ | |
| 226 #define PENDING_BYTE sqlite3PendingByte | |
| 227 #define RESERVED_BYTE (PENDING_BYTE+1) | |
| 228 #define SHARED_FIRST (PENDING_BYTE+2) | |
| 229 #define SHARED_SIZE 510 | |
| 230 | |
| 231 /* | |
| 232 ** Wrapper around OS specific sqlite3_os_init() function. | |
| 233 */ | |
| 234 int sqlite3OsInit(void); | |
| 235 | |
| 236 /* | |
| 237 ** Functions for accessing sqlite3_file methods | |
| 238 */ | |
| 239 int sqlite3OsClose(sqlite3_file*); | |
| 240 int sqlite3OsRead(sqlite3_file*, void*, int amt, i64 offset); | |
| 241 int sqlite3OsWrite(sqlite3_file*, const void*, int amt, i64 offset); | |
| 242 int sqlite3OsTruncate(sqlite3_file*, i64 size); | |
| 243 int sqlite3OsSync(sqlite3_file*, int); | |
| 244 int sqlite3OsFileSize(sqlite3_file*, i64 *pSize); | |
| 245 int sqlite3OsLock(sqlite3_file*, int); | |
| 246 int sqlite3OsUnlock(sqlite3_file*, int); | |
| 247 int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut); | |
| 248 int sqlite3OsFileControl(sqlite3_file*,int,void*); | |
| 249 #define SQLITE_FCNTL_DB_UNCHANGED 0xca093fa0 | |
| 250 int sqlite3OsSectorSize(sqlite3_file *id); | |
| 251 int sqlite3OsDeviceCharacteristics(sqlite3_file *id); | |
| 252 | |
| 253 /* | |
| 254 ** Functions for accessing sqlite3_vfs methods | |
| 255 */ | |
| 256 int sqlite3OsOpen(sqlite3_vfs *, const char *, sqlite3_file*, int, int *); | |
| 257 int sqlite3OsDelete(sqlite3_vfs *, const char *, int); | |
| 258 int sqlite3OsAccess(sqlite3_vfs *, const char *, int, int *pResOut); | |
| 259 int sqlite3OsFullPathname(sqlite3_vfs *, const char *, int, char *); | |
| 260 #ifndef SQLITE_OMIT_LOAD_EXTENSION | |
| 261 void *sqlite3OsDlOpen(sqlite3_vfs *, const char *); | |
| 262 void sqlite3OsDlError(sqlite3_vfs *, int, char *); | |
| 263 void (*sqlite3OsDlSym(sqlite3_vfs *, void *, const char *))(void); | |
| 264 void sqlite3OsDlClose(sqlite3_vfs *, void *); | |
| 265 #endif /* SQLITE_OMIT_LOAD_EXTENSION */ | |
| 266 int sqlite3OsRandomness(sqlite3_vfs *, int, char *); | |
| 267 int sqlite3OsSleep(sqlite3_vfs *, int); | |
| 268 int sqlite3OsCurrentTime(sqlite3_vfs *, double*); | |
| 269 | |
| 270 /* | |
| 271 ** Convenience functions for opening and closing files using | |
| 272 ** sqlite3_malloc() to obtain space for the file-handle structure. | |
| 273 */ | |
| 274 int sqlite3OsOpenMalloc(sqlite3_vfs *, const char *, sqlite3_file **, int,int*); | |
| 275 int sqlite3OsCloseFree(sqlite3_file *); | |
| 276 | |
| 277 #endif /* _SQLITE_OS_H_ */ | |
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Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/