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bazarr/libs/playhouse/_sqlite_ext.pyx

1580 lines
49 KiB

import hashlib
import zlib
cimport cython
from cpython cimport datetime
from cpython.bytes cimport PyBytes_AsStringAndSize
from cpython.bytes cimport PyBytes_Check
from cpython.bytes cimport PyBytes_FromStringAndSize
from cpython.bytes cimport PyBytes_AS_STRING
from cpython.object cimport PyObject
from cpython.ref cimport Py_INCREF, Py_DECREF
from cpython.unicode cimport PyUnicode_AsUTF8String
from cpython.unicode cimport PyUnicode_Check
from cpython.unicode cimport PyUnicode_DecodeUTF8
from cpython.version cimport PY_MAJOR_VERSION
from libc.float cimport DBL_MAX
from libc.math cimport ceil, log, sqrt
from libc.math cimport pow as cpow
#from libc.stdint cimport ssize_t
from libc.stdint cimport uint8_t
from libc.stdint cimport uint32_t
from libc.stdlib cimport calloc, free, malloc, rand
from libc.string cimport memcpy, memset, strlen
from peewee import InterfaceError
from peewee import Node
from peewee import OperationalError
from peewee import sqlite3 as pysqlite
import traceback
cdef struct sqlite3_index_constraint:
int iColumn # Column constrained, -1 for rowid.
unsigned char op # Constraint operator.
unsigned char usable # True if this constraint is usable.
int iTermOffset # Used internally - xBestIndex should ignore.
cdef struct sqlite3_index_orderby:
int iColumn
unsigned char desc
cdef struct sqlite3_index_constraint_usage:
int argvIndex # if > 0, constraint is part of argv to xFilter.
unsigned char omit
cdef extern from "sqlite3.h" nogil:
ctypedef struct sqlite3:
int busyTimeout
ctypedef struct sqlite3_backup
ctypedef struct sqlite3_blob
ctypedef struct sqlite3_context
ctypedef struct sqlite3_value
ctypedef long long sqlite3_int64
ctypedef unsigned long long sqlite_uint64
# Virtual tables.
ctypedef struct sqlite3_module # Forward reference.
ctypedef struct sqlite3_vtab:
const sqlite3_module *pModule
int nRef
char *zErrMsg
ctypedef struct sqlite3_vtab_cursor:
sqlite3_vtab *pVtab
ctypedef struct sqlite3_index_info:
int nConstraint
sqlite3_index_constraint *aConstraint
int nOrderBy
sqlite3_index_orderby *aOrderBy
sqlite3_index_constraint_usage *aConstraintUsage
int idxNum
char *idxStr
int needToFreeIdxStr
int orderByConsumed
double estimatedCost
sqlite3_int64 estimatedRows
int idxFlags
ctypedef struct sqlite3_module:
int iVersion
int (*xCreate)(sqlite3*, void *pAux, int argc, const char *const*argv,
sqlite3_vtab **ppVTab, char**)
int (*xConnect)(sqlite3*, void *pAux, int argc, const char *const*argv,
sqlite3_vtab **ppVTab, char**)
int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*)
int (*xDisconnect)(sqlite3_vtab *pVTab)
int (*xDestroy)(sqlite3_vtab *pVTab)
int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor)
int (*xClose)(sqlite3_vtab_cursor*)
int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
int argc, sqlite3_value **argv)
int (*xNext)(sqlite3_vtab_cursor*)
int (*xEof)(sqlite3_vtab_cursor*)
int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context *, int)
int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid)
int (*xUpdate)(sqlite3_vtab *pVTab, int, sqlite3_value **,
sqlite3_int64 **)
int (*xBegin)(sqlite3_vtab *pVTab)
int (*xSync)(sqlite3_vtab *pVTab)
int (*xCommit)(sqlite3_vtab *pVTab)
int (*xRollback)(sqlite3_vtab *pVTab)
int (*xFindFunction)(sqlite3_vtab *pVTab, int nArg, const char *zName,
void (**pxFunc)(sqlite3_context *, int,
sqlite3_value **),
void **ppArg)
int (*xRename)(sqlite3_vtab *pVTab, const char *zNew)
int (*xSavepoint)(sqlite3_vtab *pVTab, int)
int (*xRelease)(sqlite3_vtab *pVTab, int)
int (*xRollbackTo)(sqlite3_vtab *pVTab, int)
cdef int sqlite3_declare_vtab(sqlite3 *db, const char *zSQL)
cdef int sqlite3_create_module(sqlite3 *db, const char *zName,
const sqlite3_module *p, void *pClientData)
cdef const char sqlite3_version[]
# Encoding.
cdef int SQLITE_UTF8 = 1
# Return values.
cdef int SQLITE_OK = 0
cdef int SQLITE_ERROR = 1
cdef int SQLITE_INTERNAL = 2
cdef int SQLITE_PERM = 3
cdef int SQLITE_ABORT = 4
cdef int SQLITE_BUSY = 5
cdef int SQLITE_LOCKED = 6
cdef int SQLITE_NOMEM = 7
cdef int SQLITE_READONLY = 8
cdef int SQLITE_INTERRUPT = 9
cdef int SQLITE_DONE = 101
# Function type.
cdef int SQLITE_DETERMINISTIC = 0x800
# Types of filtering operations.
cdef int SQLITE_INDEX_CONSTRAINT_EQ = 2
cdef int SQLITE_INDEX_CONSTRAINT_GT = 4
cdef int SQLITE_INDEX_CONSTRAINT_LE = 8
cdef int SQLITE_INDEX_CONSTRAINT_LT = 16
cdef int SQLITE_INDEX_CONSTRAINT_GE = 32
cdef int SQLITE_INDEX_CONSTRAINT_MATCH = 64
# sqlite_value_type.
cdef int SQLITE_INTEGER = 1
cdef int SQLITE_FLOAT = 2
cdef int SQLITE3_TEXT = 3
cdef int SQLITE_TEXT = 3
cdef int SQLITE_BLOB = 4
cdef int SQLITE_NULL = 5
ctypedef void (*sqlite3_destructor_type)(void*)
# Converting from Sqlite -> Python.
cdef const void *sqlite3_value_blob(sqlite3_value*)
cdef int sqlite3_value_bytes(sqlite3_value*)
cdef double sqlite3_value_double(sqlite3_value*)
cdef int sqlite3_value_int(sqlite3_value*)
cdef sqlite3_int64 sqlite3_value_int64(sqlite3_value*)
cdef const unsigned char *sqlite3_value_text(sqlite3_value*)
cdef int sqlite3_value_type(sqlite3_value*)
cdef int sqlite3_value_numeric_type(sqlite3_value*)
# Converting from Python -> Sqlite.
cdef void sqlite3_result_blob(sqlite3_context*, const void *, int,
void(*)(void*))
cdef void sqlite3_result_double(sqlite3_context*, double)
cdef void sqlite3_result_error(sqlite3_context*, const char*, int)
cdef void sqlite3_result_error_toobig(sqlite3_context*)
cdef void sqlite3_result_error_nomem(sqlite3_context*)
cdef void sqlite3_result_error_code(sqlite3_context*, int)
cdef void sqlite3_result_int(sqlite3_context*, int)
cdef void sqlite3_result_int64(sqlite3_context*, sqlite3_int64)
cdef void sqlite3_result_null(sqlite3_context*)
cdef void sqlite3_result_text(sqlite3_context*, const char*, int,
void(*)(void*))
cdef void sqlite3_result_value(sqlite3_context*, sqlite3_value*)
# Memory management.
cdef void* sqlite3_malloc(int)
cdef void sqlite3_free(void *)
cdef int sqlite3_changes(sqlite3 *db)
cdef int sqlite3_get_autocommit(sqlite3 *db)
cdef sqlite3_int64 sqlite3_last_insert_rowid(sqlite3 *db)
cdef void *sqlite3_commit_hook(sqlite3 *, int(*)(void *), void *)
cdef void *sqlite3_rollback_hook(sqlite3 *, void(*)(void *), void *)
cdef void *sqlite3_update_hook(
sqlite3 *,
void(*)(void *, int, char *, char *, sqlite3_int64),
void *)
cdef int SQLITE_STATUS_MEMORY_USED = 0
cdef int SQLITE_STATUS_PAGECACHE_USED = 1
cdef int SQLITE_STATUS_PAGECACHE_OVERFLOW = 2
cdef int SQLITE_STATUS_SCRATCH_USED = 3
cdef int SQLITE_STATUS_SCRATCH_OVERFLOW = 4
cdef int SQLITE_STATUS_MALLOC_SIZE = 5
cdef int SQLITE_STATUS_PARSER_STACK = 6
cdef int SQLITE_STATUS_PAGECACHE_SIZE = 7
cdef int SQLITE_STATUS_SCRATCH_SIZE = 8
cdef int SQLITE_STATUS_MALLOC_COUNT = 9
cdef int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag)
cdef int SQLITE_DBSTATUS_LOOKASIDE_USED = 0
cdef int SQLITE_DBSTATUS_CACHE_USED = 1
cdef int SQLITE_DBSTATUS_SCHEMA_USED = 2
cdef int SQLITE_DBSTATUS_STMT_USED = 3
cdef int SQLITE_DBSTATUS_LOOKASIDE_HIT = 4
cdef int SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE = 5
cdef int SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL = 6
cdef int SQLITE_DBSTATUS_CACHE_HIT = 7
cdef int SQLITE_DBSTATUS_CACHE_MISS = 8
cdef int SQLITE_DBSTATUS_CACHE_WRITE = 9
cdef int SQLITE_DBSTATUS_DEFERRED_FKS = 10
#cdef int SQLITE_DBSTATUS_CACHE_USED_SHARED = 11
cdef int sqlite3_db_status(sqlite3 *, int op, int *pCur, int *pHigh, int reset)
cdef int SQLITE_DELETE = 9
cdef int SQLITE_INSERT = 18
cdef int SQLITE_UPDATE = 23
cdef int SQLITE_CONFIG_SINGLETHREAD = 1 # None
cdef int SQLITE_CONFIG_MULTITHREAD = 2 # None
cdef int SQLITE_CONFIG_SERIALIZED = 3 # None
cdef int SQLITE_CONFIG_SCRATCH = 6 # void *, int sz, int N
cdef int SQLITE_CONFIG_PAGECACHE = 7 # void *, int sz, int N
cdef int SQLITE_CONFIG_HEAP = 8 # void *, int nByte, int min
cdef int SQLITE_CONFIG_MEMSTATUS = 9 # boolean
cdef int SQLITE_CONFIG_LOOKASIDE = 13 # int, int
cdef int SQLITE_CONFIG_URI = 17 # int
cdef int SQLITE_CONFIG_MMAP_SIZE = 22 # sqlite3_int64, sqlite3_int64
cdef int SQLITE_CONFIG_STMTJRNL_SPILL = 26 # int nByte
cdef int SQLITE_DBCONFIG_MAINDBNAME = 1000 # const char*
cdef int SQLITE_DBCONFIG_LOOKASIDE = 1001 # void* int int
cdef int SQLITE_DBCONFIG_ENABLE_FKEY = 1002 # int int*
cdef int SQLITE_DBCONFIG_ENABLE_TRIGGER = 1003 # int int*
cdef int SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER = 1004 # int int*
cdef int SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION = 1005 # int int*
cdef int SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE = 1006 # int int*
cdef int SQLITE_DBCONFIG_ENABLE_QPSG = 1007 # int int*
cdef int sqlite3_config(int, ...)
cdef int sqlite3_db_config(sqlite3*, int op, ...)
# Misc.
cdef int sqlite3_busy_handler(sqlite3 *db, int(*)(void *, int), void *)
cdef int sqlite3_sleep(int ms)
cdef sqlite3_backup *sqlite3_backup_init(
sqlite3 *pDest,
const char *zDestName,
sqlite3 *pSource,
const char *zSourceName)
# Backup.
cdef int sqlite3_backup_step(sqlite3_backup *p, int nPage)
cdef int sqlite3_backup_finish(sqlite3_backup *p)
cdef int sqlite3_backup_remaining(sqlite3_backup *p)
cdef int sqlite3_backup_pagecount(sqlite3_backup *p)
# Error handling.
cdef int sqlite3_errcode(sqlite3 *db)
cdef int sqlite3_errstr(int)
cdef const char *sqlite3_errmsg(sqlite3 *db)
cdef char *sqlite3_mprintf(const char *, ...)
cdef int sqlite3_blob_open(
sqlite3*,
const char *zDb,
const char *zTable,
const char *zColumn,
sqlite3_int64 iRow,
int flags,
sqlite3_blob **ppBlob)
cdef int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64)
cdef int sqlite3_blob_close(sqlite3_blob *)
cdef int sqlite3_blob_bytes(sqlite3_blob *)
cdef int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset)
cdef int sqlite3_blob_write(sqlite3_blob *, const void *z, int n,
int iOffset)
cdef extern from "_pysqlite/connection.h":
ctypedef struct pysqlite_Connection:
sqlite3* db
double timeout
int initialized
cdef sqlite_to_python(int argc, sqlite3_value **params):
cdef:
int i
int vtype
list pyargs = []
for i in range(argc):
vtype = sqlite3_value_type(params[i])
if vtype == SQLITE_INTEGER:
pyval = sqlite3_value_int(params[i])
elif vtype == SQLITE_FLOAT:
pyval = sqlite3_value_double(params[i])
elif vtype == SQLITE_TEXT:
pyval = PyUnicode_DecodeUTF8(
<const char *>sqlite3_value_text(params[i]),
<Py_ssize_t>sqlite3_value_bytes(params[i]), NULL)
elif vtype == SQLITE_BLOB:
pyval = PyBytes_FromStringAndSize(
<const char *>sqlite3_value_blob(params[i]),
<Py_ssize_t>sqlite3_value_bytes(params[i]))
elif vtype == SQLITE_NULL:
pyval = None
else:
pyval = None
pyargs.append(pyval)
return pyargs
cdef python_to_sqlite(sqlite3_context *context, value):
if value is None:
sqlite3_result_null(context)
elif isinstance(value, (int, long)):
sqlite3_result_int64(context, <sqlite3_int64>value)
elif isinstance(value, float):
sqlite3_result_double(context, <double>value)
elif isinstance(value, unicode):
bval = PyUnicode_AsUTF8String(value)
sqlite3_result_text(
context,
<const char *>bval,
len(bval),
<sqlite3_destructor_type>-1)
elif isinstance(value, bytes):
if PY_MAJOR_VERSION > 2:
sqlite3_result_blob(
context,
<void *>(<char *>value),
len(value),
<sqlite3_destructor_type>-1)
else:
sqlite3_result_text(
context,
<const char *>value,
len(value),
<sqlite3_destructor_type>-1)
else:
sqlite3_result_error(
context,
encode('Unsupported type %s' % type(value)),
-1)
return SQLITE_ERROR
return SQLITE_OK
cdef int SQLITE_CONSTRAINT = 19 # Abort due to constraint violation.
USE_SQLITE_CONSTRAINT = sqlite3_version[:4] >= b'3.26'
# The peewee_vtab struct embeds the base sqlite3_vtab struct, and adds a field
# to store a reference to the Python implementation.
ctypedef struct peewee_vtab:
sqlite3_vtab base
void *table_func_cls
# Like peewee_vtab, the peewee_cursor embeds the base sqlite3_vtab_cursor and
# adds fields to store references to the current index, the Python
# implementation, the current rows' data, and a flag for whether the cursor has
# been exhausted.
ctypedef struct peewee_cursor:
sqlite3_vtab_cursor base
long long idx
void *table_func
void *row_data
bint stopped
# We define an xConnect function, but leave xCreate NULL so that the
# table-function can be called eponymously.
cdef int pwConnect(sqlite3 *db, void *pAux, int argc, const char *const*argv,
sqlite3_vtab **ppVtab, char **pzErr) with gil:
cdef:
int rc
object table_func_cls = <object>pAux
peewee_vtab *pNew = <peewee_vtab *>0
rc = sqlite3_declare_vtab(
db,
encode('CREATE TABLE x(%s);' %
table_func_cls.get_table_columns_declaration()))
if rc == SQLITE_OK:
pNew = <peewee_vtab *>sqlite3_malloc(sizeof(pNew[0]))
memset(<char *>pNew, 0, sizeof(pNew[0]))
ppVtab[0] = &(pNew.base)
pNew.table_func_cls = <void *>table_func_cls
Py_INCREF(table_func_cls)
return rc
cdef int pwDisconnect(sqlite3_vtab *pBase) with gil:
cdef:
peewee_vtab *pVtab = <peewee_vtab *>pBase
object table_func_cls = <object>(pVtab.table_func_cls)
Py_DECREF(table_func_cls)
sqlite3_free(pVtab)
return SQLITE_OK
# The xOpen method is used to initialize a cursor. In this method we
# instantiate the TableFunction class and zero out a new cursor for iteration.
cdef int pwOpen(sqlite3_vtab *pBase, sqlite3_vtab_cursor **ppCursor) with gil:
cdef:
peewee_vtab *pVtab = <peewee_vtab *>pBase
peewee_cursor *pCur = <peewee_cursor *>0
object table_func_cls = <object>pVtab.table_func_cls
pCur = <peewee_cursor *>sqlite3_malloc(sizeof(pCur[0]))
memset(<char *>pCur, 0, sizeof(pCur[0]))
ppCursor[0] = &(pCur.base)
pCur.idx = 0
try:
table_func = table_func_cls()
except:
if table_func_cls.print_tracebacks:
traceback.print_exc()
sqlite3_free(pCur)
return SQLITE_ERROR
Py_INCREF(table_func)
pCur.table_func = <void *>table_func
pCur.stopped = False
return SQLITE_OK
cdef int pwClose(sqlite3_vtab_cursor *pBase) with gil:
cdef:
peewee_cursor *pCur = <peewee_cursor *>pBase
object table_func = <object>pCur.table_func
Py_DECREF(table_func)
sqlite3_free(pCur)
return SQLITE_OK
# Iterate once, advancing the cursor's index and assigning the row data to the
# `row_data` field on the peewee_cursor struct.
cdef int pwNext(sqlite3_vtab_cursor *pBase) with gil:
cdef:
peewee_cursor *pCur = <peewee_cursor *>pBase
object table_func = <object>pCur.table_func
tuple result
if pCur.row_data:
Py_DECREF(<tuple>pCur.row_data)
pCur.row_data = NULL
try:
result = tuple(table_func.iterate(pCur.idx))
except StopIteration:
pCur.stopped = True
except:
if table_func.print_tracebacks:
traceback.print_exc()
return SQLITE_ERROR
else:
Py_INCREF(result)
pCur.row_data = <void *>result
pCur.idx += 1
pCur.stopped = False
return SQLITE_OK
# Return the requested column from the current row.
cdef int pwColumn(sqlite3_vtab_cursor *pBase, sqlite3_context *ctx,
int iCol) with gil:
cdef:
bytes bval
peewee_cursor *pCur = <peewee_cursor *>pBase
sqlite3_int64 x = 0
tuple row_data
if iCol == -1:
sqlite3_result_int64(ctx, <sqlite3_int64>pCur.idx)
return SQLITE_OK
if not pCur.row_data:
sqlite3_result_error(ctx, encode('no row data'), -1)
return SQLITE_ERROR
row_data = <tuple>pCur.row_data
return python_to_sqlite(ctx, row_data[iCol])
cdef int pwRowid(sqlite3_vtab_cursor *pBase, sqlite3_int64 *pRowid):
cdef:
peewee_cursor *pCur = <peewee_cursor *>pBase
pRowid[0] = <sqlite3_int64>pCur.idx
return SQLITE_OK
# Return a boolean indicating whether the cursor has been consumed.
cdef int pwEof(sqlite3_vtab_cursor *pBase):
cdef:
peewee_cursor *pCur = <peewee_cursor *>pBase
return 1 if pCur.stopped else 0
# The filter method is called on the first iteration. This method is where we
# get access to the parameters that the function was called with, and call the
# TableFunction's `initialize()` function.
cdef int pwFilter(sqlite3_vtab_cursor *pBase, int idxNum,
const char *idxStr, int argc, sqlite3_value **argv) with gil:
cdef:
peewee_cursor *pCur = <peewee_cursor *>pBase
object table_func = <object>pCur.table_func
dict query = {}
int idx
int value_type
tuple row_data
void *row_data_raw
if not idxStr or argc == 0 and len(table_func.params):
return SQLITE_ERROR
elif len(idxStr):
params = decode(idxStr).split(',')
else:
params = []
py_values = sqlite_to_python(argc, argv)
for idx, param in enumerate(params):
value = argv[idx]
if not value:
query[param] = None
else:
query[param] = py_values[idx]
try:
table_func.initialize(**query)
except:
if table_func.print_tracebacks:
traceback.print_exc()
return SQLITE_ERROR
pCur.stopped = False
try:
row_data = tuple(table_func.iterate(0))
except StopIteration:
pCur.stopped = True
except:
if table_func.print_tracebacks:
traceback.print_exc()
return SQLITE_ERROR
else:
Py_INCREF(row_data)
pCur.row_data = <void *>row_data
pCur.idx += 1
return SQLITE_OK
# SQLite will (in some cases, repeatedly) call the xBestIndex method to try and
# find the best query plan.
cdef int pwBestIndex(sqlite3_vtab *pBase, sqlite3_index_info *pIdxInfo) \
with gil:
cdef:
int i
int col_idx
int idxNum = 0, nArg = 0
peewee_vtab *pVtab = <peewee_vtab *>pBase
object table_func_cls = <object>pVtab.table_func_cls
sqlite3_index_constraint *pConstraint = <sqlite3_index_constraint *>0
list columns = []
char *idxStr
int nParams = len(table_func_cls.params)
for i in range(pIdxInfo.nConstraint):
pConstraint = <sqlite3_index_constraint *>pIdxInfo.aConstraint + i
if not pConstraint.usable:
continue
if pConstraint.op != SQLITE_INDEX_CONSTRAINT_EQ:
continue
col_idx = pConstraint.iColumn - table_func_cls._ncols
if col_idx >= 0:
columns.append(table_func_cls.params[col_idx])
nArg += 1
pIdxInfo.aConstraintUsage[i].argvIndex = nArg
pIdxInfo.aConstraintUsage[i].omit = 1
if nArg > 0 or nParams == 0:
if nArg == nParams:
# All parameters are present, this is ideal.
pIdxInfo.estimatedCost = <double>1
pIdxInfo.estimatedRows = 10
else:
# Penalize score based on number of missing params.
pIdxInfo.estimatedCost = <double>10000000000000 * <double>(nParams - nArg)
pIdxInfo.estimatedRows = 10 ** (nParams - nArg)
# Store a reference to the columns in the index info structure.
joinedCols = encode(','.join(columns))
pIdxInfo.idxStr = sqlite3_mprintf("%s", <char *>joinedCols)
pIdxInfo.needToFreeIdxStr = 1
elif USE_SQLITE_CONSTRAINT:
return SQLITE_CONSTRAINT
else:
pIdxInfo.estimatedCost = DBL_MAX
pIdxInfo.estimatedRows = 100000
return SQLITE_OK
cdef class _TableFunctionImpl(object):
cdef:
sqlite3_module module
object table_function
def __cinit__(self, table_function):
self.table_function = table_function
cdef create_module(self, pysqlite_Connection* sqlite_conn):
cdef:
bytes name = encode(self.table_function.name)
sqlite3 *db = sqlite_conn.db
int rc
# Populate the SQLite module struct members.
self.module.iVersion = 0
self.module.xCreate = NULL
self.module.xConnect = pwConnect
self.module.xBestIndex = pwBestIndex
self.module.xDisconnect = pwDisconnect
self.module.xDestroy = NULL
self.module.xOpen = pwOpen
self.module.xClose = pwClose
self.module.xFilter = pwFilter
self.module.xNext = pwNext
self.module.xEof = pwEof
self.module.xColumn = pwColumn
self.module.xRowid = pwRowid
self.module.xUpdate = NULL
self.module.xBegin = NULL
self.module.xSync = NULL
self.module.xCommit = NULL
self.module.xRollback = NULL
self.module.xFindFunction = NULL
self.module.xRename = NULL
# Create the SQLite virtual table.
rc = sqlite3_create_module(
db,
<const char *>name,
&self.module,
<void *>(self.table_function))
Py_INCREF(self)
return rc == SQLITE_OK
class TableFunction(object):
columns = None
params = None
name = None
print_tracebacks = True
_ncols = None
@classmethod
def register(cls, conn):
cdef _TableFunctionImpl impl = _TableFunctionImpl(cls)
impl.create_module(<pysqlite_Connection *>conn)
cls._ncols = len(cls.columns)
def initialize(self, **filters):
raise NotImplementedError
def iterate(self, idx):
raise NotImplementedError
@classmethod
def get_table_columns_declaration(cls):
cdef list accum = []
for column in cls.columns:
if isinstance(column, tuple):
if len(column) != 2:
raise ValueError('Column must be either a string or a '
'2-tuple of name, type')
accum.append('%s %s' % column)
else:
accum.append(column)
for param in cls.params:
accum.append('%s HIDDEN' % param)
return ', '.join(accum)
cdef inline bytes encode(key):
cdef bytes bkey
if PyUnicode_Check(key):
bkey = PyUnicode_AsUTF8String(key)
elif PyBytes_Check(key):
bkey = <bytes>key
elif key is None:
return None
else:
bkey = PyUnicode_AsUTF8String(str(key))
return bkey
cdef inline unicode decode(key):
cdef unicode ukey
if PyBytes_Check(key):
ukey = key.decode('utf-8')
elif PyUnicode_Check(key):
ukey = <unicode>key
elif key is None:
return None
else:
ukey = unicode(key)
return ukey
cdef double *get_weights(int ncol, tuple raw_weights):
cdef:
int argc = len(raw_weights)
int icol
double *weights = <double *>malloc(sizeof(double) * ncol)
for icol in range(ncol):
if argc == 0:
weights[icol] = 1.0
elif icol < argc:
weights[icol] = <double>raw_weights[icol]
else:
weights[icol] = 0.0
return weights
def peewee_rank(py_match_info, *raw_weights):
cdef:
unsigned int *match_info
unsigned int *phrase_info
bytes _match_info_buf = bytes(py_match_info)
char *match_info_buf = _match_info_buf
int nphrase, ncol, icol, iphrase, hits, global_hits
int P_O = 0, C_O = 1, X_O = 2
double score = 0.0, weight
double *weights
match_info = <unsigned int *>match_info_buf
nphrase = match_info[P_O]
ncol = match_info[C_O]
weights = get_weights(ncol, raw_weights)
# matchinfo X value corresponds to, for each phrase in the search query, a
# list of 3 values for each column in the search table.
# So if we have a two-phrase search query and three columns of data, the
# following would be the layout:
# p0 : c0=[0, 1, 2], c1=[3, 4, 5], c2=[6, 7, 8]
# p1 : c0=[9, 10, 11], c1=[12, 13, 14], c2=[15, 16, 17]
for iphrase in range(nphrase):
phrase_info = &match_info[X_O + iphrase * ncol * 3]
for icol in range(ncol):
weight = weights[icol]
if weight == 0:
continue
# The idea is that we count the number of times the phrase appears
# in this column of the current row, compared to how many times it
# appears in this column across all rows. The ratio of these values
# provides a rough way to score based on "high value" terms.
hits = phrase_info[3 * icol]
global_hits = phrase_info[3 * icol + 1]
if hits > 0:
score += weight * (<double>hits / <double>global_hits)
free(weights)
return -1 * score
def peewee_lucene(py_match_info, *raw_weights):
# Usage: peewee_lucene(matchinfo(table, 'pcnalx'), 1)
cdef:
unsigned int *match_info
bytes _match_info_buf = bytes(py_match_info)
char *match_info_buf = _match_info_buf
int nphrase, ncol
double total_docs, term_frequency
double doc_length, docs_with_term, avg_length
double idf, weight, rhs, denom
double *weights
int P_O = 0, C_O = 1, N_O = 2, L_O, X_O
int iphrase, icol, x
double score = 0.0
match_info = <unsigned int *>match_info_buf
nphrase = match_info[P_O]
ncol = match_info[C_O]
total_docs = match_info[N_O]
L_O = 3 + ncol
X_O = L_O + ncol
weights = get_weights(ncol, raw_weights)
for iphrase in range(nphrase):
for icol in range(ncol):
weight = weights[icol]
if weight == 0:
continue
doc_length = match_info[L_O + icol]
x = X_O + (3 * (icol + iphrase * ncol))
term_frequency = match_info[x] # f(qi)
docs_with_term = match_info[x + 2] or 1. # n(qi)
idf = log(total_docs / (docs_with_term + 1.))
tf = sqrt(term_frequency)
fieldNorms = 1.0 / sqrt(doc_length)
score += (idf * tf * fieldNorms)
free(weights)
return -1 * score
def peewee_bm25(py_match_info, *raw_weights):
# Usage: peewee_bm25(matchinfo(table, 'pcnalx'), 1)
# where the second parameter is the index of the column and
# the 3rd and 4th specify k and b.
cdef:
unsigned int *match_info
bytes _match_info_buf = bytes(py_match_info)
char *match_info_buf = _match_info_buf
int nphrase, ncol
double B = 0.75, K = 1.2
double total_docs, term_frequency
double doc_length, docs_with_term, avg_length
double idf, weight, ratio, num, b_part, denom, pc_score
double *weights
int P_O = 0, C_O = 1, N_O = 2, A_O = 3, L_O, X_O
int iphrase, icol, x
double score = 0.0
match_info = <unsigned int *>match_info_buf
# PCNALX = matchinfo format.
# P = 1 = phrase count within query.
# C = 1 = searchable columns in table.
# N = 1 = total rows in table.
# A = c = for each column, avg number of tokens
# L = c = for each column, length of current row (in tokens)
# X = 3 * c * p = for each phrase and table column,
# * phrase count within column for current row.
# * phrase count within column for all rows.
# * total rows for which column contains phrase.
nphrase = match_info[P_O] # n
ncol = match_info[C_O]
total_docs = match_info[N_O] # N
L_O = A_O + ncol
X_O = L_O + ncol
weights = get_weights(ncol, raw_weights)
for iphrase in range(nphrase):
for icol in range(ncol):
weight = weights[icol]
if weight == 0:
continue
x = X_O + (3 * (icol + iphrase * ncol))
term_frequency = match_info[x] # f(qi, D)
docs_with_term = match_info[x + 2] # n(qi)
# log( (N - n(qi) + 0.5) / (n(qi) + 0.5) )
idf = log(
(total_docs - docs_with_term + 0.5) /
(docs_with_term + 0.5))
if idf <= 0.0:
idf = 1e-6
doc_length = match_info[L_O + icol] # |D|
avg_length = match_info[A_O + icol] # avgdl
if avg_length == 0:
avg_length = 1
ratio = doc_length / avg_length
num = term_frequency * (K + 1)
b_part = 1 - B + (B * ratio)
denom = term_frequency + (K * b_part)
pc_score = idf * (num / denom)
score += (pc_score * weight)
free(weights)
return -1 * score
def peewee_bm25f(py_match_info, *raw_weights):
# Usage: peewee_bm25f(matchinfo(table, 'pcnalx'), 1)
# where the second parameter is the index of the column and
# the 3rd and 4th specify k and b.
cdef:
unsigned int *match_info
bytes _match_info_buf = bytes(py_match_info)
char *match_info_buf = _match_info_buf
int nphrase, ncol
double B = 0.75, K = 1.2, epsilon
double total_docs, term_frequency, docs_with_term
double doc_length = 0.0, avg_length = 0.0
double idf, weight, ratio, num, b_part, denom, pc_score
double *weights
int P_O = 0, C_O = 1, N_O = 2, A_O = 3, L_O, X_O
int iphrase, icol, x
double score = 0.0
match_info = <unsigned int *>match_info_buf
nphrase = match_info[P_O] # n
ncol = match_info[C_O]
total_docs = match_info[N_O] # N
L_O = A_O + ncol
X_O = L_O + ncol
for icol in range(ncol):
avg_length += match_info[A_O + icol]
doc_length += match_info[L_O + icol]
epsilon = 1.0 / (total_docs * avg_length)
if avg_length == 0:
avg_length = 1
ratio = doc_length / avg_length
weights = get_weights(ncol, raw_weights)
for iphrase in range(nphrase):
for icol in range(ncol):
weight = weights[icol]
if weight == 0:
continue
x = X_O + (3 * (icol + iphrase * ncol))
term_frequency = match_info[x] # f(qi, D)
docs_with_term = match_info[x + 2] # n(qi)
# log( (N - n(qi) + 0.5) / (n(qi) + 0.5) )
idf = log(
(total_docs - docs_with_term + 0.5) /
(docs_with_term + 0.5))
idf = epsilon if idf <= 0 else idf
num = term_frequency * (K + 1)
b_part = 1 - B + (B * ratio)
denom = term_frequency + (K * b_part)
pc_score = idf * ((num / denom) + 1.)
score += (pc_score * weight)
free(weights)
return -1 * score
cdef uint32_t murmurhash2(const unsigned char *key, ssize_t nlen,
uint32_t seed):
cdef:
uint32_t m = 0x5bd1e995
int r = 24
const unsigned char *data = key
uint32_t h = seed ^ nlen
uint32_t k
while nlen >= 4:
k = <uint32_t>((<uint32_t *>data)[0])
k *= m
k = k ^ (k >> r)
k *= m
h *= m
h = h ^ k
data += 4
nlen -= 4
if nlen == 3:
h = h ^ (data[2] << 16)
if nlen >= 2:
h = h ^ (data[1] << 8)
if nlen >= 1:
h = h ^ (data[0])
h *= m
h = h ^ (h >> 13)
h *= m
h = h ^ (h >> 15)
return h
def peewee_murmurhash(key, seed=None):
if key is None:
return
cdef:
bytes bkey = encode(key)
int nseed = seed or 0
if key:
return murmurhash2(<unsigned char *>bkey, len(bkey), nseed)
return 0
def make_hash(hash_impl):
def inner(*items):
state = hash_impl()
for item in items:
state.update(encode(item))
return state.hexdigest()
return inner
peewee_md5 = make_hash(hashlib.md5)
peewee_sha1 = make_hash(hashlib.sha1)
peewee_sha256 = make_hash(hashlib.sha256)
def _register_functions(database, pairs):
for func, name in pairs:
database.register_function(func, name)
def register_hash_functions(database):
_register_functions(database, (
(peewee_murmurhash, 'murmurhash'),
(peewee_md5, 'md5'),
(peewee_sha1, 'sha1'),
(peewee_sha256, 'sha256'),
(zlib.adler32, 'adler32'),
(zlib.crc32, 'crc32')))
def register_rank_functions(database):
_register_functions(database, (
(peewee_bm25, 'fts_bm25'),
(peewee_bm25f, 'fts_bm25f'),
(peewee_lucene, 'fts_lucene'),
(peewee_rank, 'fts_rank')))
ctypedef struct bf_t:
void *bits
size_t size
cdef int seeds[10]
seeds[:] = [0, 1337, 37, 0xabcd, 0xdead, 0xface, 97, 0xed11, 0xcad9, 0x827b]
cdef bf_t *bf_create(size_t size):
cdef bf_t *bf = <bf_t *>calloc(1, sizeof(bf_t))
bf.size = size
bf.bits = calloc(1, size)
return bf
@cython.cdivision(True)
cdef uint32_t bf_bitindex(bf_t *bf, unsigned char *key, size_t klen, int seed):
cdef:
uint32_t h = murmurhash2(key, klen, seed)
return h % (bf.size * 8)
@cython.cdivision(True)
cdef bf_add(bf_t *bf, unsigned char *key):
cdef:
uint8_t *bits = <uint8_t *>(bf.bits)
uint32_t h
int pos, seed
size_t keylen = strlen(<const char *>key)
for seed in seeds:
h = bf_bitindex(bf, key, keylen, seed)
pos = h / 8
bits[pos] = bits[pos] | (1 << (h % 8))
@cython.cdivision(True)
cdef int bf_contains(bf_t *bf, unsigned char *key):
cdef:
uint8_t *bits = <uint8_t *>(bf.bits)
uint32_t h
int pos, seed
size_t keylen = strlen(<const char *>key)
for seed in seeds:
h = bf_bitindex(bf, key, keylen, seed)
pos = h / 8
if not (bits[pos] & (1 << (h % 8))):
return 0
return 1
cdef bf_free(bf_t *bf):
free(bf.bits)
free(bf)
cdef class BloomFilter(object):
cdef:
bf_t *bf
def __init__(self, size=1024 * 32):
self.bf = bf_create(<size_t>size)
def __dealloc__(self):
if self.bf:
bf_free(self.bf)
def __len__(self):
return self.bf.size
def add(self, *keys):
cdef bytes bkey
for key in keys:
bkey = encode(key)
bf_add(self.bf, <unsigned char *>bkey)
def __contains__(self, key):
cdef bytes bkey = encode(key)
return bf_contains(self.bf, <unsigned char *>bkey)
def to_buffer(self):
# We have to do this so that embedded NULL bytes are preserved.
cdef bytes buf = PyBytes_FromStringAndSize(<char *>(self.bf.bits),
self.bf.size)
# Similarly we wrap in a buffer object so pysqlite preserves the
# embedded NULL bytes.
return buf
@classmethod
def from_buffer(cls, data):
cdef:
char *buf
Py_ssize_t buflen
BloomFilter bloom
PyBytes_AsStringAndSize(data, &buf, &buflen)
bloom = BloomFilter(buflen)
memcpy(bloom.bf.bits, <void *>buf, buflen)
return bloom
@classmethod
def calculate_size(cls, double n, double p):
cdef double m = ceil((n * log(p)) / log(1.0 / (pow(2.0, log(2.0)))))
return m
cdef class BloomFilterAggregate(object):
cdef:
BloomFilter bf
def __init__(self):
self.bf = None
def step(self, value, size=None):
if not self.bf:
size = size or 1024
self.bf = BloomFilter(size)
self.bf.add(value)
def finalize(self):
if not self.bf:
return None
return pysqlite.Binary(self.bf.to_buffer())
def peewee_bloomfilter_contains(key, data):
cdef:
bf_t bf
bytes bkey
bytes bdata = bytes(data)
unsigned char *cdata = <unsigned char *>bdata
bf.size = len(data)
bf.bits = <void *>cdata
bkey = encode(key)
return bf_contains(&bf, <unsigned char *>bkey)
def peewee_bloomfilter_calculate_size(n_items, error_p):
return BloomFilter.calculate_size(n_items, error_p)
def register_bloomfilter(database):
database.register_aggregate(BloomFilterAggregate, 'bloomfilter')
database.register_function(peewee_bloomfilter_contains,
'bloomfilter_contains')
database.register_function(peewee_bloomfilter_calculate_size,
'bloomfilter_calculate_size')
cdef inline int _check_connection(pysqlite_Connection *conn) except -1:
"""
Check that the underlying SQLite database connection is usable. Raises an
InterfaceError if the connection is either uninitialized or closed.
"""
if not conn.db:
raise InterfaceError('Cannot operate on closed database.')
return 1
class ZeroBlob(Node):
def __init__(self, length):
if not isinstance(length, int) or length < 0:
raise ValueError('Length must be a positive integer.')
self.length = length
def __sql__(self, ctx):
return ctx.literal('zeroblob(%s)' % self.length)
cdef class Blob(object) # Forward declaration.
cdef inline int _check_blob_closed(Blob blob) except -1:
if not blob.pBlob:
raise InterfaceError('Cannot operate on closed blob.')
return 1
cdef class Blob(object):
cdef:
int offset
pysqlite_Connection *conn
sqlite3_blob *pBlob
def __init__(self, database, table, column, rowid,
read_only=False):
cdef:
bytes btable = encode(table)
bytes bcolumn = encode(column)
int flags = 0 if read_only else 1
int rc
sqlite3_blob *blob
self.conn = <pysqlite_Connection *>(database._state.conn)
_check_connection(self.conn)
rc = sqlite3_blob_open(
self.conn.db,
'main',
<char *>btable,
<char *>bcolumn,
<long long>rowid,
flags,
&blob)
if rc != SQLITE_OK:
raise OperationalError('Unable to open blob.')
if not blob:
raise MemoryError('Unable to allocate blob.')
self.pBlob = blob
self.offset = 0
cdef _close(self):
if self.pBlob:
sqlite3_blob_close(self.pBlob)
self.pBlob = <sqlite3_blob *>0
def __dealloc__(self):
self._close()
def __len__(self):
_check_blob_closed(self)
return sqlite3_blob_bytes(self.pBlob)
def read(self, n=None):
cdef:
bytes pybuf
int length = -1
int size
char *buf
if n is not None:
length = n
_check_blob_closed(self)
size = sqlite3_blob_bytes(self.pBlob)
if self.offset == size or length == 0:
return b''
if length < 0:
length = size - self.offset
if self.offset + length > size:
length = size - self.offset
pybuf = PyBytes_FromStringAndSize(NULL, length)
buf = PyBytes_AS_STRING(pybuf)
if sqlite3_blob_read(self.pBlob, buf, length, self.offset):
self._close()
raise OperationalError('Error reading from blob.')
self.offset += length
return bytes(pybuf)
def seek(self, offset, frame_of_reference=0):
cdef int size
_check_blob_closed(self)
size = sqlite3_blob_bytes(self.pBlob)
if frame_of_reference == 0:
if offset < 0 or offset > size:
raise ValueError('seek() offset outside of valid range.')
self.offset = offset
elif frame_of_reference == 1:
if self.offset + offset < 0 or self.offset + offset > size:
raise ValueError('seek() offset outside of valid range.')
self.offset += offset
elif frame_of_reference == 2:
if size + offset < 0 or size + offset > size:
raise ValueError('seek() offset outside of valid range.')
self.offset = size + offset
else:
raise ValueError('seek() frame of reference must be 0, 1 or 2.')
def tell(self):
_check_blob_closed(self)
return self.offset
def write(self, bytes data):
cdef:
char *buf
int size
Py_ssize_t buflen
_check_blob_closed(self)
size = sqlite3_blob_bytes(self.pBlob)
PyBytes_AsStringAndSize(data, &buf, &buflen)
if (<int>(buflen + self.offset)) < self.offset:
raise ValueError('Data is too large (integer wrap)')
if (<int>(buflen + self.offset)) > size:
raise ValueError('Data would go beyond end of blob')
if sqlite3_blob_write(self.pBlob, buf, buflen, self.offset):
raise OperationalError('Error writing to blob.')
self.offset += <int>buflen
def close(self):
self._close()
def reopen(self, rowid):
_check_blob_closed(self)
self.offset = 0
if sqlite3_blob_reopen(self.pBlob, <long long>rowid):
self._close()
raise OperationalError('Unable to re-open blob.')
def sqlite_get_status(flag):
cdef:
int current, highwater, rc
rc = sqlite3_status(flag, &current, &highwater, 0)
if rc == SQLITE_OK:
return (current, highwater)
raise Exception('Error requesting status: %s' % rc)
def sqlite_get_db_status(conn, flag):
cdef:
int current, highwater, rc
pysqlite_Connection *c_conn = <pysqlite_Connection *>conn
if not c_conn.db:
return (None, None)
rc = sqlite3_db_status(c_conn.db, flag, &current, &highwater, 0)
if rc == SQLITE_OK:
return (current, highwater)
raise Exception('Error requesting db status: %s' % rc)
cdef class ConnectionHelper(object):
cdef:
object _commit_hook, _rollback_hook, _update_hook
pysqlite_Connection *conn
def __init__(self, connection):
self.conn = <pysqlite_Connection *>connection
self._commit_hook = self._rollback_hook = self._update_hook = None
def __dealloc__(self):
# When deallocating a Database object, we need to ensure that we clear
# any commit, rollback or update hooks that may have been applied.
if not self.conn.initialized or not self.conn.db:
return
if self._commit_hook is not None:
sqlite3_commit_hook(self.conn.db, NULL, NULL)
if self._rollback_hook is not None:
sqlite3_rollback_hook(self.conn.db, NULL, NULL)
if self._update_hook is not None:
sqlite3_update_hook(self.conn.db, NULL, NULL)
def set_commit_hook(self, fn):
if not self.conn.initialized or not self.conn.db:
return
self._commit_hook = fn
if fn is None:
sqlite3_commit_hook(self.conn.db, NULL, NULL)
else:
sqlite3_commit_hook(self.conn.db, _commit_callback, <void *>fn)
def set_rollback_hook(self, fn):
if not self.conn.initialized or not self.conn.db:
return
self._rollback_hook = fn
if fn is None:
sqlite3_rollback_hook(self.conn.db, NULL, NULL)
else:
sqlite3_rollback_hook(self.conn.db, _rollback_callback, <void *>fn)
def set_update_hook(self, fn):
if not self.conn.initialized or not self.conn.db:
return
self._update_hook = fn
if fn is None:
sqlite3_update_hook(self.conn.db, NULL, NULL)
else:
sqlite3_update_hook(self.conn.db, _update_callback, <void *>fn)
def set_busy_handler(self, timeout=5):
"""
Replace the default busy handler with one that introduces some "jitter"
into the amount of time delayed between checks.
"""
if not self.conn.initialized or not self.conn.db:
return False
cdef sqlite3_int64 n = timeout * 1000
sqlite3_busy_handler(self.conn.db, _aggressive_busy_handler, <void *>n)
return True
def changes(self):
if self.conn.initialized and self.conn.db:
return sqlite3_changes(self.conn.db)
def last_insert_rowid(self):
if self.conn.initialized and self.conn.db:
return <int>sqlite3_last_insert_rowid(self.conn.db)
def autocommit(self):
if self.conn.initialized and self.conn.db:
return sqlite3_get_autocommit(self.conn.db) != 0
cdef int _commit_callback(void *userData) with gil:
# C-callback that delegates to the Python commit handler. If the Python
# function raises a ValueError, then the commit is aborted and the
# transaction rolled back. Otherwise, regardless of the function return
# value, the transaction will commit.
cdef object fn = <object>userData
try:
fn()
except ValueError:
return 1
else:
return SQLITE_OK
cdef void _rollback_callback(void *userData) with gil:
# C-callback that delegates to the Python rollback handler.
cdef object fn = <object>userData
fn()
cdef void _update_callback(void *userData, int queryType, const char *database,
const char *table, sqlite3_int64 rowid) with gil:
# C-callback that delegates to a Python function that is executed whenever
# the database is updated (insert/update/delete queries). The Python
# callback receives a string indicating the query type, the name of the
# database, the name of the table being updated, and the rowid of the row
# being updatd.
cdef object fn = <object>userData
if queryType == SQLITE_INSERT:
query = 'INSERT'
elif queryType == SQLITE_UPDATE:
query = 'UPDATE'
elif queryType == SQLITE_DELETE:
query = 'DELETE'
else:
query = ''
fn(query, decode(database), decode(table), <int>rowid)
def backup(src_conn, dest_conn, pages=None, name=None, progress=None):
cdef:
bytes bname = encode(name or 'main')
int page_step = pages or -1
int rc
pysqlite_Connection *src = <pysqlite_Connection *>src_conn
pysqlite_Connection *dest = <pysqlite_Connection *>dest_conn
sqlite3 *src_db = src.db
sqlite3 *dest_db = dest.db
sqlite3_backup *backup
if not src_db or not dest_db:
raise OperationalError('cannot backup to or from a closed database')
# We always backup to the "main" database in the dest db.
backup = sqlite3_backup_init(dest_db, b'main', src_db, bname)
if backup == NULL:
raise OperationalError('Unable to initialize backup.')
while True:
with nogil:
rc = sqlite3_backup_step(backup, page_step)
if progress is not None:
# Progress-handler is called with (remaining, page count, is done?)
remaining = sqlite3_backup_remaining(backup)
page_count = sqlite3_backup_pagecount(backup)
try:
progress(remaining, page_count, rc == SQLITE_DONE)
except:
sqlite3_backup_finish(backup)
raise
if rc == SQLITE_BUSY or rc == SQLITE_LOCKED:
with nogil:
sqlite3_sleep(250)
elif rc == SQLITE_DONE:
break
with nogil:
sqlite3_backup_finish(backup)
if sqlite3_errcode(dest_db):
raise OperationalError('Error backuping up database: %s' %
sqlite3_errmsg(dest_db))
return True
def backup_to_file(src_conn, filename, pages=None, name=None, progress=None):
dest_conn = pysqlite.connect(filename)
backup(src_conn, dest_conn, pages=pages, name=name, progress=progress)
dest_conn.close()
return True
cdef int _aggressive_busy_handler(void *ptr, int n) nogil:
# In concurrent environments, it often seems that if multiple queries are
# kicked off at around the same time, they proceed in lock-step to check
# for the availability of the lock. By introducing some "jitter" we can
# ensure that this doesn't happen. Furthermore, this function makes more
# attempts in the same time period than the default handler.
cdef:
sqlite3_int64 busyTimeout = <sqlite3_int64>ptr
int current, total
if n < 20:
current = 25 - (rand() % 10) # ~20ms
total = n * 20
elif n < 40:
current = 50 - (rand() % 20) # ~40ms
total = 400 + ((n - 20) * 40)
else:
current = 120 - (rand() % 40) # ~100ms
total = 1200 + ((n - 40) * 100) # Estimate the amount of time slept.
if total + current > busyTimeout:
current = busyTimeout - total
if current > 0:
sqlite3_sleep(current)
return 1
return 0