Import PyBSDDB 3.4.0. Rename historical wrapper to bsddb185.

Lib/bsddb/dbtables.py

@@ -0,0 +1,629 @@
+#-----------------------------------------------------------------------
+#
+# Copyright (C) 2000, 2001 by Autonomous Zone Industries
+#
+# License:      This is free software.  You may use this software for any
+#               purpose including modification/redistribution, so long as
+#               this header remains intact and that you do not claim any
+#               rights of ownership or authorship of this software.  This
+#               software has been tested, but no warranty is expressed or
+#               implied.
+#
+#   --  Gregory P. Smith <greg@electricrain.com>
+
+# This provides a simple database table interface built on top of
+# the Python BerkeleyDB 3 interface.
+#
+_cvsid = '$Id$'
+
+import string
+import sys
+try:
+    import cPickle
+    pickle = cPickle
+except ImportError:
+    import pickle
+import whrandom
+import xdrlib
+import re
+import copy
+
+from bsddb3.db import *
+
+
+class TableDBError(StandardError): pass
+class TableAlreadyExists(TableDBError): pass
+
+
+class Cond:
+    """This condition matches everything"""
+    def __call__(self, s):
+        return 1
+
+class ExactCond(Cond):
+    """Acts as an exact match condition function"""
+    def __init__(self, strtomatch):
+        self.strtomatch = strtomatch
+    def __call__(self, s):
+        return s == self.strtomatch
+
+class PrefixCond(Cond):
+    """Acts as a condition function for matching a string prefix"""
+    def __init__(self, prefix):
+        self.prefix = prefix
+    def __call__(self, s):
+        return s[:len(self.prefix)] == self.prefix
+
+class LikeCond(Cond):
+    """
+    Acts as a function that will match using an SQL 'LIKE' style
+    string.  Case insensitive and % signs are wild cards.
+    This isn't perfect but it should work for the simple common cases.
+    """
+    def __init__(self, likestr, re_flags=re.IGNORECASE):
+        # escape python re characters
+        chars_to_escape = '.*+()[]?'
+        for char in chars_to_escape :
+            likestr = string.replace(likestr, char, '\\'+char)
+        # convert %s to wildcards
+        self.likestr = string.replace(likestr, '%', '.*')
+        self.re = re.compile('^'+self.likestr+'$', re_flags)
+    def __call__(self, s):
+        return self.re.match(s)
+
+#
+# keys used to store database metadata
+#
+_table_names_key = '__TABLE_NAMES__'  # list of the tables in this db
+_columns = '._COLUMNS__'  # table_name+this key contains a list of columns
+def _columns_key(table) : return table + _columns
+
+#
+# these keys are found within table sub databases
+#
+_data =  '._DATA_.'  # this+column+this+rowid key contains table data
+_rowid = '._ROWID_.' # this+rowid+this key contains a unique entry for each
+                     # row in the table.  (no data is stored)
+_rowid_str_len = 8   # length in bytes of the unique rowid strings
+def _data_key(table, col, rowid) : return table + _data + col + _data + rowid
+def _search_col_data_key(table, col) : return table + _data + col + _data
+def _search_all_data_key(table) : return table + _data
+def _rowid_key(table, rowid) : return table + _rowid + rowid + _rowid
+def _search_rowid_key(table) : return table + _rowid
+
+def contains_metastrings(s) :
+    """Verify that the given string does not contain any
+    metadata strings that might interfere with dbtables database operation.
+    """
+    if string.find(s, _table_names_key) >= 0 or \
+       string.find(s, _columns) >= 0 or \
+       string.find(s, _data) >= 0 or \
+       string.find(s, _rowid) >= 0 :
+        return 1
+    else :
+        return 0
+
+
+class bsdTableDB :
+    def __init__(self, filename, dbhome, create=0, truncate=0, mode=0600, recover=0, dbflags=0) :
+        """bsdTableDB.open(filename, dbhome, create=0, truncate=0, mode=0600)
+        Open database name in the dbhome BerkeleyDB directory.
+        Use keyword arguments when calling this constructor.
+        """
+        myflags = DB_THREAD
+        if create :
+            myflags = myflags | DB_CREATE
+        flagsforenv = DB_INIT_MPOOL | DB_INIT_LOCK | DB_INIT_LOG | DB_INIT_TXN | dbflags
+        if recover :
+            flagsforenv = flagsforenv | DB_RECOVER
+        self.env = DBEnv()
+        self.env.set_lk_detect(DB_LOCK_DEFAULT)  # enable auto deadlock avoidance
+        self.env.open(dbhome, myflags | flagsforenv)
+        if truncate :
+            myflags = myflags | DB_TRUNCATE
+        self.db = DB(self.env)
+        self.db.set_flags(DB_DUP)  # allow duplicate entries [warning: be careful w/ metadata]
+        self.db.open(filename, DB_BTREE, myflags, mode)
+
+        self.dbfilename = filename
+
+        # Initialize the table names list if this is a new database
+        if not self.db.has_key(_table_names_key) :
+            self.db.put(_table_names_key, pickle.dumps([], 1))
+
+        # TODO verify more of the database's metadata?
+
+        self.__tablecolumns = {}
+
+    def __del__(self):
+        self.close()
+
+    def close(self):
+        if self.db is not None:
+            self.db.close()
+            self.db = None
+        if self.env is not None:
+            self.env.close()
+            self.env = None
+
+    def checkpoint(self, mins=0):
+        try:
+            self.env.txn_checkpoint(mins)
+        except DBIncompleteError:
+            pass
+
+    def sync(self):
+        try:
+            self.db.sync()
+        except DBIncompleteError:
+            pass
+
+    def _db_print(self) :
+        """Print the database to stdout for debugging"""
+        print "******** Printing raw database for debugging ********"
+        cur = self.db.cursor()
+        try:
+            key, data = cur.first()
+            while 1 :
+                print `{key: data}`
+                next = cur.next()
+                if next:
+                    key, data = next
+                else:
+                    cur.close()
+                    return
+        except DBNotFoundError:
+            cur.close()
+
+
+    def CreateTable(self, table, columns) :
+        """CreateTable(table, columns) - Create a new table in the database
+        raises TableDBError if it already exists or for other DB errors.
+        """
+        assert type(columns) == type([])
+        txn = None
+        try:
+            # checking sanity of the table and column names here on
+            # table creation will prevent problems elsewhere.
+            if contains_metastrings(table) :
+                raise ValueError, "bad table name: contains reserved metastrings"
+            for column in columns :
+                if contains_metastrings(column) :
+                    raise ValueError, "bad column name: contains reserved metastrings"
+
+            columnlist_key = _columns_key(table)
+            if self.db.has_key(columnlist_key) :
+                raise TableAlreadyExists, "table already exists"
+
+            txn = self.env.txn_begin()
+            # store the table's column info
+            self.db.put(columnlist_key, pickle.dumps(columns, 1), txn=txn)
+
+            # add the table name to the tablelist
+            tablelist = pickle.loads(self.db.get(_table_names_key, txn=txn, flags=DB_RMW))
+            tablelist.append(table)
+            self.db.delete(_table_names_key, txn)  # delete 1st, incase we opened with DB_DUP
+            self.db.put(_table_names_key, pickle.dumps(tablelist, 1), txn=txn)
+
+            txn.commit()
+            txn = None
+
+        except DBError, dberror:
+            if txn :
+                txn.abort()
+            raise TableDBError, dberror[1]
+
+
+    def ListTableColumns(self, table):
+        """Return a list of columns in the given table.  [] if the table doesn't exist.
+        """
+        assert type(table) == type('')
+        if contains_metastrings(table) :
+            raise ValueError, "bad table name: contains reserved metastrings"
+
+        columnlist_key = _columns_key(table)
+        if not self.db.has_key(columnlist_key):
+            return []
+        pickledcolumnlist = self.db.get(columnlist_key)
+        if pickledcolumnlist:
+            return pickle.loads(pickledcolumnlist)
+        else:
+            return []
+
+    def ListTables(self):
+        """Return a list of tables in this database."""
+        pickledtablelist = self.db.get(_table_names_key)
+        if pickledtablelist:
+            return pickle.loads(pickledtablelist)
+        else:
+            return []
+
+    def CreateOrExtendTable(self, table, columns):
+        """CreateOrExtendTable(table, columns) - Create a new table in the database.
+        If a table of this name already exists, extend it to have any
+        additional columns present in the given list as well as
+        all of its current columns.
+        """
+        assert type(columns) == type([])
+        try:
+            self.CreateTable(table, columns)
+        except TableAlreadyExists:
+            # the table already existed, add any new columns
+            txn = None
+            try:
+                columnlist_key = _columns_key(table)
+                txn = self.env.txn_begin()
+
+                # load the current column list
+                oldcolumnlist = pickle.loads(self.db.get(columnlist_key, txn=txn, flags=DB_RMW))
+                # create a hash table for fast lookups of column names in the loop below
+                oldcolumnhash = {}
+                for c in oldcolumnlist:
+                    oldcolumnhash[c] = c
+
+                # create a new column list containing both the old and new column names
+                newcolumnlist = copy.copy(oldcolumnlist)
+                for c in columns:
+                    if not oldcolumnhash.has_key(c):
+                        newcolumnlist.append(c)
+
+                # store the table's new extended column list
+                if newcolumnlist != oldcolumnlist :
+                    # delete the old one first since we opened with DB_DUP
+                    self.db.delete(columnlist_key, txn)
+                    self.db.put(columnlist_key, pickle.dumps(newcolumnlist, 1), txn=txn)
+
+                txn.commit()
+                txn = None
+
+                self.__load_column_info(table)
+            except DBError, dberror:
+                if txn:
+                    txn.abort()
+                raise TableDBError, dberror[1]
+
+
+    def __load_column_info(self, table) :
+        """initialize the self.__tablecolumns dict"""
+        # check the column names
+        try:
+            tcolpickles = self.db.get(_columns_key(table))
+        except DBNotFoundError:
+            raise TableDBError, "unknown table: " + `table`
+        if not tcolpickles:
+            raise TableDBError, "unknown table: " + `table`
+        self.__tablecolumns[table] = pickle.loads(tcolpickles)
+
+    def __new_rowid(self, table, txn=None) :
+        """Create a new unique row identifier"""
+        unique = 0
+        while not unique :
+            # Generate a random 64-bit row ID string
+            # (note: this code has <64 bits of randomness
+            # but it's plenty for our database id needs!)
+            p = xdrlib.Packer()
+            p.pack_int(int(whrandom.random()*2147483647))
+            p.pack_int(int(whrandom.random()*2147483647))
+            newid = p.get_buffer()
+
+            # Guarantee uniqueness by adding this key to the database
+            try:
+                self.db.put(_rowid_key(table, newid), None, txn=txn, flags=DB_NOOVERWRITE)
+            except DBKeyExistsError:
+                pass
+            else:
+                unique = 1
+
+        return newid
+
+
+    def Insert(self, table, rowdict) :
+        """Insert(table, datadict) - Insert a new row into the table
+        using the keys+values from rowdict as the column values.
+        """
+        txn = None
+        try:
+            if not self.db.has_key(_columns_key(table)) :
+                raise TableDBError, "unknown table"
+
+            # check the validity of each column name
+            if not self.__tablecolumns.has_key(table) :
+                self.__load_column_info(table)
+            for column in rowdict.keys() :
+                if not self.__tablecolumns[table].count(column) :
+                    raise TableDBError, "unknown column: "+`column`
+
+            # get a unique row identifier for this row
+            rowid = self.__new_rowid(table)
+
+            txn = self.env.txn_begin()
+
+            # insert the row values into the table database
+            for column, dataitem in rowdict.items() :
+                # store the value
+                self.db.put(_data_key(table, column, rowid), dataitem, txn=txn)
+
+            txn.commit()
+            txn = None
+
+        except DBError, dberror:
+            if txn :
+                txn.abort()
+                self.db.delete(_rowid_key(table, rowid))
+            raise TableDBError, dberror[1]
+
+
+    def Modify(self, table, conditions={}, mappings={}) :
+        """Modify(table, conditions) - Modify in rows matching 'conditions'
+        using mapping functions in 'mappings'
+        * conditions is a dictionary keyed on column names
+        containing condition functions expecting the data string as an
+        argument and returning a boolean.
+        * mappings is a dictionary keyed on column names containint condition
+        functions expecting the data string as an argument and returning the
+        new string for that column.
+        """
+        try:
+            matching_rowids = self.__Select(table, [], conditions)
+
+            # modify only requested columns
+            columns = mappings.keys()
+            for rowid in matching_rowids.keys() :
+                txn = None
+                try:
+                    for column in columns :
+                        txn = self.env.txn_begin()
+                        # modify the requested column
+                        try:
+                            dataitem = self.db.get(_data_key(table, column, rowid), txn)
+                            self.db.delete(_data_key(table, column, rowid), txn)
+                        except DBNotFoundError:
+                            dataitem = None # XXXXXXX row key somehow didn't exist, assume no error
+                        dataitem = mappings[column](dataitem)
+                        if dataitem <> None:
+                            self.db.put(_data_key(table, column, rowid), dataitem, txn=txn)
+                        txn.commit()
+                        txn = None
+
+                except DBError, dberror:
+                    if txn :
+                        txn.abort()
+                    raise
+
+        except DBError, dberror:
+            raise TableDBError, dberror[1]
+
+    def Delete(self, table, conditions={}) :
+        """Delete(table, conditions) - Delete items matching the given
+        conditions from the table.
+        * conditions is a dictionary keyed on column names
+        containing condition functions expecting the data string as an
+        argument and returning a boolean.
+        """
+        try:
+            matching_rowids = self.__Select(table, [], conditions)
+
+            # delete row data from all columns
+            columns = self.__tablecolumns[table]
+            for rowid in matching_rowids.keys() :
+                txn = None
+                try:
+                    txn = self.env.txn_begin()
+                    for column in columns :
+                        # delete the data key
+                        try:
+                            self.db.delete(_data_key(table, column, rowid), txn)
+                        except DBNotFoundError:
+                            pass # XXXXXXX column may not exist, assume no error
+
+                    try:
+                        self.db.delete(_rowid_key(table, rowid), txn)
+                    except DBNotFoundError:
+                        pass # XXXXXXX row key somehow didn't exist, assume no error
+                    txn.commit()
+                    txn = None
+                except DBError, dberror:
+                    if txn :
+                        txn.abort()
+                    raise
+
+        except DBError, dberror:
+            raise TableDBError, dberror[1]
+
+
+    def Select(self, table, columns, conditions={}) :
+        """Select(table, conditions) - retrieve specific row data
+        Returns a list of row column->value mapping dictionaries.
+        * columns is a list of which column data to return.  If
+          columns is None, all columns will be returned.
+        * conditions is a dictionary keyed on column names
+          containing callable conditions expecting the data string as an
+          argument and returning a boolean.
+        """
+        try:
+            if not self.__tablecolumns.has_key(table) :
+                self.__load_column_info(table)
+            if columns is None :
+                columns = self.__tablecolumns[table]
+            matching_rowids = self.__Select(table, columns, conditions)
+        except DBError, dberror:
+            raise TableDBError, dberror[1]
+
+        # return the matches as a list of dictionaries
+        return matching_rowids.values()
+
+
+    def __Select(self, table, columns, conditions) :
+        """__Select() - Used to implement Select and Delete (above)
+        Returns a dictionary keyed on rowids containing dicts
+        holding the row data for columns listed in the columns param
+        that match the given conditions.
+        * conditions is a dictionary keyed on column names
+        containing callable conditions expecting the data string as an
+        argument and returning a boolean.
+        """
+        # check the validity of each column name
+        if not self.__tablecolumns.has_key(table) :
+            self.__load_column_info(table)
+        if columns is None :
+            columns = self.tablecolumns[table]
+        for column in (columns + conditions.keys()) :
+            if not self.__tablecolumns[table].count(column) :
+                raise TableDBError, "unknown column: "+`column`
+
+        # keyed on rows that match so far, containings dicts keyed on
+        # column names containing the data for that row and column.
+        matching_rowids = {}
+
+        rejected_rowids = {} # keys are rowids that do not match
+
+        # attempt to sort the conditions in such a way as to minimize full column lookups
+        def cmp_conditions(atuple, btuple):
+            a = atuple[1]
+            b = btuple[1]
+            if type(a) == type(b) :
+                if isinstance(a, PrefixCond) and isinstance(b, PrefixCond):
+                    return cmp(len(b.prefix), len(a.prefix))  # longest prefix first
+                if isinstance(a, LikeCond) and isinstance(b, LikeCond):
+                    return cmp(len(b.likestr), len(a.likestr))  # longest likestr first
+                return 0
+            if isinstance(a, ExactCond):
+                return -1
+            if isinstance(b, ExactCond):
+                return 1
+            if isinstance(a, PrefixCond):
+                return -1
+            if isinstance(b, PrefixCond):
+                return 1
+            # leave all unknown condition callables alone as equals
+            return 0
+
+        conditionlist = conditions.items()
+        conditionlist.sort(cmp_conditions)
+
+        # Apply conditions to column data to find what we want
+        cur = self.db.cursor()
+        column_num = -1
+        for column, condition in conditionlist :
+            column_num = column_num + 1
+            searchkey = _search_col_data_key(table, column)
+            # speedup: don't linear search columns within loop
+            if column in columns :
+                savethiscolumndata = 1  # save the data for return
+            else :
+                savethiscolumndata = 0  # data only used for selection
+
+            try:
+                key, data = cur.set_range(searchkey)
+                while key[:len(searchkey)] == searchkey :
+                    # extract the rowid from the key
+                    rowid = key[-_rowid_str_len:]
+
+                    if not rejected_rowids.has_key(rowid) :
+                        # if no condition was specified or the condition
+                        # succeeds, add row to our match list.
+                        if not condition or condition(data) :
+                            # only create new entries in matcing_rowids on
+                            # the first pass, otherwise reject the
+                            # rowid as it must not have matched
+                            # the previous passes
+                            if column_num == 0 :
+                                if not matching_rowids.has_key(rowid) :
+                                    matching_rowids[rowid] = {}
+                                if savethiscolumndata :
+                                    matching_rowids[rowid][column] = data
+                            else :
+                                rejected_rowids[rowid] = rowid
+                        else :
+                            if matching_rowids.has_key(rowid) :
+                                del matching_rowids[rowid]
+                            rejected_rowids[rowid] = rowid
+
+                    key, data = cur.next()
+
+            except DBError, dberror:
+                if dberror[0] != DB_NOTFOUND :
+                    raise
+                continue
+
+        cur.close()
+
+        # we're done selecting rows, garbage collect the reject list
+        del rejected_rowids
+
+        # extract any remaining desired column data from the
+        # database for the matching rows.
+        if len(columns) > 0 :
+            for rowid, rowdata in matching_rowids.items() :
+                for column in columns :
+                    if rowdata.has_key(column) :
+                        continue
+                    try:
+                        rowdata[column] = self.db.get(_data_key(table, column, rowid))
+                    except DBError, dberror:
+                        if dberror[0] != DB_NOTFOUND :
+                            raise
+                        rowdata[column] = None
+
+        # return the matches
+        return matching_rowids
+
+
+    def Drop(self, table) :
+        """Remove an entire table from the database
+        """
+        txn = None
+        try:
+            txn = self.env.txn_begin()
+
+            # delete the column list
+            self.db.delete(_columns_key(table), txn)
+
+            cur = self.db.cursor(txn)
+
+            # delete all keys containing this tables column and row info
+            table_key = _search_all_data_key(table)
+            while 1 :
+                try:
+                    key, data = cur.set_range(table_key)
+                except DBNotFoundError:
+                    break
+                # only delete items in this table
+                if key[:len(table_key)] != table_key :
+                    break
+                cur.delete()
+
+            # delete all rowids used by this table
+            table_key = _search_rowid_key(table)
+            while 1 :
+                try:
+                    key, data = cur.set_range(table_key)
+                except DBNotFoundError:
+                    break
+                # only delete items in this table
+                if key[:len(table_key)] != table_key :
+                    break
+                cur.delete()
+
+            cur.close()
+
+            # delete the tablename from the table name list
+            tablelist = pickle.loads(self.db.get(_table_names_key, txn=txn, flags=DB_RMW))
+            try:
+                tablelist.remove(table)
+            except ValueError:
+                pass  # hmm, it wasn't there, oh well, that's what we want.
+            self.db.delete(_table_names_key, txn)  # delete 1st, incase we opened with DB_DUP
+            self.db.put(_table_names_key, pickle.dumps(tablelist, 1), txn=txn)
+
+            txn.commit()
+            txn = None
+
+            if self.__tablecolumns.has_key(table) :
+                del self.__tablecolumns[table]
+
+        except DBError, dberror:
+            if txn :
+                txn.abort()
+            raise TableDBError, dberror[1]
+