Import PyBSDDB 3.4.0. Rename historical wrapper to bsddb185.

1 files changed, 190 insertions, 0 deletions

diff --git a/Lib/bsddb/dbrecio.py b/Lib/bsddb/dbrecio.py
new file mode 100644
index 0000000..995dad7
--- /dev/null
+++ b/Lib/bsddb/dbrecio.py
@@ -0,0 +1,190 @@
+
+"""
+File-like objects that read from or write to a bsddb3 record.
+
+This implements (nearly) all stdio methods.
+
+f = DBRecIO(db, key, txn=None)
+f.close()           # explicitly release resources held
+flag = f.isatty()   # always false
+pos = f.tell()      # get current position
+f.seek(pos)         # set current position
+f.seek(pos, mode)   # mode 0: absolute; 1: relative; 2: relative to EOF
+buf = f.read()      # read until EOF
+buf = f.read(n)     # read up to n bytes
+f.truncate([size])  # truncate file at to at most size (default: current pos)
+f.write(buf)        # write at current position
+f.writelines(list)  # for line in list: f.write(line)
+
+Notes:
+- fileno() is left unimplemented so that code which uses it triggers
+  an exception early.
+- There's a simple test set (see end of this file) - not yet updated
+  for DBRecIO.
+- readline() is not implemented yet.
+
+
+From:
+    Itamar Shtull-Trauring <itamar@maxnm.com>
+"""
+
+import errno
+import string
+
+class DBRecIO:
+    def __init__(self, db, key, txn=None):
+        self.db = db
+        self.key = key
+        self.txn = txn
+        self.len = None
+        self.pos = 0
+        self.closed = 0
+        self.softspace = 0
+
+    def close(self):
+        if not self.closed:
+            self.closed = 1
+            del self.db, self.txn
+
+    def isatty(self):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        return 0
+
+    def seek(self, pos, mode = 0):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        if mode == 1:
+            pos = pos + self.pos
+        elif mode == 2:
+            pos = pos + self.len
+        self.pos = max(0, pos)
+
+    def tell(self):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        return self.pos
+
+    def read(self, n = -1):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        if n < 0:
+            newpos = self.len
+        else:
+            newpos = min(self.pos+n, self.len)
+
+        dlen = newpos - self.pos
+
+        r = self.db.get(key, txn=self.txn, dlen=dlen, doff=self.pos)
+        self.pos = newpos
+        return r
+
+    __fixme = """
+    def readline(self, length=None):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        if self.buflist:
+            self.buf = self.buf + string.joinfields(self.buflist, '')
+            self.buflist = []
+        i = string.find(self.buf, '\n', self.pos)
+        if i < 0:
+            newpos = self.len
+        else:
+            newpos = i+1
+        if length is not None:
+            if self.pos + length < newpos:
+                newpos = self.pos + length
+        r = self.buf[self.pos:newpos]
+        self.pos = newpos
+        return r
+
+    def readlines(self, sizehint = 0):
+        total = 0
+        lines = []
+        line = self.readline()
+        while line:
+            lines.append(line)
+            total += len(line)
+            if 0 < sizehint <= total:
+                break
+            line = self.readline()
+        return lines
+    """
+
+    def truncate(self, size=None):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        if size is None:
+            size = self.pos
+        elif size < 0:
+            raise IOError(errno.EINVAL,
+                                      "Negative size not allowed")
+        elif size < self.pos:
+            self.pos = size
+        self.db.put(key, "", txn=self.txn, dlen=self.len-size, doff=size)
+
+    def write(self, s):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+        if not s: return
+        if self.pos > self.len:
+            self.buflist.append('\0'*(self.pos - self.len))
+            self.len = self.pos
+        newpos = self.pos + len(s)
+        self.db.put(key, s, txn=self.txn, dlen=len(s), doff=self.pos)
+        self.pos = newpos
+
+    def writelines(self, list):
+        self.write(string.joinfields(list, ''))
+
+    def flush(self):
+        if self.closed:
+            raise ValueError, "I/O operation on closed file"
+
+
+"""
+# A little test suite
+
+def _test():
+    import sys
+    if sys.argv[1:]:
+        file = sys.argv[1]
+    else:
+        file = '/etc/passwd'
+    lines = open(file, 'r').readlines()
+    text = open(file, 'r').read()
+    f = StringIO()
+    for line in lines[:-2]:
+        f.write(line)
+    f.writelines(lines[-2:])
+    if f.getvalue() != text:
+        raise RuntimeError, 'write failed'
+    length = f.tell()
+    print 'File length =', length
+    f.seek(len(lines[0]))
+    f.write(lines[1])
+    f.seek(0)
+    print 'First line =', `f.readline()`
+    here = f.tell()
+    line = f.readline()
+    print 'Second line =', `line`
+    f.seek(-len(line), 1)
+    line2 = f.read(len(line))
+    if line != line2:
+        raise RuntimeError, 'bad result after seek back'
+    f.seek(len(line2), 1)
+    list = f.readlines()
+    line = list[-1]
+    f.seek(f.tell() - len(line))
+    line2 = f.read()
+    if line != line2:
+        raise RuntimeError, 'bad result after seek back from EOF'
+    print 'Read', len(list), 'more lines'
+    print 'File length =', f.tell()
+    if f.tell() != length:
+        raise RuntimeError, 'bad length'
+    f.close()
+
+if __name__ == '__main__':
+    _test()
+"""