Have SConsignFile() use a dblite.py module by default, so we can control the behavior. (Ralf W. Grosse-Kunstleve)

1 files changed, 149 insertions, 0 deletions

diff --git a/src/engine/SCons/dblite.py b/src/engine/SCons/dblite.py
new file mode 100644
index 0000000..df04d80
--- /dev/null
+++ b/src/engine/SCons/dblite.py
@@ -0,0 +1,149 @@
+# dblite.py module contributed by Ralf W. Grosse-Kunstleve.
+
+import cPickle
+import time
+import shutil
+import os
+import __builtin__
+
+_open = __builtin__.open # avoid name clash
+
+keep_all_files = 00000
+ignore_corrupt_dbfiles = 0
+
+class dblite:
+
+  def __init__(self, file_base_name, flag, mode):
+    assert flag in (None, "r", "w", "c", "n")
+    if (flag is None): flag = "r"
+    if file_base_name[-7:] != '.dblite':
+        file_base_name = file_base_name + '.dblite'
+    self._file_name = file_base_name
+    self._flag = flag
+    self._mode = mode
+    self._dict = {}
+    self._needs_sync = 00000
+    if (self._flag == "n"):
+      _open(self._file_name, "wb", self._mode)
+    else:
+      try:
+        f = _open(self._file_name, "rb")
+      except IOError, e:
+        if (self._flag != "c"):
+          raise e
+        _open(self._file_name, "wb", self._mode)
+      else:
+        p = f.read()
+        if (len(p) > 0):
+          try:
+            self._dict = cPickle.loads(p)
+          except:
+            if (ignore_corrupt_dbfiles == 0): raise
+            if (ignore_corrupt_dbfiles == 1):
+              print "Warning: Discarding corrupt database:", self._file_name
+
+  def __del__(self):
+    if (self._needs_sync):
+      self.sync()
+
+  def sync(self):
+    self._check_writable()
+    f = _open(self._file_name, "wb", self._mode)
+    cPickle.dump(self._dict, f, 1)
+    f.close()
+    self._needs_sync = 00000
+    if (keep_all_files):
+      shutil.copyfile(
+        self._file_name,
+        self._file_name + "_" + str(int(time.time())))
+
+  def _check_writable(self):
+    if (self._flag == "r"):
+      raise IOError("Read-only database: %s" % self._file_name)
+
+  def __getitem__(self, key):
+    return self._dict[key]
+
+  def __setitem__(self, key, value):
+    self._check_writable()
+    if (type(key) != type("")):
+      raise TypeError, "key must be a string"
+    if (type(value) != type("")):
+      raise TypeError, "value must be a string"
+    self._dict[key] = value
+    self._needs_sync = 0001
+
+  def keys(self):
+    return self._dict.keys()
+
+  def has_key(self, key):
+    return key in self._dict
+
+  def __contains__(self, key):
+    return key in self._dict
+
+  def iterkeys(self):
+    return self._dict.iterkeys()
+
+  __iter__ = iterkeys
+
+  def __len__(self):
+    return len(self._dict)
+
+def open(file, flag=None, mode=0666):
+  return dblite(file, flag, mode)
+
+def _exercise():
+  db = open("tmp", "n")
+  assert len(db) == 0
+  db["foo"] = "bar"
+  assert db["foo"] == "bar"
+  db.sync()
+  db = open("tmp", "c")
+  assert len(db) == 1
+  assert db["foo"] == "bar"
+  db["bar"] = "foo"
+  assert db["bar"] == "foo"
+  db.sync()
+  db = open("tmp", "r")
+  assert len(db) == 2
+  assert db["foo"] == "bar"
+  assert db["bar"] == "foo"
+  try:
+    db.sync()
+  except IOError, e:
+    assert str(e) == "Read-only database: tmp.dblite"
+  else:
+    raise RuntimeError, "IOError expected."
+  db = open("tmp", "w")
+  assert len(db) == 2
+  db["ping"] = "pong"
+  db.sync()
+  db = open("tmp", "r")
+  assert len(db) == 3
+  db = open("tmp", "n")
+  assert len(db) == 0
+  _open("tmp.dblite", "w")
+  db = open("tmp", "r")
+  _open("tmp.dblite", "w").write("x")
+  try:
+    db = open("tmp", "r")
+  except cPickle.UnpicklingError:
+    pass
+  else:
+    raise RuntimeError, "cPickle exception expected."
+  global ignore_corrupt_dbfiles
+  ignore_corrupt_dbfiles = 2
+  db = open("tmp", "r")
+  assert len(db) == 0
+  os.unlink("tmp.dblite")
+  try:
+    db = open("tmp", "w")
+  except IOError, e:
+    assert str(e) == "Database does not exist: tmp.dblite"
+  else:
+    raise RuntimeError, "IOError expected."
+  print "OK"
+
+if (__name__ == "__main__"):
+  _exercise()