python学习

venv/Lib/site-packages/flask_sqlalchemy/utils.py

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+import warnings
+
+import sqlalchemy
+
+
+def parse_version(v):
+    """
+        Take a string version and conver it to a tuple (for easier comparison), e.g.:
+
+            "1.2.3" --> (1, 2, 3)
+            "1.2" --> (1, 2, 0)
+            "1" --> (1, 0, 0)
+    """
+    parts = v.split(".")
+    # Pad the list to make sure there is three elements so that we get major, minor, point
+    # comparisons that default to "0" if not given.  I.e. "1.2" --> (1, 2, 0)
+    parts = (parts + 3 * ['0'])[:3]
+    return tuple(int(x) for x in parts)
+
+
+def sqlalchemy_version(op, val):
+    sa_ver = parse_version(sqlalchemy.__version__)
+    target_ver = parse_version(val)
+
+    assert op in ('<', '>', '<=', '>=', '=='), 'op {} not supported'.format(op)
+
+    if op == '<':
+        return sa_ver < target_ver
+    if op == '>':
+        return sa_ver > target_ver
+    if op == '<=':
+        return sa_ver <= target_ver
+    if op == '>=':
+        return sa_ver >= target_ver
+    return sa_ver == target_ver
+
+
+def engine_config_warning(config, version, deprecated_config_key, engine_option):
+    if config[deprecated_config_key] is not None:
+        warnings.warn(
+            'The `{}` config option is deprecated and will be removed in'
+            ' v{}.  Use `SQLALCHEMY_ENGINE_OPTIONS[\'{}\']` instead.'
+            .format(deprecated_config_key, version, engine_option),
+            DeprecationWarning
+        )