Add initial code

Signed-off-by: Jono Yang <jyang@nexb.com>

Author: JonoYang

setup.cfg

@@ -1,12 +1,12 @@
 [metadata]
-name = skeleton
+name = purl-validator
 license = Apache-2.0
 
 # description must be on ONE line https://github.com/pypa/setuptools/issues/1390
-description = skeleton
+description = purl-validator
 long_description = file:README.rst
 long_description_content_type = text/x-rst
-url = https://github.com/aboutcode-org/skeleton
+url = https://github.com/aboutcode-org/purl-validator
 
 author = nexB. Inc. and others
 author_email = info@aboutcode.org
@@ -43,6 +43,8 @@ setup_requires = setuptools_scm[toml] >= 4
 
 
 install_requires =
+    commoncode
+    ducer
 
 
 [options.packages.find]

src/README.rst

@@ -0,0 +1,111 @@
+#
+# Copyright (c) nexB Inc. and others.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Visit https://aboutcode.org and https://github.com/aboutcode-org/ for support and download.
+# ScanCode is a trademark of nexB Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from pathlib import Path
+import mmap
+
+from commoncode import fileutils
+from packageurl import PackageURL
+import ducer
+
+
+PURLS = """
+pkg:maven/be.sweetmustard.vinegar/vinegar-pattern-matcher@0.1.1
+pkg:maven/be.sweetmustard.vinegar/vinegar-pattern-matcher@0.1.1?classifier=sources
+pkg:maven/be.sweetmustard.vinegar/vinegar-pattern-matcher@0.1.0
+pkg:maven/be.sweetmustard.vinegar/vinegar-pattern-matcher@0.1.0?classifier=sources
+""".split()
+
+
+def create_purl_map(purls):
+    # Ensure elements of `purls` are strings:
+    purl_strs = []
+    for purl in purls:
+        if not isinstance(purl, (PackageURL, str)):
+            raise ValueError(f"invalid purl in `purls`: {purl}")
+        if isinstance(purl, PackageURL):
+            purl_str = purl.to_string()
+        else:
+            purl_str = purl
+        purl_strs.append(purl_str)
+
+    # purl strs must be sorted and converted to bytes before going into the Map
+    prepared_purl_strs = [(bytes(purl_str, "utf-8"), 1) for purl_str in sorted(purl_strs)]
+
+    # create map
+    temp_dir = fileutils.get_temp_dir()
+    map_loc = Path(temp_dir) / "purls.map"
+    ducer.Map.build(map_loc, prepared_purl_strs)
+
+    return map_loc
+
+
+class PurlValidator:
+    def __init__(self, purl_map_loc=None):
+        self.created_maps = []
+
+        if purl_map_loc:
+            if not isinstance(purl_map_loc, (Path, str)):
+                raise ValueError("`purl_map_loc` must be a Path or path string")
+            if not isinstance(purl_map_loc, Path):
+                # Ensure purl_map_loc is a Path
+                purl_map_loc = Path(purl_map_loc)
+        else:
+            # Create purl map from PURLS
+            purl_map_loc = self.create_purl_map(purls=PURLS)
+
+        self.purl_map = self.load_purl_map(location=purl_map_loc)
+
+    def __del__(self):
+        for loc in self.created_maps:
+            fileutils.delete(loc.parent)
+
+    def create_purl_map(self, purls):
+        purl_map_loc = create_purl_map(purls)
+        self.created_maps.append(purl_map_loc)
+        return purl_map_loc
+
+    def load_purl_map(self, location):
+        with open(location, "rb") as f:
+            mm = mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ)
+        m = ducer.Map(mm)
+        return m
+
+    def validate_purl(self, purl):
+        if not isinstance(purl, (PackageURL, str)):
+            raise ValueError("`purl` must be a PackageURL or purl string")
+
+        # Ensure `purl` is a PackageURL
+        if isinstance(purl, str):
+            purl = PackageURL.from_string(purl)
+
+        # Convert purl to bytes
+        purl_bytes = bytes(purl.to_string(), "utf-8")
+
+        return bool(self.purl_map.get(purl_bytes))
+
+
+if __name__ == "__main__":
+    purl_validator = PurlValidator()
+    print(
+        purl_validator.validate_purl(
+            "pkg:maven/be.sweetmustard.vinegar/vinegar-pattern-matcher@0.1.1"
+        )
+    )