analyzer: Add a generic SPDX-document-based "fake" package manager

See spdx/spdx-spec#439 for details.

Signed-off-by: Sebastian Schuberth <sebastian.schuberth@bosch.io>

analyzer/src/main/kotlin/managers/SpdxDocumentFile.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2020 Bosch.IO GmbH
+ *
+ * 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * License-Filename: LICENSE
+ */
+
+package org.ossreviewtoolkit.analyzer.managers
+
+import java.io.File
+
+import org.ossreviewtoolkit.analyzer.AbstractPackageManagerFactory
+import org.ossreviewtoolkit.analyzer.PackageManager
+import org.ossreviewtoolkit.model.ProjectAnalyzerResult
+import org.ossreviewtoolkit.model.config.AnalyzerConfiguration
+import org.ossreviewtoolkit.model.config.RepositoryConfiguration
+
+/**
+ * A "fake" package manager implementation that uses SPDX documents as "marker" files to declare projects and describe
+ * packages. See https://github.com/spdx/spdx-spec/issues/439 for details.
+ */
+class SpdxDocumentFile(
+    managerName: String,
+    analysisRoot: File,
+    analyzerConfig: AnalyzerConfiguration,
+    repoConfig: RepositoryConfiguration
+) : PackageManager(managerName, analysisRoot, analyzerConfig, repoConfig) {
+    class Factory : AbstractPackageManagerFactory<SpdxDocumentFile>("SpdxDocumentFile") {
+        override val globsForDefinitionFiles = listOf("*.spdx.yml", "*.spdx.yaml", "*.spdx.json")
+
+        override fun create(
+            analysisRoot: File,
+            analyzerConfig: AnalyzerConfiguration,
+            repoConfig: RepositoryConfiguration
+        ) = SpdxDocumentFile(managerName, analysisRoot, analyzerConfig, repoConfig)
+    }
+
+    override fun resolveDependencies(definitionFile: File): List<ProjectAnalyzerResult> {
+        val results = mutableListOf<ProjectAnalyzerResult>()
+
+        val workingDir = definitionFile.parentFile
+
+        return results
+    }
+}

analyzer/src/main/resources/META-INF/services/org.ossreviewtoolkit.analyzer.PackageManagerFactory

@@ -14,5 +14,6 @@ org.ossreviewtoolkit.analyzer.managers.Pip$Factory
 org.ossreviewtoolkit.analyzer.managers.Pipenv$Factory
 org.ossreviewtoolkit.analyzer.managers.Pub$Factory
 org.ossreviewtoolkit.analyzer.managers.Sbt$Factory
+org.ossreviewtoolkit.analyzer.managers.SpdxDocumentFile$Factory
 org.ossreviewtoolkit.analyzer.managers.Stack$Factory
 org.ossreviewtoolkit.analyzer.managers.Yarn$Factory