refactor(Maven): Extract LocalProjectWorkspaceReader

Move this inner class from `Maven` into a separate file and allow
customizing the lookup mechanism. This is a preparation for reusing
this functionality from other classes as well.

Signed-off-by: Oliver Heger <oliver.heger@bosch.io>

Author: oheger-bosch

plugins/package-managers/maven/src/main/kotlin/Maven.kt

@@ -23,10 +23,7 @@ import java.io.File
 
 import org.apache.maven.project.ProjectBuildingResult
 
-import org.eclipse.aether.artifact.Artifact
 import org.eclipse.aether.graph.DependencyNode
-import org.eclipse.aether.repository.WorkspaceReader
-import org.eclipse.aether.repository.WorkspaceRepository
 
 import org.ossreviewtoolkit.analyzer.AbstractPackageManagerFactory
 import org.ossreviewtoolkit.analyzer.PackageManager
@@ -41,10 +38,10 @@ import org.ossreviewtoolkit.model.config.AnalyzerConfiguration
 import org.ossreviewtoolkit.model.config.RepositoryConfiguration
 import org.ossreviewtoolkit.model.createAndLogIssue
 import org.ossreviewtoolkit.model.utils.DependencyGraphBuilder
+import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.LocalProjectWorkspaceReader
 import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.MavenDependencyHandler
 import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.MavenSupport
 import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.getOriginalScm
-import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.identifier
 import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.parseAuthors
 import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.parseLicenses
 import org.ossreviewtoolkit.plugins.packagemanagers.maven.utils.parseVcsInfo
@@ -77,22 +74,7 @@ class Maven(
         ) = Maven(type, analysisRoot, analyzerConfig, repoConfig)
     }
 
-    private inner class LocalProjectWorkspaceReader : WorkspaceReader {
-        private val workspaceRepository = WorkspaceRepository("maven/remote-artifacts")
-
-        override fun findArtifact(artifact: Artifact) =
-            artifact.takeIf { it.extension == "pom" }?.let {
-                localProjectBuildingResults[it.identifier()]?.pomFile?.absoluteFile
-            }
-
-        override fun findVersions(artifact: Artifact) =
-            // Avoid resolution of (SNAPSHOT) versions for local projects.
-            localProjectBuildingResults[artifact.identifier()]?.let { listOf(artifact.version) }.orEmpty()
-
-        override fun getRepository() = workspaceRepository
-    }
-
-    private val mavenSupport = MavenSupport(LocalProjectWorkspaceReader())
+    private val mavenSupport = MavenSupport(LocalProjectWorkspaceReader { localProjectBuildingResults[it]?.pomFile })
 
     private val localProjectBuildingResults = mutableMapOf<String, ProjectBuildingResult>()
 

plugins/package-managers/maven/src/main/kotlin/utils/LocalProjectWorkspaceReader.kt

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2017 The ORT Project Authors (see <https://github.com/oss-review-toolkit/ort/blob/main/NOTICE>)
+ *
+ * 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
+ *
+ *     https://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.plugins.packagemanagers.maven.utils
+
+import java.io.File
+
+import kotlin.collections.orEmpty
+
+import org.eclipse.aether.artifact.Artifact
+import org.eclipse.aether.repository.WorkspaceReader
+import org.eclipse.aether.repository.WorkspaceRepository
+
+/**
+ * A special implementation of the [WorkspaceReader] interface that is used by Maven package managers to resolve
+ * project artifacts. Projects are typically detected and handled specifically in concrete package manager
+ * implementations. Therefore, this class allows customizing the access to project definition files via a resolver
+ * function.
+ */
+internal class LocalProjectWorkspaceReader(
+    /**
+     * A function that can resolve an artifact identifier to a definition file if the artifact represents a local
+     * project. The function should return *null* for artifacts that are no local projects. This reader invokes
+     * the function to find out whether an artifact is a project and needs special treatment.
+     */
+    private val definitionFileResolveFun: (String) -> File?
+) : WorkspaceReader {
+    private val workspaceRepository = WorkspaceRepository("maven/remote-artifacts")
+
+    override fun findArtifact(artifact: Artifact) =
+        artifact.takeIf { it.extension == "pom" }?.let {
+            definitionFileResolveFun(it.identifier())?.absoluteFile
+        }
+
+    override fun findVersions(artifact: Artifact) =
+        // Avoid resolution of (SNAPSHOT) versions for local projects.
+        definitionFileResolveFun(artifact.identifier())?.let { listOf(artifact.version) }.orEmpty()
+
+    override fun getRepository() = workspaceRepository
+}