CleanupEmptyListsDeep: recursive empty-list pruner for merged BOMs (5/5)

src/CycloneDX.Core/BomRefWalker.cs

@@ -0,0 +1,205 @@
+// This file is part of CycloneDX Library for .NET
+//
+// 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
+// Copyright (c) OWASP Foundation. All Rights Reserved.
+
+#if NET8_0_OR_GREATER
+using System;
+using System.Collections.Generic;
+using CycloneDX.Models;
+using CycloneDX.Models.Vulnerabilities;
+
+namespace CycloneDX
+{
+    /// <summary>
+    /// Rewrites every "bom-ref"-shaped value in a <see cref="Bom"/> document
+    /// -- both identifiers (Component/Service/Vulnerability/Annotation
+    /// BomRef) and back-references to them (Dependency.Ref, Composition's
+    /// Assemblies/Dependencies string lists, Vulnerability.Affects[].Ref,
+    /// Annotation subjects) -- through a caller-supplied function.
+    /// </summary>
+    /// <remarks>
+    /// This generalizes traversal code CycloneDX.Utils.CycloneDXUtils.
+    /// HierarchicalMerge already hand-rolls for bom-ref namespacing (see
+    /// its private NamespaceComponentBomRefs/NamespaceDependencyBomRefs/
+    /// NamespaceCompositions/NamespaceVulnerabilitiesRefs/
+    /// NamespaceAnnotationsBomRefs methods) into one reusable entry point,
+    /// parameterized on an arbitrary rewrite function instead of always
+    /// prefixing a namespace. Namespacing becomes
+    /// <c>RewriteRefs(bom, r => $"{ns}:{r}")</c>; a manual single-ref
+    /// rename (as the CLI's <c>rename-entity</c> command needs) becomes
+    /// <c>RewriteRefs(bom, r => r == oldRef ? newRef : r)</c>.
+    ///
+    /// Scope note: covers Metadata.Component, Components, Services,
+    /// Dependencies, Compositions, Vulnerabilities, and Annotations -- it
+    /// does not yet walk the newer (CycloneDX 1.6) Declarations/Definitions
+    /// sections. Extending it there is a mechanical follow-up, not an
+    /// architectural one: add another block below following the same
+    /// pattern.
+    /// </remarks>
+    public static class BomRefWalker
+    {
+        public static void RewriteRefs(Bom bom, Func<string, string> rewrite)
+        {
+            if (bom is null || rewrite is null)
+            {
+                return;
+            }
+
+            if (bom.Metadata?.Component != null)
+            {
+                RewriteComponentTree(bom.Metadata.Component, rewrite);
+            }
+            if (bom.Metadata?.Tools?.Components != null)
+            {
+                foreach (var component in bom.Metadata.Tools.Components)
+                {
+                    RewriteComponentTree(component, rewrite);
+                }
+            }
+            if (bom.Metadata?.Tools?.Services != null)
+            {
+                foreach (var service in bom.Metadata.Tools.Services)
+                {
+                    service.BomRef = rewrite(service.BomRef);
+                }
+            }
+
+            if (bom.Components != null)
+            {
+                foreach (var component in bom.Components)
+                {
+                    RewriteComponentTree(component, rewrite);
+                }
+            }
+
+            if (bom.Services != null)
+            {
+                foreach (var service in bom.Services)
+                {
+                    service.BomRef = rewrite(service.BomRef);
+                }
+            }
+
+            if (bom.Dependencies != null)
+            {
+                RewriteDependencyTree(bom.Dependencies, rewrite);
+            }
+
+            if (bom.Compositions != null)
+            {
+                foreach (var composition in bom.Compositions)
+                {
+                    RewriteStringListInPlace(composition.Assemblies, rewrite);
+                    RewriteStringListInPlace(composition.Dependencies, rewrite);
+                }
+            }
+
+            if (bom.Vulnerabilities != null)
+            {
+                foreach (var vulnerability in bom.Vulnerabilities)
+                {
+                    vulnerability.BomRef = rewrite(vulnerability.BomRef);
+                    if (vulnerability.Affects != null)
+                    {
+                        foreach (var affect in vulnerability.Affects)
+                        {
+                            affect.Ref = rewrite(affect.Ref);
+                        }
+                    }
+                }
+            }
+
+            if (bom.Annotations != null)
+            {
+                foreach (var annotation in bom.Annotations)
+                {
+                    annotation.BomRef = rewrite(annotation.BomRef);
+                    if (annotation.XmlSubjects != null)
+                    {
+                        for (var i = 0; i < annotation.XmlSubjects.Count; i++)
+                        {
+                            annotation.XmlSubjects[i].Ref = rewrite(annotation.XmlSubjects[i].Ref);
+                        }
+                    }
+                    if (annotation.Annotator?.Component != null)
+                    {
+                        RewriteComponentTree(annotation.Annotator.Component, rewrite);
+                    }
+                    if (annotation.Annotator?.Individual != null)
+                    {
+                        annotation.Annotator.Individual.BomRef = rewrite(annotation.Annotator.Individual.BomRef);
+                    }
+                    if (annotation.Annotator?.Organization != null)
+                    {
+                        annotation.Annotator.Organization.BomRef = rewrite(annotation.Annotator.Organization.BomRef);
+                    }
+                    if (annotation.Annotator?.Service != null)
+                    {
+                        annotation.Annotator.Service.BomRef = rewrite(annotation.Annotator.Service.BomRef);
+                    }
+                }
+            }
+        }
+
+        private static void RewriteComponentTree(Component topComponent, Func<string, string> rewrite)
+        {
+            var pending = new Stack<Component>();
+            pending.Push(topComponent);
+            while (pending.Count > 0)
+            {
+                var component = pending.Pop();
+                if (component.Components != null)
+                {
+                    foreach (var sub in component.Components)
+                    {
+                        pending.Push(sub);
+                    }
+                }
+                component.BomRef = rewrite(component.BomRef);
+            }
+        }
+
+        private static void RewriteDependencyTree(List<Dependency> dependencies, Func<string, string> rewrite)
+        {
+            var pending = new Stack<Dependency>(dependencies);
+            while (pending.Count > 0)
+            {
+                var dependency = pending.Pop();
+                if (dependency.Dependencies != null)
+                {
+                    foreach (var sub in dependency.Dependencies)
+                    {
+                        pending.Push(sub);
+                    }
+                }
+                dependency.Ref = rewrite(dependency.Ref);
+            }
+        }
+
+        private static void RewriteStringListInPlace(List<string> refs, Func<string, string> rewrite)
+        {
+            if (refs is null)
+            {
+                return;
+            }
+            for (var i = 0; i < refs.Count; i++)
+            {
+                refs[i] = rewrite(refs[i]);
+            }
+        }
+    }
+}
+#endif

src/CycloneDX.Core/MergeableListHelper.cs

@@ -0,0 +1,127 @@
+// This file is part of CycloneDX Library for .NET
+//
+// 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
+// Copyright (c) OWASP Foundation. All Rights Reserved.
+
+#if NET8_0_OR_GREATER
+using System;
+using System.Collections.Generic;
+using CycloneDX.Models;
+
+namespace CycloneDX
+{
+    /// <summary>
+    /// Strategy-aware list merging for any element type implementing
+    /// IEquatable/IEquivalent/IMergeable. One generic method merges
+    /// List&lt;Hash&gt;, List&lt;Component&gt;, List&lt;OrganizationalContact&gt;,
+    /// etc., dispatching through real interface calls rather than a
+    /// separate reflection-driven helper per element type. Lives in
+    /// CycloneDX.Core (rather than alongside CycloneDX.Utils/Merge.cs)
+    /// specifically so model classes like Component can call it directly
+    /// from their own MergeWith implementations.
+    /// </summary>
+    public static class MergeableListHelper
+    {
+        public static List<T> Merge<T>(List<T> list1, List<T> list2, MergeStrategy strategy)
+            where T : IEquatable<T>, IEquivalent<T>, IMergeable<T>
+        {
+            if (list1 is null) return list2;
+            if (list2 is null) return list1;
+            if (strategy is null || !strategy.UseEntityMerge)
+            {
+                return ExactMatchMerge(list1, list2);
+            }
+
+            var result = new List<T>(list1);
+            foreach (var incoming in list2)
+            {
+                bool merged = false;
+                for (int i = 0; i < result.Count; i++)
+                {
+                    var existing = result[i];
+                    if (existing.Equals(incoming) || existing.Equivalent(incoming, strategy))
+                    {
+                        if (existing.MergeWith(incoming, strategy))
+                        {
+                            result[i] = existing;
+                            merged = true;
+                            break;
+                        }
+                    }
+                }
+                if (!merged)
+                {
+                    result.Add(incoming);
+                }
+            }
+            return result;
+        }
+
+        /// <summary>
+        /// Cheap fallback: dedupe by exact equality only, no MergeWith
+        /// attempts. Mirrors CycloneDX.Utils.ListMergeHelper&lt;T&gt;'s
+        /// behavior (kept independently here to avoid a Core-&gt;Utils
+        /// dependency, which would invert this project's reference graph).
+        /// </summary>
+        private static List<T> ExactMatchMerge<T>(List<T> list1, List<T> list2) where T : IEquatable<T>
+        {
+            var result = new List<T>(list1);
+            foreach (var item in list2)
+            {
+                bool found = false;
+                foreach (var existing in result)
+                {
+                    if (existing.Equals(item))
+                    {
+                        found = true;
+                        break;
+                    }
+                }
+                if (!found)
+                {
+                    result.Add(item);
+                }
+            }
+            return result;
+        }
+
+        /// <summary>Take whichever of two nullable reference values is non-null, preferring <paramref name="a"/>.</summary>
+        public static T MergeSingle<T>(T a, T b) where T : class => a ?? b;
+
+        /// <summary>Union two string lists, preserving order, dropping duplicates. Null if both are null.</summary>
+        public static List<string> MergeStringList(List<string> a, List<string> b)
+        {
+            if (a is null) return b;
+            if (b is null) return a;
+            var result = new List<string>(a);
+            foreach (var s in b)
+            {
+                if (!result.Contains(s))
+                {
+                    result.Add(s);
+                }
+            }
+            return result;
+        }
+
+        /// <summary>Nullable-bool "either says true" merge: null if both unset, else true if either is true.</summary>
+        public static bool? MergeNullableBoolOr(bool? a, bool? b)
+        {
+            if (!a.HasValue && !b.HasValue) return null;
+            return (a ?? false) || (b ?? false);
+        }
+    }
+}
+#endif

src/CycloneDX.Core/Models/Annotation.cs

@@ -26,6 +26,9 @@ namespace CycloneDX.Models
 {
     [ProtoContract]
     public class Annotation : IEquatable<Annotation>
+#if NET8_0_OR_GREATER
+        , IMergeable<Annotation>, IEquivalent<Annotation>
+#endif
     {
         [XmlType("subject")]
         public class XmlAnnotationSubject