[Firebase AI] Change public fields to easier types (#1290)

* [Firebase AI] Change public fields to easier types

* Update ModelContent.cs

Author: a-maurice

docs/readme.md

@@ -123,6 +123,8 @@ Release Notes
     - Firebase AI: Add support for defining a Thinking budget.
     - Firebase AI: Deprecated `CountTokensResponse.TotalBillableCharacters`, use
       `CountTokensResponse.TotalTokens` instead.
+    - Firebase AI: Changed public field types for ReadOnlyMemory<byte> to byte[],
+      and IEnumerable to IReadOnlyList.
     - Messaging: Removed deprecated `FirebaseMessage.Dispose`,
       `FirebaseNotification.Dispose`, and `MessagingOptions.Dispose` methods.
 

firebaseai/src/Candidate.cs

@@ -14,10 +14,7 @@
  * limitations under the License.
  */
 
-using System;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
-using System.Linq;
 using Firebase.AI.Internal;
 
 namespace Firebase.AI {
@@ -73,7 +70,7 @@ public enum FinishReason {
 /// Each content generation prompt may produce multiple candidate responses.
 /// </summary>
 public readonly struct Candidate {
-  private readonly ReadOnlyCollection<SafetyRating> _safetyRatings;
+  private readonly IReadOnlyList<SafetyRating> _safetyRatings;
 
   /// <summary>
   /// The response’s content.
@@ -83,9 +80,9 @@ public readonly struct Candidate {
   /// <summary>
   /// The safety rating of the response content.
   /// </summary>
-  public IEnumerable<SafetyRating> SafetyRatings {
+  public IReadOnlyList<SafetyRating> SafetyRatings {
     get {
-      return _safetyRatings ?? new ReadOnlyCollection<SafetyRating>(new List<SafetyRating>());
+      return _safetyRatings ?? new List<SafetyRating>();
     }
   }
 
@@ -110,7 +107,7 @@ private Candidate(ModelContent content, List<SafetyRating> safetyRatings,
       FinishReason? finishReason, CitationMetadata? citationMetadata,
       GroundingMetadata? groundingMetadata) {
     Content = content;
-    _safetyRatings = new ReadOnlyCollection<SafetyRating>(safetyRatings ?? new List<SafetyRating>());
+    _safetyRatings = safetyRatings ?? new List<SafetyRating>();
     FinishReason = finishReason;
     CitationMetadata = citationMetadata;
     GroundingMetadata = groundingMetadata;

firebaseai/src/Chat.cs

@@ -15,7 +15,6 @@
  */
 
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading;
@@ -36,11 +35,7 @@ public class Chat {
   /// The previous content from the chat that has been successfully sent and received from the
   /// model. This will be provided to the model for each message sent as context for the discussion.
   /// </summary>
-  public IEnumerable<ModelContent> History {
-    get {
-     return new ReadOnlyCollection<ModelContent>(chatHistory);
-    }
-  }
+  public IReadOnlyList<ModelContent> History => chatHistory;
 
   // Note: No public constructor, get one through GenerativeModel.StartChat
   private Chat(GenerativeModel model, IEnumerable<ModelContent> initialHistory) {

firebaseai/src/Citation.cs

@@ -16,7 +16,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using Firebase.AI.Internal;
 
 namespace Firebase.AI {
@@ -25,20 +24,20 @@ namespace Firebase.AI {
 /// A collection of source attributions for a piece of content.
 /// </summary>
 public readonly struct CitationMetadata {
-  private readonly ReadOnlyCollection<Citation> _citations;
+  private readonly IReadOnlyList<Citation> _citations;
 
   /// <summary>
   /// A list of individual cited sources and the parts of the content to which they apply.
   /// </summary>
-  public IEnumerable<Citation> Citations {
+  public IReadOnlyList<Citation> Citations {
     get {
-      return _citations ?? new ReadOnlyCollection<Citation>(new List<Citation>());
+      return _citations ?? new List<Citation>();
     }
   }
 
   // Hidden constructor, users don't need to make this.
   private CitationMetadata(List<Citation> citations) {
-    _citations = new ReadOnlyCollection<Citation>(citations ?? new List<Citation>());
+    _citations = citations;
   }
 
   /// <summary>

firebaseai/src/CountTokensResponse.cs

@@ -16,7 +16,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using Google.MiniJSON;
 using Firebase.AI.Internal;
 
@@ -44,13 +43,13 @@ public readonly struct CountTokensResponse {
   [Obsolete("Use TotalTokens instead; Gemini 2.0 series models and newer are always billed by token count.")]
   public int? TotalBillableCharacters { get; }
 
-  private readonly ReadOnlyCollection<ModalityTokenCount> _promptTokensDetails;
+  private readonly IReadOnlyList<ModalityTokenCount> _promptTokensDetails;
   /// <summary>
   /// The breakdown, by modality, of how many tokens are consumed by the prompt.
   /// </summary>
-  public IEnumerable<ModalityTokenCount> PromptTokensDetails {
+  public IReadOnlyList<ModalityTokenCount> PromptTokensDetails {
     get {
-      return _promptTokensDetails ?? new ReadOnlyCollection<ModalityTokenCount>(new List<ModalityTokenCount>());
+      return _promptTokensDetails ?? new List<ModalityTokenCount>();
     }
   }
 
@@ -62,8 +61,7 @@ private CountTokensResponse(int totalTokens,
 #pragma warning disable CS0618
     TotalBillableCharacters = totalBillableCharacters;
 #pragma warning restore CS0618
-    _promptTokensDetails =
-        new ReadOnlyCollection<ModalityTokenCount>(promptTokensDetails ?? new List<ModalityTokenCount>());
+    _promptTokensDetails = promptTokensDetails;
   }
 
   /// <summary>

firebaseai/src/GenerateContentResponse.cs

@@ -16,7 +16,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Collections.ObjectModel;
 using System.Linq;
 using Google.MiniJSON;
 using Firebase.AI.Internal;
@@ -27,14 +26,14 @@ namespace Firebase.AI {
 /// The model's response to a generate content request.
 /// </summary>
 public readonly struct GenerateContentResponse {
-  private readonly ReadOnlyCollection<Candidate> _candidates;
+  private readonly IReadOnlyList<Candidate> _candidates;
 
   /// <summary>
   /// A list of candidate response content, ordered from best to worst.
   /// </summary>
-  public IEnumerable<Candidate> Candidates {
+  public IReadOnlyList<Candidate> Candidates {
     get {
-      return _candidates ?? new ReadOnlyCollection<Candidate>(new List<Candidate>());
+      return _candidates ?? new List<Candidate>();
     }
   }
 
@@ -64,16 +63,16 @@ public string Text {
   /// <summary>
   /// Returns function calls found in any `Part`s of the first candidate of the response, if any.
   /// </summary>
-  public IEnumerable<ModelContent.FunctionCallPart> FunctionCalls {
+  public IReadOnlyList<ModelContent.FunctionCallPart> FunctionCalls {
     get {
-      return Candidates.FirstOrDefault().Content.Parts.OfType<ModelContent.FunctionCallPart>();
+      return Candidates.FirstOrDefault().Content.Parts.OfType<ModelContent.FunctionCallPart>().ToList();
     }
   }
 
   // Hidden constructor, users don't need to make this.
   private GenerateContentResponse(List<Candidate> candidates, PromptFeedback? promptFeedback,
       UsageMetadata? usageMetadata) {
-    _candidates = new ReadOnlyCollection<Candidate>(candidates ?? new List<Candidate>());
+    _candidates = candidates;
     PromptFeedback = promptFeedback;
     UsageMetadata = usageMetadata;
   }
@@ -132,7 +131,7 @@ public enum BlockReason {
 /// A metadata struct containing any feedback the model had on the prompt it was provided.
 /// </summary>
 public readonly struct PromptFeedback {
-  private readonly ReadOnlyCollection<SafetyRating> _safetyRatings;
+  private readonly IReadOnlyList<SafetyRating> _safetyRatings;
 
   /// <summary>
   /// The reason a prompt was blocked, if it was blocked.
@@ -145,9 +144,9 @@ public readonly struct PromptFeedback {
   /// <summary>
   /// The safety ratings of the prompt.
   /// </summary>
-  public IEnumerable<SafetyRating> SafetyRatings {
+  public IReadOnlyList<SafetyRating> SafetyRatings {
     get {
-      return _safetyRatings ?? new ReadOnlyCollection<SafetyRating>(new List<SafetyRating>());
+      return _safetyRatings ?? new List<SafetyRating>();
     }
   }
 
@@ -156,7 +155,7 @@ private PromptFeedback(BlockReason? blockReason, string blockReasonMessage,
                          List<SafetyRating> safetyRatings) {
     BlockReason = blockReason;
     BlockReasonMessage = blockReasonMessage;
-    _safetyRatings = new ReadOnlyCollection<SafetyRating>(safetyRatings ?? new List<SafetyRating>());
+    _safetyRatings = safetyRatings;
   }
 
   private static BlockReason ParseBlockReason(string str) {
@@ -191,37 +190,37 @@ internal static PromptFeedback FromJson(Dictionary<string, object> jsonDict) {
 /// section within the Service Specific Terms).
 /// </summary>
 public readonly struct GroundingMetadata {
-  private readonly ReadOnlyCollection<string> _webSearchQueries;
-  private readonly ReadOnlyCollection<GroundingChunk> _groundingChunks;
-  private readonly ReadOnlyCollection<GroundingSupport> _groundingSupports;
+  private readonly IReadOnlyList<string> _webSearchQueries;
+  private readonly IReadOnlyList<GroundingChunk> _groundingChunks;
+  private readonly IReadOnlyList<GroundingSupport> _groundingSupports;
 
   /// <summary>
   /// A list of web search queries that the model performed to gather the grounding information.
   /// These can be used to allow users to explore the search results themselves.
   /// </summary>
-  public IEnumerable<string> WebSearchQueries {
+  public IReadOnlyList<string> WebSearchQueries {
     get {
-      return _webSearchQueries ?? new ReadOnlyCollection<string>(new List<string>());
+      return _webSearchQueries ?? new List<string>();
     }
   }
 
   /// <summary>
   /// A list of `GroundingChunk` structs. Each chunk represents a piece of retrieved content
   /// (e.g., from a web page) that the model used to ground its response.
   /// </summary>
-  public IEnumerable<GroundingChunk> GroundingChunks {
+  public IReadOnlyList<GroundingChunk> GroundingChunks {
     get {
-      return _groundingChunks ?? new ReadOnlyCollection<GroundingChunk>(new List<GroundingChunk>());
+      return _groundingChunks ?? new List<GroundingChunk>();
     }
   }
 
   /// <summary>
   /// A list of `GroundingSupport` structs. Each object details how specific segments of the
   /// model's response are supported by the `groundingChunks`.
   /// </summary>
-  public IEnumerable<GroundingSupport> GroundingSupports {
+  public IReadOnlyList<GroundingSupport> GroundingSupports {
     get {
-      return _groundingSupports ?? new ReadOnlyCollection<GroundingSupport>(new List<GroundingSupport>());
+      return _groundingSupports ?? new List<GroundingSupport>();
     }
   }
 
@@ -234,9 +233,9 @@ public IEnumerable<GroundingSupport> GroundingSupports {
 
   private GroundingMetadata(List<string> webSearchQueries, List<GroundingChunk> groundingChunks,
                             List<GroundingSupport> groundingSupports, SearchEntryPoint? searchEntryPoint) {
-    _webSearchQueries = new ReadOnlyCollection<string>(webSearchQueries ?? new List<string>());
-    _groundingChunks = new ReadOnlyCollection<GroundingChunk>(groundingChunks ?? new List<GroundingChunk>());
-    _groundingSupports = new ReadOnlyCollection<GroundingSupport>(groundingSupports ?? new List<GroundingSupport>());
+    _webSearchQueries = webSearchQueries;
+    _groundingChunks = groundingChunks;
+    _groundingSupports = groundingSupports;
     SearchEntryPoint = searchEntryPoint;
   }
 
@@ -347,7 +346,7 @@ internal static WebGroundingChunk FromJson(Dictionary<string, object> jsonDict)
 /// retrieved grounding chunks.
 /// </summary>
 public readonly struct GroundingSupport {
-  private readonly ReadOnlyCollection<int> _groundingChunkIndices;
+  private readonly IReadOnlyList<int> _groundingChunkIndices;
 
   /// <summary>
   /// Specifies the segment of the model's response content that this grounding support pertains
@@ -363,15 +362,15 @@ public readonly struct GroundingSupport {
   /// means that `groundingChunks[1]`, `groundingChunks[3]`, `groundingChunks[4]` are the
   /// retrieved content supporting this part of the response.
   /// </summary>
-  public IEnumerable<int> GroundingChunkIndices {
+  public IReadOnlyList<int> GroundingChunkIndices {
     get {
-      return _groundingChunkIndices ?? new ReadOnlyCollection<int>(new List<int>());
+      return _groundingChunkIndices ?? new List<int>();
     }
   }
 
   private GroundingSupport(Segment segment, List<int> groundingChunkIndices) {
     Segment = segment;
-    _groundingChunkIndices = new ReadOnlyCollection<int>(groundingChunkIndices ?? new List<int>());
+    _groundingChunkIndices = groundingChunkIndices;
   }
 
   internal static GroundingSupport FromJson(Dictionary<string, object> jsonDict) {
@@ -459,17 +458,17 @@ public readonly struct UsageMetadata {
   /// </summary>
   public int TotalTokenCount { get; }
 
-  private readonly ReadOnlyCollection<ModalityTokenCount> _promptTokensDetails;
-  public IEnumerable<ModalityTokenCount> PromptTokensDetails {
+  private readonly IReadOnlyList<ModalityTokenCount> _promptTokensDetails;
+  public IReadOnlyList<ModalityTokenCount> PromptTokensDetails {
     get {
-      return _promptTokensDetails ?? new ReadOnlyCollection<ModalityTokenCount>(new List<ModalityTokenCount>());
+      return _promptTokensDetails ?? new List<ModalityTokenCount>();
     }
   }
 
-  private readonly ReadOnlyCollection<ModalityTokenCount> _candidatesTokensDetails;
-  public IEnumerable<ModalityTokenCount> CandidatesTokensDetails {
+  private readonly IReadOnlyList<ModalityTokenCount> _candidatesTokensDetails;
+  public IReadOnlyList<ModalityTokenCount> CandidatesTokensDetails {
     get {
-      return _candidatesTokensDetails ?? new ReadOnlyCollection<ModalityTokenCount>(new List<ModalityTokenCount>());
+      return _candidatesTokensDetails ?? new List<ModalityTokenCount>();
     }
   }
 
@@ -480,11 +479,8 @@ private UsageMetadata(int promptTC, int candidatesTC, int thoughtsTC, int totalT
     CandidatesTokenCount = candidatesTC;
     ThoughtsTokenCount = thoughtsTC;
     TotalTokenCount = totalTC;
-    _promptTokensDetails =
-        new ReadOnlyCollection<ModalityTokenCount>(promptDetails ?? new List<ModalityTokenCount>());
-    _candidatesTokensDetails =
-        new ReadOnlyCollection<ModalityTokenCount>(candidateDetails ?? new List<ModalityTokenCount>());
-
+    _promptTokensDetails = promptDetails;
+    _candidatesTokensDetails = candidateDetails;
   }
 
   /// <summary>