feat(jni): add getRimeCandidates API

Author: WhiredPlanck

app/src/main/java/com/osfans/trime/core/Rime.kt

@@ -109,6 +109,14 @@ class Rime : RimeApi, RimeLifecycleOwner {
             getRimeOption(option)
         }
 
+    override suspend fun getCandidates(
+        startIndex: Int,
+        limit: Int,
+    ): Array<CandidateListItem> =
+        withRimeContext {
+            getRimeCandidates(startIndex, limit) ?: emptyArray()
+        }
+
     private fun handleRimeNotification(notif: RimeNotification<*>) {
         when (notif) {
             is RimeNotification.SchemaNotification -> schemaItemCached = notif.value
@@ -454,6 +462,12 @@ class Rime : RimeApi, RimeLifecycleOwner {
             state: Boolean,
         ): String?
 
+        @JvmStatic
+        external fun getRimeCandidates(
+            startIndex: Int,
+            limit: Int,
+        ): Array<CandidateListItem>?
+
         /** call from rime_jni */
         @JvmStatic
         fun handleRimeNotification(

app/src/main/java/com/osfans/trime/core/RimeApi.kt

@@ -41,4 +41,9 @@ interface RimeApi {
     )
 
     suspend fun getRuntimeOption(option: String): Boolean
+
+    suspend fun getCandidates(
+        startIndex: Int,
+        limit: Int,
+    ): Array<CandidateListItem>
 }

app/src/main/jni/librime_jni/rime_jni.cc

@@ -5,6 +5,7 @@
 #include <rime_api.h>
 
 #include <string>
+#include <vector>
 
 #include "jni-utils.h"
 #include "objconv.h"
@@ -117,6 +118,31 @@ class Rime {
     return rime->get_state_label(session, optionName.c_str(), state);
   }
 
+  using CandidateItem = std::pair<std::string, std::string>;
+  using CandidateList = std::vector<CandidateItem>;
+
+  CandidateList getCandidates(int startIndex, int limit) {
+    CandidateList result;
+    result.reserve(limit);
+    RimeCandidateListIterator iter{nullptr};
+    if (rime->candidate_list_from_index(session, &iter, startIndex)) {
+      int count = 0;
+      while (rime->candidate_list_next(&iter)) {
+        if (count >= limit) break;
+        std::string text(iter.candidate.text);
+        std::string comment;
+        if (iter.candidate.comment) {
+          comment = iter.candidate.comment;
+        }
+        auto item = std::make_pair(text, comment);
+        result.emplace_back(std::move(item));
+        ++count;
+      }
+      rime->candidate_list_end(&iter);
+    }
+    return std::move(result);
+  }
+
   void exit() {
     rime->destroy_session(session);
     session = 0;
@@ -480,3 +506,25 @@ Java_com_osfans_trime_core_Rime_getRimeStateLabel(JNIEnv *env,
   return env->NewStringUTF(
       Rime::Instance().stateLabel(CString(env, option_name), state).c_str());
 }
+
+extern "C" JNIEXPORT jobjectArray JNICALL
+Java_com_osfans_trime_core_Rime_getRimeCandidates(JNIEnv *env, jclass clazz,
+                                                  jint start_index,
+                                                  jint limit) {
+  if (!is_rime_running()) {
+    return nullptr;
+  }
+  auto candidates = Rime::Instance().getCandidates(start_index, limit);
+  int size = static_cast<int>(candidates.size());
+  jobjectArray array =
+      env->NewObjectArray(size, GlobalRef->CandidateListItem, nullptr);
+  for (int i = 0; i < size; i++) {
+    auto &candidate = candidates[i];
+    auto item = JRef<>(env, env->NewObject(GlobalRef->CandidateListItem,
+                                           GlobalRef->CandidateListItemInit,
+                                           *JString(env, candidate.second),
+                                           *JString(env, candidate.first)));
+    env->SetObjectArrayElement(array, i, item);
+  }
+  return array;
+}