fix(ohos): 修复大于 2MB 图片在 Node-API 传输失败的问题

OpenHarmony Node-API 实现中，napi_create_buffer/napi_create_external_buffer
存在大于 2097152 字节（2MB）返回 napi_invalid_arg 的硬性限制。此前 read_part
和 read_part_async 返回 Buffer 类型，导致超过 2MB 的高清图片在跨语言调用阶段
直接报错被 ImageStore 吞掉返回 null。

改用 sys::napi_create_arraybuffer 直接在 JS 堆中分配 ArrayBuffer，
不受 2MB 外部 Buffer 大小限制，并补充超 2MB 切片读取单元测试。

Signed-off-by: donglua <dongluh@gmail.com>

Author: donglua

core/tests/package_cache.rs

@@ -90,6 +90,16 @@ fn read_part_enforces_media_part_limit() -> TestResult {
     Ok(())
 }
 
+#[test]
+fn read_part_succeeds_for_large_media_over_two_mib() -> TestResult {
+    // 3 MiB entry (simulating high-res image like image8.png which exceeds OpenHarmony Node-API 2 MiB Buffer threshold)
+    let archive = TempArchive::new_deflated_padded("image_3mb.png", 3 * 1024 * 1024)?;
+
+    let result = read_part(&archive.path, "image_3mb.png")?;
+    assert_eq!(result.len(), 3 * 1024 * 1024);
+    Ok(())
+}
+
 #[test]
 fn read_part_limited_allows_custom_limit() -> TestResult {
     let archive = TempArchive::new(&[("small.bin", b"0123456789")])?;

viewer-ohos/native/src/lib.rs

@@ -21,15 +21,38 @@ fn parse_path_to_json(path: &str) -> Result<String> {
     }
 }
 
-fn read_zip_part(path: &str, part: &str) -> Result<Buffer> {
+fn create_arraybuffer_from_vec(env: &Env, data: Vec<u8>) -> Result<ArrayBuffer<'static>> {
+    let mut raw_value = std::ptr::null_mut();
+    let mut data_ptr = std::ptr::null_mut();
+    let len = data.len();
+    let status = unsafe {
+        napi_ohos::sys::napi_create_arraybuffer(
+            env.raw(),
+            len,
+            &mut data_ptr,
+            &mut raw_value,
+        )
+    };
+    if status != napi_ohos::sys::Status::napi_ok {
+        return Err(Error::from_status(Status::from(status)));
+    }
+    if !data_ptr.is_null() && len > 0 {
+        unsafe {
+            std::ptr::copy_nonoverlapping(data.as_ptr(), data_ptr.cast(), len);
+        }
+    }
+    unsafe { ArrayBuffer::from_napi_value(env.raw(), raw_value) }
+}
+
+fn read_zip_part_bytes(path: &str, part: &str) -> Result<Vec<u8>> {
     let result = catch_unwind(AssertUnwindSafe(
         || -> std::result::Result<Vec<u8>, String> {
             jz_office_core::read_part(Path::new(path), part).map_err(|e| e.to_string())
         },
     ));
 
     match result {
-        Ok(Ok(data)) => Ok(Buffer::from(data)),
+        Ok(Ok(data)) => Ok(data),
         Ok(Err(error)) => Err(Error::from_reason(error)),
         Err(_) => Err(Error::from_reason(
             "Failed to read document part".to_owned(),
@@ -77,15 +100,15 @@ pub struct ReadPartTask {
 
 #[napi]
 impl Task for ReadPartTask {
-    type Output = Buffer;
-    type JsValue = Buffer;
+    type Output = Vec<u8>;
+    type JsValue = ArrayBuffer<'static>;
 
     fn compute(&mut self) -> Result<Self::Output> {
-        read_zip_part(&self.path, &self.part)
+        read_zip_part_bytes(&self.path, &self.part)
     }
 
-    fn resolve(&mut self, _env: Env, output: Self::Output) -> Result<Self::JsValue> {
-        Ok(output)
+    fn resolve(&mut self, env: Env, output: Self::Output) -> Result<Self::JsValue> {
+        create_arraybuffer_from_vec(&env, output)
     }
 }
 
@@ -101,8 +124,9 @@ pub fn read_part_async(
 
 /// 同步读取文档 ZIP 包内指定部件字节流
 #[napi]
-pub fn read_part(path: String, part: String) -> Result<Buffer> {
-    read_zip_part(&path, &part)
+pub fn read_part(env: Env, path: String, part: String) -> Result<ArrayBuffer<'static>> {
+    let bytes = read_zip_part_bytes(&path, &part)?;
+    create_arraybuffer_from_vec(&env, bytes)
 }
 
 /// 清除当前缓存的所有文档包及 ZIP 索引句柄

viewer-ohos/src/main/cpp/types/libjz_office_ohos/index.d.ts

@@ -39,6 +39,9 @@ export class AbortSignal {
 }
 
 
+/** 清除当前缓存的所有文档包及 ZIP 索引句柄 */
+export declare function clearCache(): void
+
 /** 同步解析接口（对齐 Android NativeCore.parse） */
 export declare function parse(path: string): string
 
@@ -51,7 +54,3 @@ export declare function readPart(path: string, part: string): ArrayBuffer
 /** 异步读取文档 ZIP 包内指定部件字节流（用于按需加载内嵌图片） */
 export declare function readPartAsync(path: string, part: string, abortSignal?: AbortSignal | undefined | null): Promise<ArrayBuffer>
 
-/** 清除当前缓存的所有文档包及 ZIP 索引句柄 */
-export declare function clearCache(): void
-
-