Adding upstream version 0.0~git20250520.a1d9079+dfsg.

Signed-off-by: Daniel Baumann <daniel@debian.org>

asset/asset_android.go

@@ -0,0 +1,109 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package asset
+
+/*
+#cgo LDFLAGS: -landroid
+#include <android/asset_manager.h>
+#include <android/asset_manager_jni.h>
+#include <jni.h>
+#include <stdlib.h>
+
+static AAssetManager* asset_manager_init(uintptr_t java_vm, uintptr_t jni_env, jobject ctx) {
+	JavaVM* vm = (JavaVM*)java_vm;
+	JNIEnv* env = (JNIEnv*)jni_env;
+
+	// Equivalent to:
+	//	assetManager = ctx.getResources().getAssets();
+	jclass ctx_clazz = (*env)->FindClass(env, "android/content/Context");
+	jmethodID getres_id = (*env)->GetMethodID(env, ctx_clazz, "getResources", "()Landroid/content/res/Resources;");
+	jobject res = (*env)->CallObjectMethod(env, ctx, getres_id);
+	jclass res_clazz = (*env)->FindClass(env, "android/content/res/Resources");
+	jmethodID getam_id = (*env)->GetMethodID(env, res_clazz, "getAssets", "()Landroid/content/res/AssetManager;");
+	jobject am = (*env)->CallObjectMethod(env, res, getam_id);
+
+	// Pin the AssetManager and load an AAssetManager from it.
+	am = (*env)->NewGlobalRef(env, am);
+	return AAssetManager_fromJava(env, am);
+}
+*/
+import "C"
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"sync"
+	"unsafe"
+
+	"golang.org/x/mobile/internal/mobileinit"
+)
+
+var assetOnce sync.Once
+
+// asset_manager is the asset manager of the app.
+var assetManager *C.AAssetManager
+
+func assetInit() {
+	err := mobileinit.RunOnJVM(func(vm, env, ctx uintptr) error {
+		assetManager = C.asset_manager_init(C.uintptr_t(vm), C.uintptr_t(env), C.jobject(ctx))
+		return nil
+	})
+	if err != nil {
+		log.Fatalf("asset: %v", err)
+	}
+}
+
+func openAsset(name string) (File, error) {
+	assetOnce.Do(assetInit)
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	a := &asset{
+		ptr:  C.AAssetManager_open(assetManager, cname, C.AASSET_MODE_UNKNOWN),
+		name: name,
+	}
+	if a.ptr == nil {
+		return nil, a.errorf("open", "bad asset")
+	}
+	return a, nil
+}
+
+type asset struct {
+	ptr  *C.AAsset
+	name string
+}
+
+func (a *asset) errorf(op string, format string, v ...interface{}) error {
+	return &os.PathError{
+		Op:   op,
+		Path: a.name,
+		Err:  fmt.Errorf(format, v...),
+	}
+}
+
+func (a *asset) Read(p []byte) (n int, err error) {
+	n = int(C.AAsset_read(a.ptr, unsafe.Pointer(&p[0]), C.size_t(len(p))))
+	if n == 0 && len(p) > 0 {
+		return 0, io.EOF
+	}
+	if n < 0 {
+		return 0, a.errorf("read", "negative bytes: %d", n)
+	}
+	return n, nil
+}
+
+func (a *asset) Seek(offset int64, whence int) (int64, error) {
+	// TODO(crawshaw): use AAsset_seek64 if it is available.
+	off := C.AAsset_seek(a.ptr, C.off_t(offset), C.int(whence))
+	if off == -1 {
+		return 0, a.errorf("seek", "bad result for offset=%d, whence=%d", offset, whence)
+	}
+	return int64(off), nil
+}
+
+func (a *asset) Close() error {
+	C.AAsset_close(a.ptr)
+	return nil
+}