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Use more stable fields for ART class spec offset detection #362

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Merged
oleavr merged 1 commit into from
Jul 24, 2025
Merged

Use more stable fields for ART class spec offset detection #362

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20 changes: 10 additions & 10 deletions lib/android.js
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Original file line number Diff line number Diff line change
Expand Up @@ -967,14 +967,14 @@ export function getArtClassSpec (vm) {
const fInfo = {
artArrayLengthSize: 4,
artArrayEntrySize: fieldSpec.size,
// java/io/File has 15 fields on Android 16.
artArrayMax: 25
// java/lang/Thread has 36 fields on Android 16.
artArrayMax: 50
};

const mInfo = {
artArrayLengthSize: pointerSize,
artArrayEntrySize: methodSpec.size,
// java/io/File has 63 methods on Android 16.
// java/lang/Thread has 79 methods on Android 16.
artArrayMax: 100
};

Expand Down Expand Up @@ -1015,7 +1015,7 @@ export function getArtClassSpec (vm) {
return false;
};

const clazz = env.findClass('java/io/File');
const clazz = env.findClass('java/lang/Thread');
const clazzRef = env.newGlobalRef(clazz);

try {
Expand All @@ -1024,8 +1024,8 @@ export function getArtClassSpec (vm) {
object = getApi()['art::JavaVMExt::DecodeGlobal'](vm, thread, clazzRef);
});

const fieldInstance = env.getFieldId(clazzRef, 'path', 'Ljava/lang/String;');
const fieldStatic = env.getStaticFieldId(clazzRef, 'separatorChar', 'C');
const fieldInstance = env.getFieldId(clazzRef, 'name', 'Ljava/lang/String;');
const fieldStatic = env.getStaticFieldId(clazzRef, 'MAX_PRIORITY', 'I');

let offsetStatic = -1;
let offsetInstance = -1;
Expand All @@ -1038,20 +1038,20 @@ export function getArtClassSpec (vm) {
}
}
if (offsetInstance === -1 || offsetStatic === -1) {
throw new Error('Unable to find fields in java/io/File; please file a bug');
throw new Error('Unable to find fields in java/lang/Thread; please file a bug');
}
const sfieldOffset = (offsetInstance !== offsetStatic) ? offsetStatic : 0;
const ifieldOffset = offsetInstance;

let offsetMethods = -1;
const methodInstance = env.getMethodId(clazzRef, 'length', '()J');
const methodInstance = env.getMethodId(clazzRef, 'getName', '()Ljava/lang/String;');
for (let offset = 0; offset !== MAX_OFFSET; offset += 4) {
if (offsetMethods === -1 && hasEntry(object, offset, methodInstance, mInfo)) {
offsetMethods = offset;
}
}
if (offsetMethods === -1) {
throw new Error('Unable to find methods in java/io/File; please file a bug');
throw new Error('Unable to find methods in java/lang/Thread; please file a bug');
}

let offsetCopiedMethods = -1;
Expand All @@ -1064,7 +1064,7 @@ export function getArtClassSpec (vm) {
}
}
if (offsetCopiedMethods === -1) {
throw new Error('Unable to find copied methods in java/io/File; please file a bug');
throw new Error('Unable to find copied methods in java/lang/Thread; please file a bug');
}

spec = {
Expand Down
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