olm/javascript/olm_inbound_group_session.js

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/* The 'length' argument to Pointer_stringify doesn't work if the input includes
* characters >= 128; we therefore need to add a NULL character to all of our
* strings. This acts as a symbolic constant to help show what we're doing.
*/
var NULL_BYTE_PADDING_LENGTH = 1;
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function InboundGroupSession() {
var size = Module['_olm_inbound_group_session_size']();
this.buf = malloc(size);
this.ptr = Module['_olm_inbound_group_session'](this.buf);
}
function inbound_group_session_method(wrapped) {
return function() {
var result = wrapped.apply(this, arguments);
if (result === OLM_ERROR) {
var message = Pointer_stringify(
Module['_olm_inbound_group_session_last_error'](arguments[0])
);
throw new Error("OLM." + message);
}
return result;
}
}
InboundGroupSession.prototype['free'] = function() {
Module['_olm_clear_inbound_group_session'](this.ptr);
free(this.ptr);
}
InboundGroupSession.prototype['pickle'] = restore_stack(function(key) {
var key_array = array_from_string(key);
var pickle_length = inbound_group_session_method(
Module['_olm_pickle_inbound_group_session_length']
)(this.ptr);
var key_buffer = stack(key_array);
var pickle_buffer = stack(pickle_length + NULL_BYTE_PADDING_LENGTH);
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inbound_group_session_method(Module['_olm_pickle_inbound_group_session'])(
this.ptr, key_buffer, key_array.length, pickle_buffer, pickle_length
);
return Pointer_stringify(pickle_buffer);
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});
InboundGroupSession.prototype['unpickle'] = restore_stack(function(key, pickle) {
var key_array = array_from_string(key);
var key_buffer = stack(key_array);
var pickle_array = array_from_string(pickle);
var pickle_buffer = stack(pickle_array);
inbound_group_session_method(Module['_olm_unpickle_inbound_group_session'])(
this.ptr, key_buffer, key_array.length, pickle_buffer,
pickle_array.length
);
});
InboundGroupSession.prototype['create'] = restore_stack(function(session_key) {
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var key_array = array_from_string(session_key);
var key_buffer = stack(key_array);
inbound_group_session_method(Module['_olm_init_inbound_group_session'])(
this.ptr, key_buffer, key_array.length
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);
});
InboundGroupSession.prototype['decrypt'] = restore_stack(function(
message
) {
var message_buffer, plaintext_buffer, plaintext_length;
try {
message_buffer = malloc(message.length);
Module['writeAsciiToMemory'](message, message_buffer, true);
var max_plaintext_length = inbound_group_session_method(
Module['_olm_group_decrypt_max_plaintext_length']
)(this.ptr, message_buffer, message.length);
// caculating the length destroys the input buffer, so we need to re-copy it.
Module['writeAsciiToMemory'](message, message_buffer, true);
plaintext_buffer = malloc(max_plaintext_length + NULL_BYTE_PADDING_LENGTH);
var message_index = stack(4);
plaintext_length = inbound_group_session_method(
Module["_olm_group_decrypt"]
)(
this.ptr,
message_buffer, message.length,
plaintext_buffer, max_plaintext_length,
message_index
);
// UTF8ToString requires a null-terminated argument, so add the
// null terminator.
Module['setValue'](
plaintext_buffer+plaintext_length,
0, "i8"
);
return {
"plaintext": UTF8ToString(plaintext_buffer),
"message_index": Module['getValue'](message_index, "i32")
}
} finally {
if (message_buffer !== undefined) {
free(message_buffer);
}
if (plaintext_buffer !== undefined) {
// don't leave a copy of the plaintext in the heap.
bzero(plaintext_buffer, plaintext_length + NULL_BYTE_PADDING_LENGTH);
free(plaintext_buffer);
}
}
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});
InboundGroupSession.prototype['session_id'] = restore_stack(function() {
var length = inbound_group_session_method(
Module['_olm_inbound_group_session_id_length']
)(this.ptr);
var session_id = stack(length + NULL_BYTE_PADDING_LENGTH);
inbound_group_session_method(Module['_olm_inbound_group_session_id'])(
this.ptr, session_id, length
);
return Pointer_stringify(session_id);
});
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olm_exports['InboundGroupSession'] = InboundGroupSession;