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Test Info:
- Manifest: js/xpconnect/tests/unit/xpcshell.toml
/* Any copyright is dedicated to the Public Domain.
// XPCNativeSet stores its interface count in a uint16_t and always holds
// nsISupports in addition to the interfaces nsIClassInfo reports, so the
// longest list a JS-implemented nsIClassInfo may return is UINT16_MAX - 1.
const MAX_INTERFACES = 65534;
function registerClassInfo(uuid, interfaceCount) {
const classID = Components.ID(uuid);
const contractID = `@mozilla.org/test/classinfo/${uuid};1`;
const instance = {
QueryInterface: ChromeUtils.generateQI([
"nsIObserver",
"nsINamed",
"nsIClassInfo",
]),
interfaces: new Array(interfaceCount).fill(Ci.nsIObserver),
contractID,
classDescription: "test class info",
classID,
flags: 0,
name: "test class info",
observe() {},
};
Components.manager
.QueryInterface(Ci.nsIComponentRegistrar)
.registerFactory(classID, instance.classDescription, contractID, {
createInstance(iid) {
return instance.QueryInterface(iid);
},
});
return contractID;
}
add_task(function test_interface_count_above_maximum() {
const contractID = registerClassInfo(
"8c2f741c-25d4-4c55-b888-ee0bd8b71aee",
MAX_INTERFACES + 2
);
Assert.throws(
() => Cc[contractID].createInstance(Ci.nsIObserver),
/NS_ERROR_XPC_CANT_CREATE_WN/,
"a class info reporting more interfaces than a set can hold is rejected"
);
});
add_task(function test_interface_count_just_above_maximum() {
const contractID = registerClassInfo(
"27515a3a-c444-4e85-bb03-151cda827c82",
MAX_INTERFACES + 1
);
Assert.throws(
() => Cc[contractID].createInstance(Ci.nsIObserver),
/NS_ERROR_XPC_CANT_CREATE_WN/,
"the interface count that would wrap the set's uint16_t is rejected"
);
});
add_task(function test_interface_count_at_maximum() {
const contractID = registerClassInfo(
"dd84c4d0-7ee6-471b-8087-9b4100323f02",
MAX_INTERFACES
);
const instance = Cc[contractID].createInstance(Ci.nsIObserver);
Assert.ok(instance, "the largest set a class info can ask for is built");
Assert.throws(
() => instance.QueryInterface(Ci.nsINamed),
/NS_NOINTERFACE/,
"extending a full set is rejected instead of wrapping its count to zero"
);
});
add_task(function test_extending_a_set_below_the_maximum() {
const contractID = registerClassInfo(
"5be70ea4-d21a-4a4e-b949-85c78ffa0c81",
1
);
const instance = Cc[contractID].createInstance(Ci.nsIObserver);
Assert.ok(
instance.QueryInterface(Ci.nsINamed),
"extending a set below the limit still works"
);
});