Hi Mandy,
On 7/2/19 7:20 PM, Mandy Chung wrote:
Webrev updated:
http://cr.openjdk.java.net/~mchung/jdk14/8173978/webrev.01/
I just skimmed across code and I think there's a little optimization
possible in VerifyAccess:
224 // cross-module access
225 // 1. refc is in different module from lookupModule, or
226 // 2. refc is in lookupModule and a different module
from prevLookupModule
227 Module prevLookupModule = prevLookupClass != null ?
prevLookupClass.getModule()
228 :
lookupModule;
229 assert refModule != lookupModule || refModule !=
prevLookupModule;
230 if (isModuleAccessible(refc, lookupModule,
prevLookupModule))
231 return true;
...instead of seting prevLookupModule to lookupModule in case
prevLookupClass is null (common case) causing double canRead and
isExported checks against the same module in isModuleAccessible() (for
positive outcome - the case where we want the check to be quick):
250 public static boolean isModuleAccessible(Class<?> refc,
Module m1, Module m2) {
251 Module refModule = refc.getModule();
252 assert refModule != m1 || refModule != m2;
253 int mods = getClassModifiers(refc);
254 if (isPublic(mods)) {
255 if (m1.canRead(refModule) && m2.canRead(refModule)) {
256 String pn = refc.getPackageName();
257
258 // refc is exported package to at least both m1 and m2
259 if (refModule.isExported(pn, m1) &&
refModule.isExported(pn, m2))
260 return true;
261 }
262 }
263 return false;
264 }
...you could set prevLookupModule to null if prevLookupClass is null:
Module prevLookupModule = prevLookupClass != null
?
prevLookupClass.getModule()
: null;
...and then check against null in isModuleAccessible():
public static boolean isModuleAccessible(Class<?> refc, Module m1,
Module m2) {
Module refModule = refc.getModule();
assert refModule != m1 || refModule != m2;
int mods = getClassModifiers(refc);
if (isPublic(mods)) {
if (m1.canRead(refModule) && (m2 == null ||
m2.canRead(refModule))) {
String pn = refc.getPackageName();
// refc is exported package to at least both m1 and m2
if (refModule.isExported(pn, m1) && (m2 == null ||
refModule.isExported(pn, m2)))
return true;
}
}
return false;
}
I think this would be faster since canRead and isExported are not trivial...
Regards, Peter
