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-rw-r--r--api/src/main/java/org/osjava/jardiff/Tools.java48
1 files changed, 44 insertions, 4 deletions
diff --git a/api/src/main/java/org/osjava/jardiff/Tools.java b/api/src/main/java/org/osjava/jardiff/Tools.java
index 7ac6a42..41ba63c 100644
--- a/api/src/main/java/org/osjava/jardiff/Tools.java
+++ b/api/src/main/java/org/osjava/jardiff/Tools.java
@@ -65,6 +65,18 @@ public final class Tools
return (value & mask) == 0;
}
+ private static boolean isLessAccessPermitted(int oldAccess, int newAccess) {
+ if (has(newAccess, Opcodes.ACC_PUBLIC)) {
+ return false;
+ } else if (has(newAccess, Opcodes.ACC_PROTECTED)) {
+ return has(oldAccess, Opcodes.ACC_PUBLIC);
+ } else if (has(newAccess, Opcodes.ACC_PRIVATE)) {
+ return not(oldAccess, Opcodes.ACC_PRIVATE);
+ } else {
+ return has(oldAccess, Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED);
+ }
+ }
+
/**
* @deprecated Use {@link #isClassAccessChange(int, int)}.
*/
@@ -118,6 +130,14 @@ public final class Tools
* Returns whether a field's newAccess is incompatible with oldAccess
* following <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html">Java Language Specification, Java SE 7 Edition</a>:
* <ul>
+ * <li><a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html#jls-13.4.9">13.4.7 Access to Members and Constructors</a><ul>
+ * <li>Changing the declared access of a member or constructor to permit less access
+ * <b>may break compatibility</b> with pre-existing binaries, causing a linkage error to be thrown when these binaries are resolved.
+ * </li>
+ * <li>The binary format is defined so that changing a member or constructor to be more accessible does not cause a
+ * linkage error when a subclass (already) defines a method to have less access.
+ * </li>
+ * </ul></li>
* <li><a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html#jls-13.4.9">13.4.9 final Fields and Constants</a><ul>
* <li>If a field that was not declared final is changed to be declared final,
* then it <b>can break compatibility</b> with pre-existing binaries that attempt to assign new values to the field.</li>
@@ -155,13 +175,19 @@ public final class Tools
* @return
*/
public static boolean isFieldAccessChange(final int oldAccess, final int newAccess) {
+ if (isLessAccessPermitted(oldAccess, newAccess)) {
+ return true; // 13.4.7
+ }
if ( not(oldAccess, Opcodes.ACC_FINAL) && has(newAccess, Opcodes.ACC_FINAL) ) {
return true; // 13.4.9 #1
} else {
final int compatibleChanges = Opcodes.ACC_FINAL | // 13.4.9 #2
Opcodes.ACC_TRANSIENT; // 13.4.11 #1
- final int oldAccess2 = oldAccess & ~compatibleChanges;
- final int newAccess2 = newAccess & ~compatibleChanges;
+ final int accessPermissions = Opcodes.ACC_PUBLIC |
+ Opcodes.ACC_PROTECTED |
+ Opcodes.ACC_PRIVATE;
+ final int oldAccess2 = oldAccess & ~compatibleChanges & ~accessPermissions;
+ final int newAccess2 = newAccess & ~compatibleChanges & ~accessPermissions;
return oldAccess2 != newAccess2;
}
}
@@ -170,6 +196,14 @@ public final class Tools
* Returns whether a method's newAccess is incompatible with oldAccess
* following <a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html">Java Language Specification, Java SE 7 Edition</a>:
* <ul>
+ * <li><a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html#jls-13.4.9">13.4.7 Access to Members and Constructors</a><ul>
+ * <li>Changing the declared access of a member or constructor to permit less access
+ * <b>may break compatibility</b> with pre-existing binaries, causing a linkage error to be thrown when these binaries are resolved.
+ * </li>
+ * <li>The binary format is defined so that changing a member or constructor to be more accessible does not cause a
+ * linkage error when a subclass (already) defines a method to have less access.
+ * </li>
+ * </ul></li>
* <li><a href="http://docs.oracle.com/javase/specs/jls/se7/html/jls-13.html#jls-13.4.16">13.4.16 abstract Methods</a><ul>
* <li>Changing a method that is declared abstract to no longer be declared abstract
* <b>does not break compatibility</b> with pre-existing binaries.</li>
@@ -210,6 +244,9 @@ public final class Tools
* @return
*/
public static boolean isMethodAccessChange(final int oldAccess, final int newAccess) {
+ if (isLessAccessPermitted(oldAccess, newAccess)) {
+ return true; // 13.4.7
+ }
if ( not(oldAccess, Opcodes.ACC_ABSTRACT) && has(newAccess, Opcodes.ACC_ABSTRACT) ) {
return true; // 13.4.16 #2
} else if ( not(oldAccess, Opcodes.ACC_FINAL) && not(oldAccess, Opcodes.ACC_STATIC) &&
@@ -220,8 +257,11 @@ public final class Tools
Opcodes.ACC_FINAL | // 13.4.17 #1
Opcodes.ACC_NATIVE | // 13.4.18 #1
Opcodes.ACC_SYNCHRONIZED; // 13.4.20 #1
- final int oldAccess2 = oldAccess & ~compatibleChanges;
- final int newAccess2 = newAccess & ~compatibleChanges;
+ final int accessPermissions = Opcodes.ACC_PUBLIC |
+ Opcodes.ACC_PROTECTED |
+ Opcodes.ACC_PRIVATE;
+ final int oldAccess2 = oldAccess & ~compatibleChanges & ~accessPermissions;
+ final int newAccess2 = newAccess & ~compatibleChanges & ~accessPermissions;
return oldAccess2 != newAccess2;
}
}