Pay attention to string offset and count fields.
Strings can be represented as an offset and count inside a larger
character array. Pay attention to the offset and count fields when
getting the string value instead of returning the entire underlying
character array.
Bug: 23223379
Change-Id: Idc95870e33ede90b23deed9489c8c4796107f585
diff --git a/tools/ahat/README.txt b/tools/ahat/README.txt
index a8e3884..1083c2f 100644
--- a/tools/ahat/README.txt
+++ b/tools/ahat/README.txt
@@ -31,9 +31,6 @@
another) How about, always sort by name?
* For long strings, limit the string length shown in the summary view to
something reasonable. Say 50 chars, then add a "..." at the end.
- * For string summaries, if the string is an offset into a bigger byte array,
- make sure to show just the part that's in the bigger byte array, not the
- entire byte array.
* For HeapTable with single heap shown, the heap name isn't centered?
* Consistently document functions.
* Should help be part of an AhatHandler, that automatically gets the menu and
@@ -72,6 +69,8 @@
time.
* That we don't show the 'extra' column in the DominatedList if we are
showing all the instances.
+ * That InstanceUtils.asString properly takes into account "offset" and
+ "count" fields, if they are present.
Reported Issues:
* Request to be able to sort tables by size.
diff --git a/tools/ahat/src/InstanceUtils.java b/tools/ahat/src/InstanceUtils.java
index 7ee3ff2..10c1092 100644
--- a/tools/ahat/src/InstanceUtils.java
+++ b/tools/ahat/src/InstanceUtils.java
@@ -37,22 +37,6 @@
}
/**
- * Read the char[] value from an hprof Instance.
- * Returns null if the object can't be interpreted as a char[].
- */
- private static char[] asCharArray(Instance inst) {
- if (! (inst instanceof ArrayInstance)) {
- return null;
- }
-
- ArrayInstance array = (ArrayInstance) inst;
- if (array.getArrayType() != Type.CHAR) {
- return null;
- }
- return array.asCharArray(0, array.getValues().length);
- }
-
- /**
* Read the byte[] value from an hprof Instance.
* Returns null if the instance is not a byte array.
*/
@@ -82,8 +66,32 @@
if (!isInstanceOfClass(inst, "java.lang.String")) {
return null;
}
- char[] value = getCharArrayField(inst, "value");
- return (value == null) ? null : new String(value);
+
+ Object value = getField(inst, "value");
+ if (!(value instanceof ArrayInstance)) {
+ return null;
+ }
+
+ ArrayInstance chars = (ArrayInstance) value;
+ if (chars.getArrayType() != Type.CHAR) {
+ return null;
+ }
+
+ // TODO: When perflib provides a better way to get the length of the
+ // array, we should use that here.
+ int numChars = chars.getValues().length;
+ int count = getIntField(inst, "count", numChars);
+ int offset = getIntField(inst, "offset", 0);
+ int end = offset + count - 1;
+
+ if (count == 0) {
+ return "";
+ }
+
+ if (offset >= 0 && offset < numChars && end >= 0 && end < numChars) {
+ return new String(chars.asCharArray(offset, count));
+ }
+ return null;
}
/**
@@ -175,6 +183,15 @@
}
/**
+ * Read an int field of an instance, returning a default value if the field
+ * was not an int or could not be read.
+ */
+ private static int getIntField(Instance inst, String fieldName, int def) {
+ Integer value = getIntField(inst, fieldName);
+ return value == null ? def : value;
+ }
+
+ /**
* Read the given field from the given instance.
* The field is assumed to be a byte[] field.
* Returns null if the field value is null, not a byte[] or could not be read.
@@ -187,14 +204,6 @@
return asByteArray((Instance)value);
}
- private static char[] getCharArrayField(Instance inst, String fieldName) {
- Object value = getField(inst, fieldName);
- if (!(value instanceof Instance)) {
- return null;
- }
- return asCharArray((Instance)value);
- }
-
// Return the bitmap instance associated with this object, or null if there
// is none. This works for android.graphics.Bitmap instances and their
// underlying Byte[] instances.
