Revision: 5622
Author: [email protected]
Date: Thu Oct 14 05:54:00 2010
Log: Restructure RegExp exec cache code.
Review URL: http://codereview.chromium.org/3778004
http://code.google.com/p/v8/source/detail?r=5622
Modified:
/branches/bleeding_edge/src/regexp.js
/branches/bleeding_edge/src/string.js
/branches/bleeding_edge/test/mjsunit/regexp.js
=======================================
--- /branches/bleeding_edge/src/regexp.js Thu Oct 14 01:51:20 2010
+++ /branches/bleeding_edge/src/regexp.js Thu Oct 14 05:54:00 2010
@@ -126,11 +126,11 @@
this.regExp = 0;
this.subject = 0;
this.replaceString = 0;
- this.lastIndex = 0; // Also used for splitLimit when type is "split"
this.answer = 0;
// answerSaved marks whether the contents of answer is valid for a cache
// hit in RegExpExec, StringMatch and StringSplit.
this.answerSaved = false;
+ this.splitLimit = 0; // Used only when type is "split".
}
@@ -181,22 +181,30 @@
var cache = regExpCache;
var saveAnswer = false;
+ var lastIndex = this.lastIndex;
+
+ // Since cache.subject is always a string, a matching input can not
+ // cause visible side-effects when converted to a string, so we can omit
+ // the conversion required by the specification.
+ // Likewise, the regexp.lastIndex and regexp.global properties are value
+ // properties that are not configurable, so reading them can also not
cause
+ // any side effects (converting lastIndex to a number can, though).
if (%_ObjectEquals(cache.type, 'exec') &&
- %_ObjectEquals(cache.lastIndex, this.lastIndex) &&
+ %_ObjectEquals(0, lastIndex) &&
%_IsRegExpEquivalent(cache.regExp, this) &&
%_ObjectEquals(cache.subject, string)) {
if (cache.answerSaved) {
- // If this regexp is global, cache.lastIndex is zero, so we only get
- // here if this.lastIndex is zero, and resulting this.lastIndex
- // must be zero too, so no change is necessary.
- if (!this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
+ // The regexp.lastIndex value must be 0 for non-global RegExps, and
for
+ // global RegExps we only cache negative results, which gives a
lastIndex
+ // of zero as well.
+ this.lastIndex = 0;
return %_RegExpCloneResult(cache.answer);
} else {
saveAnswer = true;
}
}
- if (%_ArgumentsLength() == 0) {
+ if (%_ArgumentsLength() === 0) {
var regExpInput = LAST_INPUT(lastMatchInfo);
if (IS_UNDEFINED(regExpInput)) {
throw MakeError('no_input_to_regexp', [this]);
@@ -209,41 +217,48 @@
} else {
s = ToString(string);
}
- var lastIndex = this.lastIndex;
-
- var i = this.global ? TO_INTEGER(lastIndex) : 0;
-
- if (i < 0 || i > s.length) {
- this.lastIndex = 0;
- return null;
+ var global = this.global;
+
+ // Conversion is required by the ES5 specification (RegExp.prototype.exec
+ // algorithm, step 5) even if the value is discarded for non-global
RegExps.
+ var i = TO_INTEGER(lastIndex);
+ if (global) {
+ if (i < 0 || i > s.length) {
+ this.lastIndex = 0;
+ return null;
+ }
+ } else {
+ i = 0;
}
%_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, s, lastIndex]);
// matchIndices is either null or the lastMatchInfo array.
var matchIndices = %_RegExpExec(this, s, i, lastMatchInfo);
- if (matchIndices == null) {
- if (this.global) {
+ if (matchIndices === null) {
+ if (global) {
+ // Cache negative result only if initial lastIndex was zero.
this.lastIndex = 0;
- if (lastIndex != 0) return matchIndices;
- }
- cache.lastIndex = lastIndex;
+ if (lastIndex !== 0) return matchIndices;
+ }
cache.regExp = this;
- cache.subject = s;
- cache.answer = matchIndices; // Null.
+ cache.subject = s; // Always a string.
+ cache.answer = null;
cache.answerSaved = true; // Safe since no cloning is needed.
cache.type = 'exec';
return matchIndices; // No match.
}
+
+ // Successful match.
lastMatchInfoOverride = null;
var result = BuildResultFromMatchInfo(matchIndices, s);
- if (this.global) {
+ if (global) {
+ // Don't cache positive results for global regexps.
this.lastIndex = lastMatchInfo[CAPTURE1];
} else {
cache.regExp = this;
cache.subject = s;
- cache.lastIndex = lastIndex;
if (saveAnswer) cache.answer = %_RegExpCloneResult(result);
cache.answerSaved = saveAnswer;
cache.type = 'exec';
@@ -273,32 +288,49 @@
}
string = regExpInput;
}
- var s;
- if (IS_STRING(string)) {
- s = string;
- } else {
- s = ToString(string);
- }
var lastIndex = this.lastIndex;
+
var cache = regExpCache;
if (%_ObjectEquals(cache.type, 'test') &&
%_IsRegExpEquivalent(cache.regExp, this) &&
%_ObjectEquals(cache.subject, string) &&
- %_ObjectEquals(cache.lastIndex, lastIndex)) {
- // If this regexp is not global, cache.lastIndex is zero, so we only
get
- // here if this.lastIndex is zero, and resulting this.lastIndex
- // must be zero too, so no change is necessary.
- if (this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
+ %_ObjectEquals(0, lastIndex)) {
+ // The regexp.lastIndex value must be 0 for non-global RegExps, and for
+ // global RegExps we only cache negative results, which gives a
resulting
+ // lastIndex of zero as well.
+ if (global) this.lastIndex = 0;
return cache.answer;
}
+
+ var s;
+ if (IS_STRING(string)) {
+ s = string;
+ } else {
+ s = ToString(string);
+ }
+ var length = s.length;
+
+ // Conversion is required by the ES5 specification (RegExp.prototype.exec
+ // algorithm, step 5) even if the value is discarded for non-global
RegExps.
+ var i = TO_INTEGER(lastIndex);
+ if (global) {
+ if (i < 0 || i > length) {
+ this.lastIndex = 0;
+ return false;
+ }
+ } else {
+ i = 0;
+ }
+
+ var global = this.global;
// Remove irrelevant preceeding '.*' in a test regexp. The expression
// checks whether this.source starts with '.*' and that the third
// char is not a '?'
- if (%_StringCharCodeAt(this.source,0) == 46 && // '.'
- %_StringCharCodeAt(this.source,1) == 42 && // '*'
- %_StringCharCodeAt(this.source,2) != 63) { // '?'
+ if (%_StringCharCodeAt(this.source, 0) == 46 && // '.'
+ %_StringCharCodeAt(this.source, 1) == 42 && // '*'
+ %_StringCharCodeAt(this.source, 2) != 63) { // '?'
if (!%_ObjectEquals(regexp_key, this)) {
regexp_key = this;
regexp_val = new $RegExp(this.source.substring(2,
this.source.length),
@@ -308,34 +340,29 @@
}
if (!regexp_val.test(s)) return false;
}
-
- var length = s.length;
- var i = this.global ? TO_INTEGER(lastIndex) : 0;
-
- cache.type = 'test';
- cache.regExp = this;
- cache.subject = s;
- cache.lastIndex = i;
-
- if (i < 0 || i > length) {
- this.lastIndex = 0;
- cache.answer = false;
- return false;
- }
%_Log('regexp', 'regexp-exec,%0r,%1S,%2i', [this, s, lastIndex]);
// matchIndices is either null or the lastMatchInfo array.
var matchIndices = %_RegExpExec(this, s, i, lastMatchInfo);
- if (matchIndices == null) {
- if (this.global) this.lastIndex = 0;
- cache.answer = false;
- return false;
- }
- lastMatchInfoOverride = null;
- if (this.global) this.lastIndex = lastMatchInfo[CAPTURE1];
- cache.answer = true;
- return true;
+ var result = (matchIndices !== null);
+ if (result) {
+ lastMatchInfoOverride = null;
+ }
+ if (global) {
+ if (result) {
+ this.lastIndex = lastMatchInfo[CAPTURE1];
+ return true;
+ } else {
+ this.lastIndex = 0;
+ if (lastIndex !== 0) return false;
+ }
+ }
+ cache.type = 'test';
+ cache.regExp = this;
+ cache.subject = s;
+ cache.answer = result;
+ return result;
}
@@ -345,12 +372,9 @@
// ecma_2/RegExp/properties-001.js.
var src = this.source ? this.source : '(?:)';
var result = '/' + src + '/';
- if (this.global)
- result += 'g';
- if (this.ignoreCase)
- result += 'i';
- if (this.multiline)
- result += 'm';
+ if (this.global) result += 'g';
+ if (this.ignoreCase) result += 'i';
+ if (this.multiline) result += 'm';
return result;
}
=======================================
--- /branches/bleeding_edge/src/string.js Fri Aug 6 06:04:27 2010
+++ /branches/bleeding_edge/src/string.js Thu Oct 14 05:54:00 2010
@@ -611,7 +611,7 @@
if (%_ObjectEquals(cache.type, 'split') &&
%_IsRegExpEquivalent(cache.regExp, separator) &&
%_ObjectEquals(cache.subject, subject) &&
- %_ObjectEquals(cache.lastIndex, limit)) {
+ %_ObjectEquals(cache.splitLimit, limit)) {
if (cache.answerSaved) {
return CloneDenseArray(cache.answer);
} else {
@@ -622,8 +622,7 @@
cache.type = 'split';
cache.regExp = separator;
cache.subject = subject;
- // Reuse lastIndex field for split limit when type is "split".
- cache.lastIndex = limit;
+ cache.splitLimit = limit;
%_Log('regexp', 'regexp-split,%0S,%1r', [subject, separator]);
=======================================
--- /branches/bleeding_edge/test/mjsunit/regexp.js Fri Aug 20 02:37:22 2010
+++ /branches/bleeding_edge/test/mjsunit/regexp.js Thu Oct 14 05:54:00 2010
@@ -502,3 +502,90 @@
res[3] = "Glopglyf";
assertEquals("Arglebargle", res.foobar);
}
+
+// Test that we perform the spec required conversions in the correct order.
+var log;
+var string = "the string";
+var fakeLastIndex = {
+ valueOf: function() {
+ log.push("li");
+ return 0;
+ }
+ };
+var fakeString = {
+ toString: function() {
+ log.push("ts");
+ return string;
+ },
+ length: 0
+ };
+
+var re = /str/;
+log = [];
+re.lastIndex = fakeLastIndex;
+var result = re.exec(fakeString);
+assertEquals(["str"], result);
+assertEquals(["ts", "li"], log);
+
+// Again, to check if caching interferes.
+log = [];
+re.lastIndex = fakeLastIndex;
+result = re.exec(fakeString);
+assertEquals(["str"], result);
+assertEquals(["ts", "li"], log);
+
+// And one more time, just to be certain.
+log = [];
+re.lastIndex = fakeLastIndex;
+result = re.exec(fakeString);
+assertEquals(["str"], result);
+assertEquals(["ts", "li"], log);
+
+// Now with a global regexp, where lastIndex is actually used.
+re = /str/g;
+log = [];
+re.lastIndex = fakeLastIndex;
+var result = re.exec(fakeString);
+assertEquals(["str"], result);
+assertEquals(["ts", "li"], log);
+
+// Again, to check if caching interferes.
+log = [];
+re.lastIndex = fakeLastIndex;
+result = re.exec(fakeString);
+assertEquals(["str"], result);
+assertEquals(["ts", "li"], log);
+
+// And one more time, just to be certain.
+log = [];
+re.lastIndex = fakeLastIndex;
+result = re.exec(fakeString);
+assertEquals(["str"], result);
+assertEquals(["ts", "li"], log);
+
+
+// Check that properties of RegExp have the correct permissions.
+var re = /x/g;
+var desc = Object.getOwnPropertyDescriptor(re, "global");
+assertEquals(true, desc.value);
+assertEquals(false, desc.configurable);
+assertEquals(false, desc.enumerable);
+assertEquals(false, desc.writable);
+
+desc = Object.getOwnPropertyDescriptor(re, "multiline");
+assertEquals(false, desc.value);
+assertEquals(false, desc.configurable);
+assertEquals(false, desc.enumerable);
+assertEquals(false, desc.writable);
+
+desc = Object.getOwnPropertyDescriptor(re, "ignoreCase");
+assertEquals(false, desc.value);
+assertEquals(false, desc.configurable);
+assertEquals(false, desc.enumerable);
+assertEquals(false, desc.writable);
+
+desc = Object.getOwnPropertyDescriptor(re, "lastIndex");
+assertEquals(0, desc.value);
+assertEquals(false, desc.configurable);
+assertEquals(false, desc.enumerable);
+assertEquals(true, desc.writable);
--
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