Add Syntax Highlighting (this will take a few seconds, probably freezing your browser while it works)
// ==UserScript==
// @name Helgon.net archive and diff
// @namespace http://code.google.com/p/ecmanaut/
// @description Persists all read diary posts at helgon.net in Google Gears (required) and shows diffs when you read an updated version.
// @include http://www.helgon.net/diary/read.asp*
// @include http://www.helgon.net/Diary/read.asp*
// @include http://www.helgon.net/Diary/Read.asp*
// @include http://www.helgon.net/diary/Read.asp*
// ==/UserScript==
var xpath = {
diary: {
title: '//td[@class="subline" and not(a)]',
date: 'following::td[starts-with(.,"Daterat:")]', // relative to title
post: 'following::tr[@class="text1"]/td' // relative to date
}
};
try {
var google = { gears: { factory: new unsafeWindow.GearsFactory } };
var db = google.gears.factory.create("beta.database", "1.0");
} catch(e) {
console.error("Requires Google Gears! Error: "+ e);
return;
}
function $X(xpath, root) {
var got = $x(xpath, root);
return got instanceof Array ? got[0] : got;
}
// list nodes matching this expression, optionally relative to the node `root'
function $x(xpath, root, type) {
var doc = document, result = [], got, next;
if (root)
doc = root.evaluate ? root : root.ownerDocument;
got = doc.evaluate( xpath, root||doc, null, type, null );
switch (got.resultType) {
case got.STRING_TYPE:
return got.stringValue;
case got.NUMBER_TYPE:
return got.numberValue;
case got.BOOLEAN_TYPE:
return got.booleanValue;
default:
while( next = got.iterateNext() )
result.push( next );
return result;
}
}
/**
* Diff by Neil Fraser (LGPL), Copyright 2006 Google Inc.
* http://code.google.com/p/google-diff-match-patch/
*/
var Diff = (function() {
function Diff() {
// Number of seconds to map a diff before giving up. (0 for infinity)
this.Diff_Timeout = 1.0;
// Cost of an empty edit operation in terms of edit characters.
this.Diff_EditCost = 4;
// The size beyond which the double-ended diff activates.
// Double-ending is twice as fast, but less accurate.
this.Diff_DualThreshold = 32;
}
// DIFF FUNCTIONS
/**
* The data structure representing a diff is an array of tuples:
* [[DIFF_DELETE, 'Hello'], [DIFF_INSERT, 'Goodbye'], [DIFF_EQUAL, ' world.']]
* which means: delete 'Hello', add 'Goodbye' and keep ' world.'
*/
var DIFF_DELETE = -1;
var DIFF_INSERT = 1;
var DIFF_EQUAL = 0;
/**
* Find the differences between two texts. Simplifies the problem by stripping
* any common prefix or suffix off the texts before diffing.
* @param {String} text1 Old string to be diffed
* @param {String} text2 New string to be diffed
* @param {Boolean} opt_checklines Optional speedup flag. If present and false,
* then don't run a line-level diff first to identify the changed areas.
* Defaults to true, which does a faster, slightly less optimal diff
* @return {Array} Array of diff tuples
*/
Diff.prototype.diff_main = function(text1, text2, opt_checklines) {
// Check for equality (speedup)
if (text1 == text2) {
return [[DIFF_EQUAL, text1]];
}
if (typeof opt_checklines == 'undefined') {
opt_checklines = true;
}
var checklines = opt_checklines;
// Trim off common prefix (speedup)
var commonlength = this.diff_commonPrefix(text1, text2);
var commonprefix = text1.substring(0, commonlength);
text1 = text1.substring(commonlength);
text2 = text2.substring(commonlength);
// Trim off common suffix (speedup)
commonlength = this.diff_commonSuffix(text1, text2);
var commonsuffix = text1.substring(text1.length - commonlength);
text1 = text1.substring(0, text1.length - commonlength);
text2 = text2.substring(0, text2.length - commonlength);
// Compute the diff on the middle block
var diffs = this.diff_compute(text1, text2, checklines);
// Restore the prefix and suffix
if (commonprefix) {
diffs.unshift([DIFF_EQUAL, commonprefix]);
}
if (commonsuffix) {
diffs.push([DIFF_EQUAL, commonsuffix]);
}
this.diff_cleanupMerge(diffs);
return diffs;
};
/**
* Find the differences between two texts.
* @param {String} text1 Old string to be diffed
* @param {String} text2 New string to be diffed
* @param {Boolean} checklines Speedup flag. If false, then don't run a
* line-level diff first to identify the changed areas.
* If true, then run a faster, slightly less optimal diff
* @return {Array} Array of diff tuples
*/
Diff.prototype.diff_compute = function(text1, text2, checklines) {
var diffs;
if (!text1) {
// Just add some text (speedup)
return [[DIFF_INSERT, text2]];
}
if (!text2) {
// Just delete some text (speedup)
return [[DIFF_DELETE, text1]];
}
var longtext = text1.length > text2.length ? text1 : text2;
var shorttext = text1.length > text2.length ? text2 : text1;
var i = longtext.indexOf(shorttext);
if (i != -1) {
// Shorter text is inside the longer text (speedup)
diffs = [[DIFF_INSERT, longtext.substring(0, i)],
[DIFF_EQUAL, shorttext],
[DIFF_INSERT, longtext.substring(i + shorttext.length)]];
// Swap insertions for deletions if diff is reversed.
if (text1.length > text2.length) {
diffs[0][0] = diffs[2][0] = DIFF_DELETE;
}
return diffs;
}
longtext = shorttext = null; // Garbage collect
// Check to see if the problem can be split in two.
var hm = this.diff_halfMatch(text1, text2);
if (hm) {
// A half-match was found, sort out the return data.
var text1_a = hm[0];
var text1_b = hm[1];
var text2_a = hm[2];
var text2_b = hm[3];
var mid_common = hm[4];
// Send both pairs off for separate processing.
var diffs_a = this.diff_main(text1_a, text2_a, checklines);
var diffs_b = this.diff_main(text1_b, text2_b, checklines);
// Merge the results.
return diffs_a.concat([[DIFF_EQUAL, mid_common]], diffs_b);
}
// Perform a real diff.
if (checklines && text1.length + text2.length < 250) {
// Too trivial for the overhead.
checklines = false;
}
var linearray;
if (checklines) {
// Scan the text on a line-by-line basis first.
var a = this.diff_linesToChars(text1, text2);
text1 = a[0];
text2 = a[1];
linearray = a[2];
}
diffs = this.diff_map(text1, text2);
if (!diffs) {
// No acceptable result.
diffs = [[DIFF_DELETE, text1], [DIFF_INSERT, text2]];
}
if (checklines) {
// Convert the diff back to original text.
this.diff_charsToLines(diffs, linearray);
// Eliminate freak matches (e.g. blank lines)
this.diff_cleanupSemantic(diffs);
// Rediff any replacement blocks, this time character-by-character.
// Add a dummy entry at the end.
diffs.push([DIFF_EQUAL, '']);
var pointer = 0;
var count_delete = 0;
var count_insert = 0;
var text_delete = '';
var text_insert = '';
while (pointer < diffs.length) {
switch (diffs[pointer][0]) {
case DIFF_INSERT:
count_insert++;
text_insert += diffs[pointer][1];
break;
case DIFF_DELETE:
count_delete++;
text_delete += diffs[pointer][1];
break;
case DIFF_EQUAL:
// Upon reaching an equality, check for prior redundancies.
if (count_delete >= 1 && count_insert >= 1) {
// Delete the offending records and add the merged ones.
var a = this.diff_main(text_delete, text_insert, false);
diffs.splice(pointer - count_delete - count_insert,
count_delete + count_insert);
pointer = pointer - count_delete - count_insert;
for (var j = a.length - 1; j >= 0; j--) {
diffs.splice(pointer, 0, a[j]);
}
pointer = pointer + a.length;
}
count_insert = 0;
count_delete = 0;
text_delete = '';
text_insert = '';
break;
}
pointer++;
}
diffs.pop(); // Remove the dummy entry at the end.
}
return diffs;
};
/**
* Split two texts into an array of strings. Reduce the texts to a string of
* hashes where each Unicode character represents one line.
* @param {String} text1 First string
* @param {String} text2 Second string
* @return {Array} Three element Array, containing the encoded text1,
* the encoded text2 and the array of unique strings. The zeroth element
* of the array of unique strings is intentionally blank.
*/
Diff.prototype.diff_linesToChars = function(text1, text2) {
var lineArray = []; // e.g. lineArray[4] == 'Hello\n'
var lineHash = {}; // e.g. lineHash['Hello\n'] == 4
// '\x00' is a valid character, but various debuggers don't like it.
// So we'll insert a junk entry to avoid generating a null character.
lineArray[0] = '';
/**
* Split a text into an array of strings. Reduce the texts to a string of
* hashes where each Unicode character represents one line.
* Modifies linearray and linehash through being a closure.
* @param {String} text String to encode
* @return {String} Encoded string
*/
function diff_linesToCharsMunge(text) {
var chars = '';
// Walk the text, pulling out a substring for each line.
// text.split('\n') would would temporarily double our memory footprint.
// Modifying text would create many large strings to garbage collect.
var lineStart = 0;
var lineEnd = 0;
// Keeping our own length variable is faster then looking it up.
var lineArrayLength = lineArray.length;
while (lineEnd < text.length - 1) {
lineEnd = text.indexOf('\n', lineStart);
if (lineEnd == -1) {
lineEnd = text.length - 1;
}
var line = text.substring(lineStart, lineEnd + 1);
lineStart = lineEnd + 1;
if (lineHash.hasOwnProperty ? lineHash.hasOwnProperty(line) :
(lineHash[line] !== undefined)) {
chars += String.fromCharCode(lineHash[line]);
} else {
chars += String.fromCharCode(lineArrayLength);
lineHash[line] = lineArrayLength;
lineArray[lineArrayLength++] = line;
}
}
return chars;
}
var chars1 = diff_linesToCharsMunge(text1);
var chars2 = diff_linesToCharsMunge(text2);
return [chars1, chars2, lineArray];
};
/**
* Rehydrate the text in a diff from a string of line hashes to real lines of
* text.
* @param {Array} diffs Array of diff tuples
* @param {Array} lineArray Array of unique strings
*/
Diff.prototype.diff_charsToLines = function(diffs, lineArray) {
for (var x = 0; x < diffs.length; x++) {
var chars = diffs[x][1];
var text = [];
for (var y = 0; y < chars.length; y++) {
text[y] = lineArray[chars.charCodeAt(y)];
}
diffs[x][1] = text.join('');
}
};
/**
* Explore the intersection points between the two texts.
* @param {String} text1 Old string to be diffed
* @param {String} text2 New string to be diffed
* @return {Array | Null} Array of diff tuples or null if no diff available
*/
Diff.prototype.diff_map = function(text1, text2) {
// Don't run for too long.
var ms_end = (new Date()).getTime() + this.Diff_Timeout * 1000;
var max_d = text1.length + text2.length - 1;
var doubleEnd = this.Diff_DualThreshold * 2 < max_d;
var v_map1 = [];
var v_map2 = [];
var v1 = {};
var v2 = {};
v1[1] = 0;
v2[1] = 0;
var x, y;
var footstep; // Used to track overlapping paths.
var footsteps = {};
var done = false;
// Safari 1.x doesn't have hasOwnProperty
var hasOwnProperty = !!(footsteps.hasOwnProperty);
// If the total number of characters is odd, then the front path will collide
// with the reverse path.
var front = (text1.length + text2.length) % 2;
for (var d = 0; d < max_d; d++) {
// Bail out if timeout reached.
if (this.Diff_Timeout > 0 && (new Date()).getTime() > ms_end) {
return null;
}
// Walk the front path one step.
v_map1[d] = {};
for (var k = -d; k <= d; k += 2) {
if (k == -d || k != d && v1[k - 1] < v1[k + 1]) {
x = v1[k + 1];
} else {
x = v1[k - 1] + 1;
}
y = x - k;
if (doubleEnd) {
footstep = x + ',' + y;
if (front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) :
(footsteps[footstep] !== undefined))) {
done = true;
}
if (!front) {
footsteps[footstep] = d;
}
}
while (!done && x < text1.length && y < text2.length &&
text1.charAt(x) == text2.charAt(y)) {
x++;
y++;
if (doubleEnd) {
footstep = x + ',' + y;
if (front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) :
(footsteps[footstep] !== undefined))) {
done = true;
}
if (!front) {
footsteps[footstep] = d;
}
}
}
v1[k] = x;
v_map1[d][x + ',' + y] = true;
if (x == text1.length && y == text2.length) {
// Reached the end in single-path mode.
return this.diff_path1(v_map1, text1, text2);
} else if (done) {
// Front path ran over reverse path.
v_map2 = v_map2.slice(0, footsteps[footstep] + 1);
var a = this.diff_path1(v_map1, text1.substring(0, x),
text2.substring(0, y));
return a.concat(this.diff_path2(v_map2, text1.substring(x),
text2.substring(y)));
}
}
if (doubleEnd) {
// Walk the reverse path one step.
v_map2[d] = {};
for (var k = -d; k <= d; k += 2) {
if (k == -d || k != d && v2[k - 1] < v2[k + 1]) {
x = v2[k + 1];
} else {
x = v2[k - 1] + 1;
}
y = x - k;
footstep = (text1.length - x) + ',' + (text2.length - y);
if (!front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) :
(footsteps[footstep] !== undefined))) {
done = true;
}
if (front) {
footsteps[footstep] = d;
}
while (!done && x < text1.length && y < text2.length &&
text1.charAt(text1.length - x - 1) ==
text2.charAt(text2.length - y - 1)) {
x++;
y++;
footstep = (text1.length - x) + ',' + (text2.length - y);
if (!front && (hasOwnProperty ? footsteps.hasOwnProperty(footstep) :
(footsteps[footstep] !== undefined))) {
done = true;
}
if (front) {
footsteps[footstep] = d;
}
}
v2[k] = x;
v_map2[d][x + ',' + y] = true;
if (done) {
// Reverse path ran over front path.
v_map1 = v_map1.slice(0, footsteps[footstep] + 1);
var a = this.diff_path1(v_map1, text1.substring(0, text1.length - x),
text2.substring(0, text2.length - y));
return a.concat(this.diff_path2(v_map2,
text1.substring(text1.length - x),
text2.substring(text2.length - y)));
}
}
}
}
// Number of diffs equals number of characters, no commonality at all.
return null;
};
/**
* Work from the middle back to the start to determine the path.
* @param {Array} v_map Array of paths.
* @param {String} text1 Old string fragment to be diffed
* @param {String} text2 New string fragment to be diffed
* @return {Array} Array of diff tuples
*/
Diff.prototype.diff_path1 = function(v_map, text1, text2) {
var path = [];
var x = text1.length;
var y = text2.length;
var last_op = null;
for (var d = v_map.length - 2; d >= 0; d--) {
while (1) {
if (v_map[d].hasOwnProperty ? v_map[d].hasOwnProperty((x - 1) + ',' + y) :
(v_map[d][(x - 1) + ',' + y] !== undefined)) {
x--;
if (last_op === DIFF_DELETE) {
path[0][1] = text1.charAt(x) + path[0][1];
} else {
path.unshift([DIFF_DELETE, text1.charAt(x)]);
}
last_op = DIFF_DELETE;
break;
} else if (v_map[d].hasOwnProperty ?
v_map[d].hasOwnProperty(x + ',' + (y - 1)) :
(v_map[d][x + ',' + (y - 1)] !== undefined)) {
y--;
if (last_op === DIFF_INSERT) {
path[0][1] = text2.charAt(y) + path[0][1];
} else {
path.unshift([DIFF_INSERT, text2.charAt(y)]);
}
last_op = DIFF_INSERT;
break;
} else {
x--;
y--;
//if (text1.charAt(x) != text2.charAt(y)) {
// throw new Error('No diagonal. Can\'t happen. (diff_path1)');
//}
if (last_op === DIFF_EQUAL) {
path[0][1] = text1.charAt(x) + path[0][1];
} else {
path.unshift([DIFF_EQUAL, text1.charAt(x)]);
}
last_op = DIFF_EQUAL;
}
}
}
return path;
};
/**
* Work from the middle back to the end to determine the path.
* @param {Array} v_map Array of paths.
* @param {String} text1 Old string fragment to be diffed
* @param {String} text2 New string fragment to be diffed
* @return {Array} Array of diff tuples
*/
Diff.prototype.diff_path2 = function(v_map, text1, text2) {
var path = [];
var pathLength = 0;
var x = text1.length;
var y = text2.length;
var last_op = null;
for (var d = v_map.length - 2; d >= 0; d--) {
while (1) {
if (v_map[d].hasOwnProperty ? v_map[d].hasOwnProperty((x - 1) + ',' + y) :
(v_map[d][(x - 1) + ',' + y] !== undefined)) {
x--;
if (last_op === DIFF_DELETE) {
path[pathLength - 1][1] += text1.charAt(text1.length - x - 1);
} else {
path[pathLength++] = [DIFF_DELETE, text1.charAt(text1.length - x - 1)];
}
last_op = DIFF_DELETE;
break;
} else if (v_map[d].hasOwnProperty ?
v_map[d].hasOwnProperty(x + ',' + (y - 1)) :
(v_map[d][x + ',' + (y - 1)] !== undefined)) {
y--;
if (last_op === DIFF_INSERT) {
path[pathLength - 1][1] += text2.charAt(text2.length - y - 1);
} else {
path[pathLength++] = [DIFF_INSERT, text2.charAt(text2.length - y - 1)];
}
last_op = DIFF_INSERT;
break;
} else {
x--;
y--;
//if (text1.charAt(text1.length - x - 1) !=
// text2.charAt(text2.length - y - 1)) {
// throw new Error('No diagonal. Can\'t happen. (diff_path2)');
//}
if (last_op === DIFF_EQUAL) {
path[pathLength - 1][1] += text1.charAt(text1.length - x - 1);
} else {
path[pathLength++] = [DIFF_EQUAL, text1.charAt(text1.length - x - 1)];
}
last_op = DIFF_EQUAL;
}
}
}
return path;
};
/**
* Determine the common prefix of two strings
* @param {String} text1 First string
* @param {String} text2 Second string
* @return {Number} The number of characters common to the start of each
* string.
*/
Diff.prototype.diff_commonPrefix = function(text1, text2) {
// Quick check for common null cases.
if (!text1 || !text2 || text1.charCodeAt(0) !== text2.charCodeAt(0)) {
return 0;
}
// Binary search.
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
var pointermin = 0;
var pointermax = Math.min(text1.length, text2.length);
var pointermid = pointermax;
var pointerstart = 0;
while (pointermin < pointermid) {
if (text1.substring(pointerstart, pointermid) ==
text2.substring(pointerstart, pointermid)) {
pointermin = pointermid;
pointerstart = pointermin;
} else {
pointermax = pointermid;
}
pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
}
return pointermid;
};
/**
* Determine the common suffix of two strings
* @param {String} text1 First string
* @param {String} text2 Second string
* @return {Number} The number of characters common to the end of each string.
*/
Diff.prototype.diff_commonSuffix = function(text1, text2) {
// Quick check for common null cases.
if (!text1 || !text2 || text1.charCodeAt(text1.length - 1) !==
text2.charCodeAt(text2.length - 1)) {
return 0;
}
// Binary search.
// Performance analysis: http://neil.fraser.name/news/2007/10/09/
var pointermin = 0;
var pointermax = Math.min(text1.length, text2.length);
var pointermid = pointermax;
var pointerend = 0;
while (pointermin < pointermid) {
if (text1.substring(text1.length - pointermid, text1.length - pointerend) ==
text2.substring(text2.length - pointermid, text2.length - pointerend)) {
pointermin = pointermid;
pointerend = pointermin;
} else {
pointermax = pointermid;
}
pointermid = Math.floor((pointermax - pointermin) / 2 + pointermin);
}
return pointermid;
};
/**
* Do the two texts share a substring which is at least half the length of the
* longer text?
* @param {String} text1 First string
* @param {String} text2 Second string
* @return {Array} Five element Array, containing the prefix of text1, the
* suffix of text1, the prefix of text2, the suffix of text2 and the
* common middle. Or null if there was no match.
*/
Diff.prototype.diff_halfMatch = function(text1, text2) {
var longtext = text1.length > text2.length ? text1 : text2;
var shorttext = text1.length > text2.length ? text2 : text1;
if (longtext.length < 10 || shorttext.length < 1) {
return null; // Pointless.
}
var dmp = this; // 'this' becomes 'window' in a closure.
/**
* Does a substring of shorttext exist within longtext such that the substring
* is at least half the length of longtext?
* Closure, but does not reference any external variables.
* @param {String} longtext Longer string
* @param {String} shorttext Shorter string
* @param {Number} i Start index of quarter length substring within longtext
* @return {Array|Null} Five element Array, containing the prefix of longtext,
* the suffix of longtext, the prefix of shorttext, the suffix of
* shorttext and the common middle. Or null if there was no match.
*/
function diff_halfMatchI(longtext, shorttext, i) {
// Start with a 1/4 length substring at position i as a seed.
var seed = longtext.substring(i, i + Math.floor(longtext.length / 4));
var j = -1;
var best_common = '';
var best_longtext_a, best_longtext_b, best_shorttext_a, best_shorttext_b;
while ((j = shorttext.indexOf(seed, j + 1)) != -1) {
var prefixLength = dmp.diff_commonPrefix(longtext.substring(i),
shorttext.substring(j));
var suffixLength = dmp.diff_commonSuffix(longtext.substring(0, i),
shorttext.substring(0, j));
if (best_common.length < suffixLength + prefixLength) {
best_common = shorttext.substring(j - suffixLength, j) +
shorttext.substring(j, j + prefixLength);
best_longtext_a = longtext.substring(0, i - suffixLength);
best_longtext_b = longtext.substring(i + prefixLength);
best_shorttext_a = shorttext.substring(0, j - suffixLength);
best_shorttext_b = shorttext.substring(j + prefixLength);
}
}
if (best_common.length >= longtext.length / 2) {
return [best_longtext_a, best_longtext_b,
best_shorttext_a, best_shorttext_b, best_common];
} else {
return null;
}
}
// First check if the second quarter is the seed for a half-match.
var hm1 = diff_halfMatchI(longtext, shorttext,
Math.ceil(longtext.length / 4));
// Check again based on the third quarter.
var hm2 = diff_halfMatchI(longtext, shorttext,
Math.ceil(longtext.length / 2));
var hm;
if (!hm1 && !hm2) {
return null;
} else if (!hm2) {
hm = hm1;
} else if (!hm1) {
hm = hm2;
} else {
// Both matched. Select the longest.
hm = hm1[4].length > hm2[4].length ? hm1 : hm2;
}
// A half-match was found, sort out the return data.
var text1_a, text1_b, text2_a, text2_b;
if (text1.length > text2.length) {
text1_a = hm[0];
text1_b = hm[1];
text2_a = hm[2];
text2_b = hm[3];
} else {
text2_a = hm[0];
text2_b = hm[1];
text1_a = hm[2];
text1_b = hm[3];
}
var mid_common = hm[4];
return [text1_a, text1_b, text2_a, text2_b, mid_common];
};
/**
* Reduce the number of edits by eliminating semantically trivial equalities.
* @param {Array} diffs Array of diff tuples
*/
Diff.prototype.diff_cleanupSemantic = function(diffs) {
var changes = false;
var equalities = []; // Stack of indices where equalities are found.
var equalitiesLength = 0; // Keeping our own length var is faster in JS.
var lastequality = null; // Always equal to equalities[equalitiesLength-1][1]
var pointer = 0; // Index of current position.
// Number of characters that changed prior to the equality.
var length_changes1 = 0;
// Number of characters that changed after the equality.
var length_changes2 = 0;
while (pointer < diffs.length) {
if (diffs[pointer][0] == DIFF_EQUAL) { // equality found
equalities[equalitiesLength++] = pointer;
length_changes1 = length_changes2;
length_changes2 = 0;
lastequality = diffs[pointer][1];
} else { // an insertion or deletion
length_changes2 += diffs[pointer][1].length;
if (lastequality !== null && (lastequality.length <= length_changes1) &&
(lastequality.length <= length_changes2)) {
// Duplicate record
diffs.splice(equalities[equalitiesLength - 1], 0,
[DIFF_DELETE, lastequality]);
// Change second copy to insert.
diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
// Throw away the equality we just deleted.
equalitiesLength--;
// Throw away the previous equality (it needs to be reevaluated).
equalitiesLength--;
pointer = equalitiesLength ? equalities[equalitiesLength - 1] : -1;
length_changes1 = 0; // Reset the counters.
length_changes2 = 0;
lastequality = null;
changes = true;
}
}
pointer++;
}
if (changes) {
this.diff_cleanupMerge(diffs);
}
this.diff_cleanupSemanticLossless(diffs);
};
/**
* Look for single edits surrounded on both sides by equalities
* which can be shifted sideways to align the edit to a word boundary.
* e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
* @param {Array} diffs Array of diff tuples
*/
Diff.prototype.diff_cleanupSemanticLossless = function(diffs) {
/**
* Given three strings, compute a score representing whether the two internal
* boundaries fall on word boundaries.
* Closure, but does not reference any external variables.
* @param {String} one First string
* @param {String} two Second string
* @param {String} three Third string
* @return {Number} The score.
*/
function diff_cleanupSemanticScore(one, two, three) {
var whitespace = /\s/;
var score = 0;
if (one.charAt(one.length - 1).match(whitespace) ||
two.charAt(0).match(whitespace)) {
score++;
}
if (two.charAt(two.length - 1).match(whitespace) ||
three.charAt(0).match(whitespace)) {
score++;
}
return score;
}
var pointer = 1;
// Intentionally ignore the first and last element (don't need checking).
while (pointer < diffs.length - 1) {
if (diffs[pointer - 1][0] == DIFF_EQUAL &&
diffs[pointer + 1][0] == DIFF_EQUAL) {
// This is a single edit surrounded by equalities.
var equality1 = diffs[pointer - 1][1];
var edit = diffs[pointer][1];
var equality2 = diffs[pointer + 1][1];
// First, shift the edit as far left as possible.
var commonOffset = this.diff_commonSuffix(equality1, edit);
if (commonOffset) {
var commonString = edit.substring(edit.length - commonOffset);
equality1 = equality1.substring(0, equality1.length - commonOffset);
edit = commonString + edit.substring(0, edit.length - commonOffset);
equality2 = commonString + equality2;
}
// Second, step character by character right, looking for the best fit.
var bestEquality1 = equality1;
var bestEdit = edit;
var bestEquality2 = equality2;
var bestScore = diff_cleanupSemanticScore(equality1, edit, equality2);
while (edit.charAt(0) === equality2.charAt(0)) {
equality1 += edit.charAt(0);
edit = edit.substring(1) + equality2.charAt(0);
equality2 = equality2.substring(1);
var score = diff_cleanupSemanticScore(equality1, edit, equality2);
if (score >= bestScore) {
bestScore = score;
bestEquality1 = equality1;
bestEdit = edit;
bestEquality2 = equality2;
}
}
if (diffs[pointer - 1][1] != bestEquality1) {
// We have an improvement, save it back to the diff.
diffs[pointer - 1][1] = bestEquality1;
diffs[pointer][1] = bestEdit;
diffs[pointer + 1][1] = bestEquality2;
}
}
pointer++;
}
};
/**
* Reduce the number of edits by eliminating operationally trivial equalities.
* @param {Array} diffs Array of diff tuples
*/
Diff.prototype.diff_cleanupEfficiency = function(diffs) {
var changes = false;
var equalities = []; // Stack of indices where equalities are found.
var equalitiesLength = 0; // Keeping our own length var is faster in JS.
var lastequality = ''; // Always equal to equalities[equalitiesLength-1][1]
var pointer = 0; // Index of current position.
// Is there an insertion operation before the last equality.
var pre_ins = false;
// Is there a deletion operation before the last equality.
var pre_del = false;
// Is there an insertion operation after the last equality.
var post_ins = false;
// Is there a deletion operation after the last equality.
var post_del = false;
while (pointer < diffs.length) {
if (diffs[pointer][0] == DIFF_EQUAL) { // equality found
if (diffs[pointer][1].length < this.Diff_EditCost &&
(post_ins || post_del)) {
// Candidate found.
equalities[equalitiesLength++] = pointer;
pre_ins = post_ins;
pre_del = post_del;
lastequality = diffs[pointer][1];
} else {
// Not a candidate, and can never become one.
equalitiesLength = 0;
lastequality = '';
}
post_ins = post_del = false;
} else { // an insertion or deletion
if (diffs[pointer][0] == DIFF_DELETE) {
post_del = true;
} else {
post_ins = true;
}
/*
* Five types to be split:
* <ins>A</ins><del>B</del>XY<ins>C</ins><del>D</del>
* <ins>A</ins>X<ins>C</ins><del>D</del>
* <ins>A</ins><del>B</del>X<ins>C</ins>
* <ins>A</del>X<ins>C</ins><del>D</del>
* <ins>A</ins><del>B</del>X<del>C</del>
*/
if (lastequality && ((pre_ins && pre_del && post_ins && post_del) ||
((lastequality.length < this.Diff_EditCost / 2) &&
(pre_ins + pre_del + post_ins + post_del) == 3))) {
// Duplicate record
diffs.splice(equalities[equalitiesLength - 1], 0,
[DIFF_DELETE, lastequality]);
// Change second copy to insert.
diffs[equalities[equalitiesLength - 1] + 1][0] = DIFF_INSERT;
equalitiesLength--; // Throw away the equality we just deleted;
lastequality = '';
if (pre_ins && pre_del) {
// No changes made which could affect previous entry, keep going.
post_ins = post_del = true;
equalitiesLength = 0;
} else {
equalitiesLength--; // Throw away the previous equality;
pointer = equalitiesLength ? equalities[equalitiesLength - 1] : -1;
post_ins = post_del = false;
}
changes = true;
}
}
pointer++;
}
if (changes) {
this.diff_cleanupMerge(diffs);
}
};
/**
* Reorder and merge like edit sections. Merge equalities.
* Any edit section can move as long as it doesn't cross an equality.
* @param {Array} diffs Array of diff tuples
*/
Diff.prototype.diff_cleanupMerge = function(diffs) {
diffs.push([DIFF_EQUAL, '']); // Add a dummy entry at the end.
var pointer = 0;
var count_delete = 0;
var count_insert = 0;
var text_delete = '';
var text_insert = '';
var commonlength;
while (pointer < diffs.length) {
switch (diffs[pointer][0]) {
case DIFF_INSERT:
count_insert++;
text_insert += diffs[pointer][1];
pointer++;
break;
case DIFF_DELETE:
count_delete++;
text_delete += diffs[pointer][1];
pointer++;
break;
case DIFF_EQUAL:
// Upon reaching an equality, check for prior redundancies.
if (count_delete !== 0 || count_insert !== 0) {
if (count_delete !== 0 && count_insert !== 0) {
// Factor out any common prefixies.
commonlength = this.diff_commonPrefix(text_insert, text_delete);
if (commonlength !== 0) {
if ((pointer - count_delete - count_insert) > 0 &&
diffs[pointer - count_delete - count_insert - 1][0] ==
DIFF_EQUAL) {
diffs[pointer - count_delete - count_insert - 1][1] +=
text_insert.substring(0, commonlength);
} else {
diffs.splice(0, 0, [DIFF_EQUAL,
text_insert.substring(0, commonlength)]);
pointer++;
}
text_insert = text_insert.substring(commonlength);
text_delete = text_delete.substring(commonlength);
}
// Factor out any common suffixies.
commonlength = this.diff_commonSuffix(text_insert, text_delete);
if (commonlength !== 0) {
diffs[pointer][1] = text_insert.substring(text_insert.length -
commonlength) + diffs[pointer][1];
text_insert = text_insert.substring(0, text_insert.length -
commonlength);
text_delete = text_delete.substring(0, text_delete.length -
commonlength);
}
}
// Delete the offending records and add the merged ones.
if (count_delete === 0) {
diffs.splice(pointer - count_delete - count_insert,
count_delete + count_insert, [DIFF_INSERT, text_insert]);
} else if (count_insert === 0) {
diffs.splice(pointer - count_delete - count_insert,
count_delete + count_insert, [DIFF_DELETE, text_delete]);
} else {
diffs.splice(pointer - count_delete - count_insert,
count_delete + count_insert, [DIFF_DELETE, text_delete],
[DIFF_INSERT, text_insert]);
}
pointer = pointer - count_delete - count_insert +
(count_delete ? 1 : 0) + (count_insert ? 1 : 0) + 1;
} else if (pointer !== 0 && diffs[pointer - 1][0] == DIFF_EQUAL) {
// Merge this equality with the previous one.
diffs[pointer - 1][1] += diffs[pointer][1];
diffs.splice(pointer, 1);
} else {
pointer++;
}
count_insert = 0;
count_delete = 0;
text_delete = '';
text_insert = '';
break;
}
}
if (diffs[diffs.length - 1][1] === '') {
diffs.pop(); // Remove the dummy entry at the end.
}
// Second pass: look for single edits surrounded on both sides by equalities
// which can be shifted sideways to eliminate an equality.
// e.g: A<ins>BA</ins>C -> <ins>AB</ins>AC
var changes = false;
pointer = 1;
// Intentionally ignore the first and last element (don't need checking).
while (pointer < diffs.length - 1) {
if (diffs[pointer - 1][0] == DIFF_EQUAL &&
diffs[pointer + 1][0] == DIFF_EQUAL) {
// This is a single edit surrounded by equalities.
if (diffs[pointer][1].substring(diffs[pointer][1].length -
diffs[pointer - 1][1].length) == diffs[pointer - 1][1]) {
// Shift the edit over the previous equality.
diffs[pointer][1] = diffs[pointer - 1][1] +
diffs[pointer][1].substring(0, diffs[pointer][1].length -
diffs[pointer - 1][1].length);
diffs[pointer + 1][1] = diffs[pointer - 1][1] + diffs[pointer + 1][1];
diffs.splice(pointer - 1, 1);
changes = true;
} else if (diffs[pointer][1].substring(0, diffs[pointer + 1][1].length)
== diffs[pointer + 1][1]) {
// Shift the edit over the next equality.
diffs[pointer - 1][1] += diffs[pointer + 1][1];
diffs[pointer][1] =
diffs[pointer][1].substring(diffs[pointer + 1][1].length) +
diffs[pointer + 1][1];
diffs.splice(pointer + 1, 1);
changes = true;
}
}
pointer++;
}
// If shifts were made, the diff needs reordering and another shift sweep.
if (changes) {
this.diff_cleanupMerge(diffs);
}
};
/**
* Add an index to each tuple, represents where the tuple is located in text2.
* e.g. [[DIFF_DELETE, 'h', 0], [DIFF_INSERT, 'c', 0], [DIFF_EQUAL, 'at', 1]]
* @param {Array} diffs Array of diff tuples
*/
Diff.prototype.diff_addIndex = function(diffs) {
var i = 0;
for (var x = 0; x < diffs.length; x++) {
diffs[x][2] = i;
if (diffs[x][0] !== DIFF_DELETE) {
i += diffs[x][1].length;
}
}
};
/**
* Convert a diff array into a pretty HTML report.
* @param {Array} diffs Array of diff tuples
* @return {String} HTML representation
*/
Diff.prototype.diff_prettyHtml = function(diffs) {
this.diff_addIndex(diffs);
var html = [];
for (var x = 0; x < diffs.length; x++) {
var m = diffs[x][0]; // Mode (delete, equal, insert)
var t = diffs[x][1]; // Text of change.
var i = diffs[x][2]; // Index of change.
t = t.replace(/&/g, '&').replace(/</g, '<').replace(/>/g, '>');
t = t.replace(/\n/g, '¶<BR>');
switch (m) {
case DIFF_INSERT:
html[x] = '<ins style="background:#E6FFE6;">' + t + '</INS>';
break;
case DIFF_DELETE:
html[x] = '<del style="background:#FFE6E6;">' + t + '</del>';
break;
case DIFF_EQUAL:
html[x] = '<span>' + t + '</span>';
break;
}
}
return html.join('');
};
return new Diff;
})();
var Helgon = {
Date: {
// Lördagen den 25:e juni 2005 kl 02:02
// 28/5-06 kl 22:10
// <Idag|Igår|D/M> kl <hh:mm>
parse: function(date, laterdate) {
function set(d, to) {
if (to.Y) {
var y = parseInt(to.Y, 10);
if (y < 100)
y = 2000 + y;
d.setFullYear(y);
}
if (to.M) {
var m = to.M;
if (m.length > 3) {
m = "janfebmaraprmajjunjulaugsepoktnovdec".indexOf(m.slice(1,3))/3;
if (m < 0)
throw prompt("Failed to parse month from:", to.M);
} else
m = parseInt(m, 10) - 1;
d.setMonth(m);
}
if (to.D) d.setDate(parseInt(to.D, 10));
if (to.h) d.setHours(parseInt(to.h, 10));
if (to.m) d.setMinutes(parseInt(to.m, 10));
d.setSeconds(0);
d.setMilliseconds(0);
return d;
}
var text = date.toLowerCase();
var hhmm = /\s*kl\s+(\d+):(\d+)/.exec( text );
if (!hhmm)
throw prompt("Failed to parse time from:", date);
text = RegExp.leftContext; // shave off time part
var today = new Date; today.setHours( 0 );
var yesterday = new Date(today.getTime()-72e5);
var D, M, Y = today.getFullYear();
var jan = new Date(Y, 1, 1);
var dmy4 = /den\s+(\d+)\S*\s+(\S+)\s+(\d+)/.exec( text );
if (dmy4) {
date = set(jan, {Y: dmy4[3], M: dmy4[2], D: dmy4[1] });
} else {
var dmy2 = /(\d+)\/(\d+)-(\d+)/.exec( text );
if (dmy2) {
date = set(jan, {Y: dmy2[3], M: dmy2[2], D: dmy2[1] });
} else {
var dm = /(\d+)\/(\d+)/.exec( text );
if (dm) {
date = set(today, {M: dm[2], D: dm[1] });
while (laterdate && (date > laterdate))
date.setFullYear( date.getFullYear()-1 );
} else {
if (text.match(/idag/))
date = today;
else if (text.match(/ig\345r/))
date = yesterday;
else
throw prompt("Failed to parse date from:", text);
}
}
}
return set(date, {h: hhmm[1], m: hhmm[2]});
}
}
};
function query(sql) {
function row2js( rs ) {
var obj = {};
if (rs.isValidRow()) {
var max = rs.fieldCount();
for (var i = 0; i < max; i++)
obj[rs.fieldName(i)] = rs.field(i);
rs.next();
}
return obj;
};
if (!db) return null;
var args = [].slice.call(arguments, 1);
var read = sql.match( /^select/i );
try {
//console.info("Query: %x %x", sql, args);
db.open("helgon");
if (!read) db.execute("BEGIN").close();
var rs = db.execute( sql, args );
if (!rs.isValidRow()) {
rs.close();
if (!read) db.execute("COMMIT").close();
db && db.close();
return null;
}
var got = rs.fieldCount() == 1 ? rs.field(0) : row2js( rs );
rs.close();
if (!read) db.execute("COMMIT").close();
db.close();
return got;
} catch(e) {
console.warn( e.message );
rs && rs.close && rs.close();
db && db.close();
}
}
function update(table, data) {
var fields = [], q = [], values = [];
for (var name in data) {
fields.push( name );
values.push( data[name] );
q.push("?");
}
values.unshift("INSERT OR REPLACE INTO "+ table +" ("+ fields.join(", ") +")"+
" VALUES ("+ q.join(", ") +")");
return query.apply(this, values);
}
function initDB() {
query("CREATE TABLE IF NOT EXISTS diary (" +
"id INTEGER NOT NULL PRIMARY KEY, " +
"uid INTEGER NOT NULL, " +
"ctime BLOB NOT NULL, " +
"mtime BLOB NOT NULL, " +
"title TEXT NOT NULL, " +
"body TEXT NOT NULL)");
}
function isodate(d) {
function pad(n) { return n < 10 ? "0"+n : n; };
return [d.getFullYear(), pad(d.getMonth()+1), pad(d.getDate())].join("-") +
" " + pad(d.getHours()) + ":" + pad(d.getMinutes());
}
function parsePost() {
var title = $X(xpath.diary.title);
var date = $X(xpath.diary.date, title);
var post = $X(xpath.diary.post, date);
return {
title: title.textContent,
date: isodate(Helgon.Date.parse(date.textContent)),
body: post.innerHTML,
node: post,
uid: location.search.match(/[&?]UserID=(\d+)/i)[1],
id: location.search.match(/[&?]ID=(\d+)/i)[1]
};
}
function readPost(id) {
return query("SELECT * FROM diary WHERE id=?", id);
}
function diffDiaryPost() {
var post = parsePost();
var data = { id: post.id, uid: post.uid, ctime: post.date, mtime: post.date,
title:post.title, body: post.body };
var old = readPost(post.id);
if (old) {
if (old.title != post.title)
$X(xpath.diary.title).textContent += "(var: "+ old.title + ")";
if (old.body != post.body) {
var diff = Diff.diff_main(old.body, post.body);
Diff.diff_cleanupSemantic(diff);
diff = Diff.diff_prettyHtml(diff);
post.node.innerHTML = diff.replace(/<br>/g, "<br/>");
}
data.ctime = old.ctime;
}
update("diary", data);
}
function init() {
initDB();
GM_addStyle("ins { text-decoration:none; background:darkgreen !important; }" +
"del { text-decoration:none; background:darkred !important; }");
diffDiaryPost();
}
init();
