// Copyright (C) 2013 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.client.diff;
import static com.google.gerrit.client.diff.DisplaySide.A;
import static com.google.gerrit.client.diff.DisplaySide.B;
import static com.google.gerrit.client.diff.OverviewBar.MarkType.DELETE;
import static com.google.gerrit.client.diff.OverviewBar.MarkType.EDIT;
import static com.google.gerrit.client.diff.OverviewBar.MarkType.INSERT;
import com.google.gerrit.client.diff.DiffInfo.Region;
import com.google.gerrit.client.diff.DiffInfo.Span;
import com.google.gerrit.client.rpc.Natives;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsArray;
import com.google.gwt.core.client.JsArrayString;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.EventListener;
import net.codemirror.lib.CodeMirror;
import net.codemirror.lib.CodeMirror.LineClassWhere;
import net.codemirror.lib.Configuration;
import net.codemirror.lib.LineCharacter;
import net.codemirror.lib.LineWidget;
import net.codemirror.lib.TextMarker;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/** Colors modified regions for {@link SideBySide2}. */
class ChunkManager {
private static final JavaScriptObject focusA = initOnClick(A);
private static final JavaScriptObject focusB = initOnClick(B);
private static final native JavaScriptObject initOnClick(DisplaySide s) /*-{
return $entry(function(e){
@com.google.gerrit.client.diff.ChunkManager::focus(
Lcom/google/gwt/dom/client/NativeEvent;
Lcom/google/gerrit/client/diff/DisplaySide;)(e,s)
});
}-*/;
private static void focus(NativeEvent event, DisplaySide side) {
Element e = Element.as(event.getEventTarget());
for (e = DOM.getParent(e); e != null; e = DOM.getParent(e)) {
EventListener l = DOM.getEventListener(e);
if (l instanceof SideBySide2) {
((SideBySide2) l).getCmFromSide(side).focus();
event.stopPropagation();
}
}
};
static void focusOnClick(Element e, DisplaySide side) {
onClick(e, side == A ? focusA : focusB);
}
private static final native void onClick(Element e, JavaScriptObject f)
/*-{ e.onclick = f }-*/;
private final SideBySide2 host;
private final CodeMirror cmA;
private final CodeMirror cmB;
private final OverviewBar sidePanel;
private final LineMapper mapper;
private List<DiffChunkInfo> chunks;
private List<TextMarker> markers;
private List<Runnable> undo;
private List<LineWidget> padding;
ChunkManager(SideBySide2 host,
CodeMirror cmA,
CodeMirror cmB,
OverviewBar sidePanel) {
this.host = host;
this.cmA = cmA;
this.cmB = cmB;
this.sidePanel = sidePanel;
this.mapper = new LineMapper();
}
LineMapper getLineMapper() {
return mapper;
}
DiffChunkInfo getFirst() {
return !chunks.isEmpty() ? chunks.get(0) : null;
}
void reset() {
mapper.reset();
for (TextMarker m : markers) {
m.clear();
}
for (Runnable r : undo) {
r.run();
}
for (LineWidget w : padding) {
w.clear();
}
}
void render(DiffInfo diff) {
chunks = new ArrayList<>();
markers = new ArrayList<>();
undo = new ArrayList<>();
padding = new ArrayList<>();
String diffColor = diff.meta_a() == null || diff.meta_b() == null
? DiffTable.style.intralineBg()
: DiffTable.style.diff();
for (Region current : Natives.asList(diff.content())) {
if (current.ab() != null) {
mapper.appendCommon(current.ab().length());
} else if (current.skip() > 0) {
mapper.appendCommon(current.skip());
} else if (current.common()) {
mapper.appendCommon(current.b().length());
} else {
render(current, diffColor);
}
}
}
private void render(Region region, String diffColor) {
int startA = mapper.getLineA();
int startB = mapper.getLineB();
JsArrayString a = region.a();
JsArrayString b = region.b();
int aLen = a != null ? a.length() : 0;
int bLen = b != null ? b.length() : 0;
String color = a == null || b == null
? diffColor
: DiffTable.style.intralineBg();
colorLines(cmA, color, startA, aLen);
colorLines(cmB, color, startB, bLen);
markEdit(cmA, startA, a, region.edit_a());
markEdit(cmB, startB, b, region.edit_b());
addPadding(cmA, startA + aLen - 1, bLen - aLen);
addPadding(cmB, startB + bLen - 1, aLen - bLen);
addGutterTag(region, startA, startB);
mapper.appendReplace(aLen, bLen);
int endA = mapper.getLineA() - 1;
int endB = mapper.getLineB() - 1;
if (aLen > 0) {
addDiffChunk(cmB, endB, endA, aLen, bLen > 0);
}
if (bLen > 0) {
addDiffChunk(cmA, endA, endB, bLen, aLen > 0);
}
}
private void addGutterTag(Region region, int startA, int startB) {
if (region.a() == null) {
sidePanel.add(cmB, startB, region.b().length(), INSERT);
} else if (region.b() == null) {
sidePanel.add(cmA, startA, region.a().length(), DELETE);
} else {
sidePanel.add(cmB, startB, region.b().length(), EDIT);
}
}
private void markEdit(CodeMirror cm, int startLine,
JsArrayString lines, JsArray<Span> edits) {
if (lines == null || edits == null) {
return;
}
EditIterator iter = new EditIterator(lines, startLine);
Configuration bg = Configuration.create()
.set("className", DiffTable.style.intralineBg())
.set("readOnly", true);
Configuration diff = Configuration.create()
.set("className", DiffTable.style.diff())
.set("readOnly", true);
LineCharacter last = CodeMirror.pos(0, 0);
for (Span span : Natives.asList(edits)) {
LineCharacter from = iter.advance(span.skip());
LineCharacter to = iter.advance(span.mark());
if (from.getLine() == last.getLine()) {
markers.add(cm.markText(last, from, bg));
} else {
markers.add(cm.markText(CodeMirror.pos(from.getLine(), 0), from, bg));
}
markers.add(cm.markText(from, to, diff));
last = to;
colorLines(cm, LineClassWhere.BACKGROUND,
DiffTable.style.diff(),
from.getLine(), to.getLine());
}
}
private void colorLines(CodeMirror cm, String color, int line, int cnt) {
colorLines(cm, LineClassWhere.WRAP, color, line, line + cnt);
}
private void colorLines(final CodeMirror cm, final LineClassWhere where,
final String className, final int start, final int end) {
if (start < end) {
for (int line = start; line < end; line++) {
cm.addLineClass(line, where, className);
}
undo.add(new Runnable() {
@Override
public void run() {
for (int line = start; line < end; line++) {
cm.removeLineClass(line, where, className);
}
}
});
}
}
/**
* Insert a new padding div below the given line.
*
* @param cm parent CodeMirror to add extra space into.
* @param line line to put the padding below.
* @param len number of lines to pad. Padding is inserted only if
* {@code len >= 1}.
*/
private void addPadding(CodeMirror cm, int line, int len) {
if (0 < len) {
// DiffTable adds 1px bottom padding to each line to preserve
// sufficient space for underscores commonly appearing in code.
// Padding should be 1em + 1px high for each line. Add within
// the browser using height + padding-bottom.
Element pad = DOM.createDiv();
pad.setClassName(DiffTable.style.padding());
pad.getStyle().setHeight(len, Unit.EM);
pad.getStyle().setPaddingBottom(len, Unit.PX);
focusOnClick(pad, cm.side());
padding.add(cm.addLineWidget(
line == -1 ? 0 : line,
pad,
Configuration.create()
.set("coverGutter", true)
.set("noHScroll", true)
.set("above", line == -1)));
}
}
private void addDiffChunk(CodeMirror cmToPad, int lineToPad,
int lineOnOther, int chunkSize, boolean edit) {
chunks.add(new DiffChunkInfo(host.otherCm(cmToPad).side(),
lineOnOther - chunkSize + 1, lineOnOther, edit));
}
Runnable diffChunkNav(final CodeMirror cm, final Direction dir) {
return new Runnable() {
@Override
public void run() {
int line = cm.hasActiveLine() ? cm.getLineNumber(cm.getActiveLine()) : 0;
int res = Collections.binarySearch(
chunks,
new DiffChunkInfo(cm.side(), line, 0, false),
getDiffChunkComparator());
if (res < 0) {
res = -res - (dir == Direction.PREV ? 1 : 2);
}
res = res + (dir == Direction.PREV ? -1 : 1);
if (res < 0 || chunks.size() <= res) {
return;
}
DiffChunkInfo lookUp = chunks.get(res);
// If edit, skip the deletion chunk and set focus on the insertion one.
if (lookUp.isEdit() && lookUp.getSide() == A) {
res = res + (dir == Direction.PREV ? -1 : 1);
if (res < 0 || chunks.size() <= res) {
return;
}
}
DiffChunkInfo target = chunks.get(res);
CodeMirror targetCm = host.getCmFromSide(target.getSide());
targetCm.setCursor(LineCharacter.create(target.getStart()));
targetCm.focus();
targetCm.scrollToY(
targetCm.heightAtLine(target.getStart(), "local") -
0.5 * cmB.getScrollbarV().getClientHeight());
}
};
}
private Comparator<DiffChunkInfo> getDiffChunkComparator() {
// Chunks are ordered by their starting line. If it's a deletion,
// use its corresponding line on the revision side for comparison.
// In the edit case, put the deletion chunk right before the
// insertion chunk. This placement guarantees well-ordering.
return new Comparator<DiffChunkInfo>() {
@Override
public int compare(DiffChunkInfo a, DiffChunkInfo b) {
if (a.getSide() == b.getSide()) {
return a.getStart() - b.getStart();
} else if (a.getSide() == A) {
int comp = mapper.lineOnOther(a.getSide(), a.getStart())
.getLine() - b.getStart();
return comp == 0 ? -1 : comp;
} else {
int comp = a.getStart() -
mapper.lineOnOther(b.getSide(), b.getStart()).getLine();
return comp == 0 ? 1 : comp;
}
}
};
}
DiffChunkInfo getDiffChunk(DisplaySide side, int line) {
int res = Collections.binarySearch(
chunks,
new DiffChunkInfo(side, line, 0, false), // Dummy DiffChunkInfo
getDiffChunkComparator());
if (res >= 0) {
return chunks.get(res);
} else { // The line might be within a DiffChunk
res = -res - 1;
if (res > 0) {
DiffChunkInfo info = chunks.get(res - 1);
if (info.getSide() == side && info.getStart() <= line &&
line <= info.getEnd()) {
return info;
}
}
}
return null;
}
}