// Copyright (C) 2009 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.httpd.rpc.patch;
import com.google.gerrit.common.data.CommentDetail;
import com.google.gerrit.common.data.PatchScript;
import com.google.gerrit.common.data.PatchScript.DisplayMethod;
import com.google.gerrit.prettify.common.EditList;
import com.google.gerrit.prettify.common.SparseFileContent;
import com.google.gerrit.reviewdb.client.AccountDiffPreference;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.Patch;
import com.google.gerrit.reviewdb.client.PatchLineComment;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.reviewdb.client.AccountDiffPreference.Whitespace;
import com.google.gerrit.server.FileTypeRegistry;
import com.google.gerrit.server.patch.IntraLineDiff;
import com.google.gerrit.server.patch.IntraLineDiffKey;
import com.google.gerrit.server.patch.PatchListCache;
import com.google.gerrit.server.patch.PatchListEntry;
import com.google.gerrit.server.patch.Text;
import com.google.inject.Inject;
import eu.medsea.mimeutil.MimeType;
import eu.medsea.mimeutil.MimeUtil2;
import org.eclipse.jgit.diff.Edit;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.treewalk.TreeWalk;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
class PatchScriptBuilder {
static final int MAX_CONTEXT = 5000000;
static final int BIG_FILE = 9000;
private static final Comparator<Edit> EDIT_SORT = new Comparator<Edit>() {
@Override
public int compare(final Edit o1, final Edit o2) {
return o1.getBeginA() - o2.getBeginA();
}
};
private Repository db;
private Project.NameKey projectKey;
private ObjectReader reader;
private Change change;
private AccountDiffPreference diffPrefs;
private boolean againstParent;
private ObjectId aId;
private ObjectId bId;
private final Side a;
private final Side b;
private List<Edit> edits;
private final FileTypeRegistry registry;
private final PatchListCache patchListCache;
private int context;
@Inject
PatchScriptBuilder(final FileTypeRegistry ftr, final PatchListCache plc) {
a = new Side();
b = new Side();
registry = ftr;
patchListCache = plc;
}
void setRepository(Repository r, Project.NameKey projectKey) {
this.db = r;
this.projectKey = projectKey;
}
void setChange(final Change c) {
this.change = c;
}
void setDiffPrefs(final AccountDiffPreference dp) {
diffPrefs = dp;
context = diffPrefs.getContext();
if (context == AccountDiffPreference.WHOLE_FILE_CONTEXT) {
context = MAX_CONTEXT;
} else if (context > MAX_CONTEXT) {
context = MAX_CONTEXT;
}
}
void setTrees(final boolean ap, final ObjectId a, final ObjectId b) {
againstParent = ap;
aId = a;
bId = b;
}
PatchScript toPatchScript(final PatchListEntry content,
final CommentDetail comments, final List<Patch> history)
throws IOException {
reader = db.newObjectReader();
try {
return build(content, comments, history);
} finally {
reader.release();
}
}
private PatchScript build(final PatchListEntry content,
final CommentDetail comments, final List<Patch> history)
throws IOException {
boolean intralineDifferenceIsPossible = true;
boolean intralineFailure = false;
a.path = oldName(content);
b.path = newName(content);
a.resolve(null, aId);
b.resolve(a, bId);
edits = new ArrayList<Edit>(content.getEdits());
if (!isModify(content)) {
intralineDifferenceIsPossible = false;
} else if (diffPrefs.isIntralineDifference()) {
IntraLineDiff d =
patchListCache.getIntraLineDiff(new IntraLineDiffKey(a.id, a.src,
b.id, b.src, edits, projectKey, bId, b.path));
if (d != null) {
switch (d.getStatus()) {
case EDIT_LIST:
edits = new ArrayList<Edit>(d.getEdits());
break;
case DISABLED:
intralineDifferenceIsPossible = false;
break;
case ERROR:
case TIMEOUT:
intralineDifferenceIsPossible = false;
intralineFailure = true;
break;
}
} else {
intralineDifferenceIsPossible = false;
intralineFailure = true;
}
}
ensureCommentsVisible(comments);
boolean hugeFile = false;
if (a.mode == FileMode.GITLINK || b.mode == FileMode.GITLINK) {
} else if (a.src == b.src && a.size() <= context
&& content.getEdits().isEmpty()) {
// Odd special case; the files are identical (100% rename or copy)
// and the user has asked for context that is larger than the file.
// Send them the entire file, with an empty edit after the last line.
//
for (int i = 0; i < a.size(); i++) {
a.addLine(i);
}
edits = new ArrayList<Edit>(1);
edits.add(new Edit(a.size(), a.size()));
} else {
if (BIG_FILE < Math.max(a.size(), b.size())) {
// IF the file is really large, we disable things to avoid choking
// the browser client.
//
diffPrefs.setContext((short) Math.min(25, context));
diffPrefs.setSyntaxHighlighting(false);
context = diffPrefs.getContext();
hugeFile = true;
} else if (diffPrefs.isSyntaxHighlighting()) {
// In order to syntax highlight the file properly we need to
// give the client the complete file contents. So force our
// context temporarily to the complete file size.
//
context = MAX_CONTEXT;
}
packContent(diffPrefs.getIgnoreWhitespace() != Whitespace.IGNORE_NONE);
}
return new PatchScript(change.getKey(), content.getChangeType(),
content.getOldName(), content.getNewName(), a.fileMode, b.fileMode,
content.getHeaderLines(), diffPrefs, a.dst, b.dst, edits,
a.displayMethod, b.displayMethod, comments, history, hugeFile,
intralineDifferenceIsPossible, intralineFailure);
}
private static boolean isModify(PatchListEntry content) {
switch (content.getChangeType()) {
case MODIFIED:
case COPIED:
case RENAMED:
return true;
case ADDED:
case DELETED:
default:
return false;
}
}
private static String oldName(final PatchListEntry entry) {
switch (entry.getChangeType()) {
case ADDED:
return null;
case DELETED:
case MODIFIED:
return entry.getNewName();
case COPIED:
case RENAMED:
default:
return entry.getOldName();
}
}
private static String newName(final PatchListEntry entry) {
switch (entry.getChangeType()) {
case DELETED:
return null;
case ADDED:
case MODIFIED:
case COPIED:
case RENAMED:
default:
return entry.getNewName();
}
}
private void ensureCommentsVisible(final CommentDetail comments) {
if (comments.getCommentsA().isEmpty() && comments.getCommentsB().isEmpty()) {
// No comments, no additional dummy edits are required.
//
return;
}
// Construct empty Edit blocks around each location where a comment is.
// This will force the later packContent method to include the regions
// containing comments, potentially combining those regions together if
// they have overlapping contexts. UI renders will also be able to make
// correct hunks from this, but because the Edit is empty they will not
// style it specially.
//
final List<Edit> empty = new ArrayList<Edit>();
int lastLine;
lastLine = -1;
for (PatchLineComment plc : comments.getCommentsA()) {
final int a = plc.getLine();
if (lastLine != a) {
final int b = mapA2B(a - 1);
if (0 <= b) {
safeAdd(empty, new Edit(a - 1, b));
}
lastLine = a;
}
}
lastLine = -1;
for (PatchLineComment plc : comments.getCommentsB()) {
final int b = plc.getLine();
if (lastLine != b) {
final int a = mapB2A(b - 1);
if (0 <= a) {
safeAdd(empty, new Edit(a, b - 1));
}
lastLine = b;
}
}
// Sort the final list by the index in A, so packContent can combine
// them correctly later.
//
edits.addAll(empty);
Collections.sort(edits, EDIT_SORT);
}
private void safeAdd(final List<Edit> empty, final Edit toAdd) {
final int a = toAdd.getBeginA();
final int b = toAdd.getBeginB();
for (final Edit e : edits) {
if (e.getBeginA() <= a && a <= e.getEndA()) {
return;
}
if (e.getBeginB() <= b && b <= e.getEndB()) {
return;
}
}
empty.add(toAdd);
}
private int mapA2B(final int a) {
if (edits.isEmpty()) {
// Magic special case of an unmodified file.
//
return a;
}
for (int i = 0; i < edits.size(); i++) {
final Edit e = edits.get(i);
if (a < e.getBeginA()) {
if (i == 0) {
// Special case of context at start of file.
//
return a;
}
return e.getBeginB() - (e.getBeginA() - a);
}
if (e.getBeginA() <= a && a <= e.getEndA()) {
return -1;
}
}
final Edit last = edits.get(edits.size() - 1);
return last.getBeginB() + (a - last.getEndA());
}
private int mapB2A(final int b) {
if (edits.isEmpty()) {
// Magic special case of an unmodified file.
//
return b;
}
for (int i = 0; i < edits.size(); i++) {
final Edit e = edits.get(i);
if (b < e.getBeginB()) {
if (i == 0) {
// Special case of context at start of file.
//
return b;
}
return e.getBeginA() - (e.getBeginB() - b);
}
if (e.getBeginB() <= b && b <= e.getEndB()) {
return -1;
}
}
final Edit last = edits.get(edits.size() - 1);
return last.getBeginA() + (b - last.getEndB());
}
private void packContent(boolean ignoredWhitespace) {
EditList list = new EditList(edits, context, a.size(), b.size());
for (final EditList.Hunk hunk : list.getHunks()) {
while (hunk.next()) {
if (hunk.isContextLine()) {
final String lineA = a.src.getString(hunk.getCurA());
a.dst.addLine(hunk.getCurA(), lineA);
if (ignoredWhitespace) {
// If we ignored whitespace in some form, also get the line
// from b when it does not exactly match the line from a.
//
final String lineB = b.src.getString(hunk.getCurB());
if (!lineA.equals(lineB)) {
b.dst.addLine(hunk.getCurB(), lineB);
}
}
hunk.incBoth();
continue;
}
if (hunk.isDeletedA()) {
a.addLine(hunk.getCurA());
hunk.incA();
}
if (hunk.isInsertedB()) {
b.addLine(hunk.getCurB());
hunk.incB();
}
}
}
}
private class Side {
String path;
ObjectId id;
FileMode mode;
byte[] srcContent;
Text src;
MimeType mimeType = MimeUtil2.UNKNOWN_MIME_TYPE;
DisplayMethod displayMethod = DisplayMethod.DIFF;
PatchScript.FileMode fileMode = PatchScript.FileMode.FILE;
final SparseFileContent dst = new SparseFileContent();
int size() {
return src != null ? src.size() : 0;
}
void addLine(int line) {
dst.addLine(line, src.getString(line));
}
void resolve(final Side other, final ObjectId within) throws IOException {
try {
final boolean reuse;
if (Patch.COMMIT_MSG.equals(path)) {
if (againstParent && (aId == within || within.equals(aId))) {
id = ObjectId.zeroId();
src = Text.EMPTY;
srcContent = Text.NO_BYTES;
mode = FileMode.MISSING;
displayMethod = DisplayMethod.NONE;
} else {
id = within;
src = Text.forCommit(db, reader, within);
srcContent = src.getContent();
if (src == Text.EMPTY) {
mode = FileMode.MISSING;
displayMethod = DisplayMethod.NONE;
} else {
mode = FileMode.REGULAR_FILE;
}
}
reuse = false;
} else {
final TreeWalk tw = find(within);
id = tw != null ? tw.getObjectId(0) : ObjectId.zeroId();
mode = tw != null ? tw.getFileMode(0) : FileMode.MISSING;
reuse = other != null && other.id.equals(id) && other.mode == mode;
if (reuse) {
srcContent = other.srcContent;
} else if (mode.getObjectType() == Constants.OBJ_BLOB) {
srcContent = Text.asByteArray(db.open(id, Constants.OBJ_BLOB));
} else {
srcContent = Text.NO_BYTES;
}
if (reuse) {
mimeType = other.mimeType;
displayMethod = other.displayMethod;
src = other.src;
} else if (srcContent.length > 0 && FileMode.SYMLINK != mode) {
mimeType = registry.getMimeType(path, srcContent);
if ("image".equals(mimeType.getMediaType())
&& registry.isSafeInline(mimeType)) {
displayMethod = DisplayMethod.IMG;
}
}
}
if (mode == FileMode.MISSING) {
displayMethod = DisplayMethod.NONE;
}
if (!reuse) {
if (srcContent == Text.NO_BYTES) {
src = Text.EMPTY;
} else {
src = new Text(srcContent);
}
}
if (srcContent.length > 0 && srcContent[srcContent.length - 1] != '\n') {
dst.setMissingNewlineAtEnd(true);
}
dst.setSize(size());
dst.setPath(path);
if (mode == FileMode.SYMLINK) {
fileMode = PatchScript.FileMode.SYMLINK;
} else if (mode == FileMode.GITLINK) {
fileMode = PatchScript.FileMode.GITLINK;
}
} catch (IOException err) {
throw new IOException("Cannot read " + within.name() + ":" + path, err);
}
}
private TreeWalk find(final ObjectId within) throws MissingObjectException,
IncorrectObjectTypeException, CorruptObjectException, IOException {
if (path == null || within == null) {
return null;
}
final RevWalk rw = new RevWalk(reader);
final RevTree tree = rw.parseTree(within);
return TreeWalk.forPath(reader, path, tree);
}
}
}