java/com/google/gerrit/server/notedb/ChangeNoteUtil.java - gerrit - Git at Google

 // 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.server.notedb;

 import com.google.auto.value.AutoValue;
 import com.google.common.base.Splitter;
 import com.google.common.base.Strings;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.AttentionSetUpdate;
 import com.google.gerrit.json.OutputFormat;
 import com.google.gerrit.server.config.GerritServerId;
 import com.google.gson.Gson;
 import com.google.inject.Inject;
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 import org.eclipse.jgit.errors.ConfigInvalidException;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.revwalk.FooterKey;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.util.RawParseUtils;

 public class ChangeNoteUtil {

   public static final FooterKey FOOTER_ATTENTION = new FooterKey("Attention");
   public static final FooterKey FOOTER_ASSIGNEE = new FooterKey("Assignee");
   public static final FooterKey FOOTER_BRANCH = new FooterKey("Branch");
   public static final FooterKey FOOTER_CHANGE_ID = new FooterKey("Change-id");
   public static final FooterKey FOOTER_COMMIT = new FooterKey("Commit");
   public static final FooterKey FOOTER_CURRENT = new FooterKey("Current");
   public static final FooterKey FOOTER_GROUPS = new FooterKey("Groups");
   public static final FooterKey FOOTER_HASHTAGS = new FooterKey("Hashtags");
   public static final FooterKey FOOTER_LABEL = new FooterKey("Label");
   public static final FooterKey FOOTER_COPIED_LABEL = new FooterKey("Copied-Label");
   public static final FooterKey FOOTER_PATCH_SET = new FooterKey("Patch-set");
   public static final FooterKey FOOTER_PATCH_SET_DESCRIPTION =
       new FooterKey("Patch-set-description");
   public static final FooterKey FOOTER_PRIVATE = new FooterKey("Private");
   public static final FooterKey FOOTER_REAL_USER = new FooterKey("Real-user");
   public static final FooterKey FOOTER_STATUS = new FooterKey("Status");
   public static final FooterKey FOOTER_SUBJECT = new FooterKey("Subject");
   public static final FooterKey FOOTER_SUBMISSION_ID = new FooterKey("Submission-id");
   public static final FooterKey FOOTER_SUBMITTED_WITH = new FooterKey("Submitted-with");
   public static final FooterKey FOOTER_TOPIC = new FooterKey("Topic");
   public static final FooterKey FOOTER_TAG = new FooterKey("Tag");
   public static final FooterKey FOOTER_WORK_IN_PROGRESS = new FooterKey("Work-in-progress");
   public static final FooterKey FOOTER_REVERT_OF = new FooterKey("Revert-of");
   public static final FooterKey FOOTER_CHERRY_PICK_OF = new FooterKey("Cherry-pick-of");

   static final String GERRIT_USER_TEMPLATE = "Gerrit User %d";

   private static final Gson gson = OutputFormat.JSON_COMPACT.newGson();
   private static final String LABEL_VOTE_UUID_SEPARATOR = ", ";

   private final ChangeNoteJson changeNoteJson;
   private final String serverId;

   @Inject
   public ChangeNoteUtil(ChangeNoteJson changeNoteJson, @GerritServerId String serverId) {
     this.serverId = serverId;
     this.changeNoteJson = changeNoteJson;
   }

   public ChangeNoteJson getChangeNoteJson() {
     return changeNoteJson;
   }

   /**
    * Generates a user identifier that contains the account ID, but not the user's name or email
    * address.
    *
    * @return The passed in {@link StringBuilder} instance to which the identifier has been appended.
    */
   StringBuilder appendAccountIdIdentString(StringBuilder stringBuilder, Account.Id accountId) {
     return stringBuilder
         .append(getAccountIdAsUsername(accountId))
         .append(" <")
         .append(getAccountIdAsEmailAddress(accountId))
         .append('>');
   }

   public static String formatAccountIdentString(Account.Id account, String accountIdAsEmail) {
     return String.format(
         "%s <%s>", ChangeNoteUtil.getAccountIdAsUsername(account), accountIdAsEmail);
   }

   /**
    * Returns a {@link PersonIdent} that contains the account ID, but not the user's name or email
    * address.
    */
   public PersonIdent newAccountIdIdent(
       Account.Id accountId, Instant when, PersonIdent serverIdent) {
     return new PersonIdent(
         getAccountIdAsUsername(accountId),
         getAccountIdAsEmailAddress(accountId),
         when,
         serverIdent.getZoneId());
   }

   /** Returns the string {@code "Gerrit User " + accountId}, to pseudonymize user names. */
   public static String getAccountIdAsUsername(Account.Id accountId) {
     return String.format(GERRIT_USER_TEMPLATE, accountId.get());
   }

   public String getAccountIdAsEmailAddress(Account.Id accountId) {
     return accountId.get() + "@" + serverId;
   }

   public static Optional<CommitMessageRange> parseCommitMessageRange(RevCommit commit) {
     byte[] raw = commit.getRawBuffer();
     int size = raw.length;

     int subjectStart = RawParseUtils.commitMessage(raw, 0);
     if (subjectStart < 0 || subjectStart >= size) {
       return Optional.empty();
     }

     int subjectEnd = RawParseUtils.endOfParagraph(raw, subjectStart);
     if (subjectEnd == size) {
       return Optional.empty();
     }

     int changeMessageStart;

     if (raw[subjectEnd] == '\n') {
       changeMessageStart = subjectEnd + 2; // \n\n ends paragraph
     } else if (raw[subjectEnd] == '\r') {
       changeMessageStart = subjectEnd + 4; // \r\n\r\n ends paragraph
     } else {
       return Optional.empty();
     }

     int ptr = size - 1;
     int changeMessageEnd = -1;
     while (ptr > changeMessageStart) {
       ptr = RawParseUtils.prevLF(raw, ptr, '\r');
       if (ptr == -1) {
         break;
       }
       if (raw[ptr] == '\n') {
         changeMessageEnd = ptr - 1;
         break;
       } else if (raw[ptr] == '\r') {
         changeMessageEnd = ptr - 3;
         break;
       }
     }

     if (ptr <= changeMessageStart) {
       // Return with subject, ChangeMessage is empty
       return Optional.of(
           CommitMessageRange.builder()
               .subjectStart(subjectStart)
               .subjectEnd(subjectEnd)
               .changeMessageStart(changeMessageStart)
               .changeMessageEnd(changeMessageStart)
               .build());
     }

     CommitMessageRange range =
         CommitMessageRange.builder()
             .subjectStart(subjectStart)
             .subjectEnd(subjectEnd)
             .changeMessageStart(changeMessageStart)
             .changeMessageEnd(changeMessageEnd)
             .build();

     return Optional.of(range);
   }

   @AutoValue
   public abstract static class CommitMessageRange {

     public abstract int subjectStart();

     public abstract int subjectEnd();

     public abstract int changeMessageStart();

     public abstract int changeMessageEnd();

     public boolean hasChangeMessage() {
       return changeMessageStart() < changeMessageEnd();
     }

     public static Builder builder() {
       return new AutoValue_ChangeNoteUtil_CommitMessageRange.Builder();
     }

     @AutoValue.Builder
     public abstract static class Builder {

       abstract Builder subjectStart(int subjectStart);

       abstract Builder subjectEnd(int subjectEnd);

       abstract Builder changeMessageStart(int changeMessageStart);

       abstract Builder changeMessageEnd(int changeMessageEnd);

       abstract CommitMessageRange build();
     }
   }

   /** Helper class for JSON serialization. Timestamp is taken from the commit. */
   public static class AttentionStatusInNoteDb {

     final String personIdent;
     final AttentionSetUpdate.Operation operation;
     final String reason;

     AttentionStatusInNoteDb(
         String personIndent, AttentionSetUpdate.Operation operation, String reason) {
       this.personIdent = personIndent;
       this.operation = operation;
       this.reason = reason;
     }
   }

   /** The returned {@link Optional} holds the parsed entity or is empty if parsing failed. */
   static Optional<AttentionSetUpdate> attentionStatusFromJson(
       Instant timestamp, String attentionString) {
     AttentionStatusInNoteDb inNoteDb =
         gson.fromJson(attentionString, AttentionStatusInNoteDb.class);
     PersonIdent personIdent = RawParseUtils.parsePersonIdent(inNoteDb.personIdent);
     if (personIdent == null) {
       return Optional.empty();
     }
     Optional<Account.Id> account = NoteDbUtil.parseIdent(personIdent);
     return account.map(
         id ->
             AttentionSetUpdate.createFromRead(timestamp, id, inNoteDb.operation, inNoteDb.reason));
   }

   String attentionSetUpdateToJson(AttentionSetUpdate attentionSetUpdate) {
     StringBuilder stringBuilder = new StringBuilder();
     appendAccountIdIdentString(stringBuilder, attentionSetUpdate.account());
     return gson.toJson(
         new AttentionStatusInNoteDb(
             stringBuilder.toString(), attentionSetUpdate.operation(), attentionSetUpdate.reason()));
   }

   /**
    * {@link com.google.gerrit.entities.PatchSetApproval}, parsed from {@link #FOOTER_LABEL} or
    * {@link #FOOTER_COPIED_LABEL}.
    *
    * <p>In comparison to {@link com.google.gerrit.entities.PatchSetApproval}, this entity represent
    * the raw fields, parsed from the NoteDB footer line, without any interpretation of the parsed
    * values. See {@link #parseApproval} and {@link #parseCopiedApproval} for the valid {@link
    * #footerLine} values.
    */
   @AutoValue
   public abstract static class ParsedPatchSetApproval {

     /** The original footer value, that this entity was parsed from. */
     public abstract String footerLine();

     public abstract boolean isRemoval();

     /** Either <LABEL>=VOTE or <LABEL> for {@link #isRemoval}. */
     public abstract String labelVote();

     public abstract Optional<String> uuid();

     public abstract Optional<String> accountIdent();

     public abstract Optional<String> realAccountIdent();

     public abstract Optional<String> tag();

     public static Builder builder() {
       return new AutoValue_ChangeNoteUtil_ParsedPatchSetApproval.Builder();
     }

     @AutoValue.Builder
     public abstract static class Builder {

       abstract Builder footerLine(String labelLine);

       abstract Builder isRemoval(boolean isRemoval);

       abstract Builder labelVote(String labelVote);

       abstract Builder uuid(Optional<String> uuid);

       abstract Builder accountIdent(Optional<String> accountIdent);

       abstract Builder realAccountIdent(Optional<String> realAccountIdent);

       abstract Builder tag(Optional<String> tag);

       abstract ParsedPatchSetApproval build();
     }
   }

   /**
    * Delegates parsing of {@link ParsedPatchSetApproval} from {@link #FOOTER_LABEL} line to
    * dedicated methods: {@link #parseAddedApproval} and {@link #parseRemovedApproval}
    * correspondingly.
    */
   public static ParsedPatchSetApproval parseApproval(String footerLine)
       throws ConfigInvalidException {
     try {
       return footerLine.startsWith("-")
           ? parseRemovedApproval(footerLine)
           : parseAddedApproval(footerLine);
     } catch (StringIndexOutOfBoundsException ex) {
       throw parseException(FOOTER_LABEL, footerLine, ex);
     }
   }

   /**
    * Parses added {@link ParsedPatchSetApproval} from {@link #FOOTER_LABEL} line.
    *
    * <p>Valid added approval footer examples:
    *
    * <ul>
    *   <li>Label: &lt;LABEL&gt;=VOTE
    *   <li>Label: &lt;LABEL&gt;=VOTE &lt;Gerrit Account&gt;
    *   <li>Label: &lt;LABEL&gt;=VOTE, &lt;UUID&gt;
    *   <li>Label: &lt;LABEL&gt;=VOTE, &lt;UUID&gt; &lt;Gerrit Account&gt;
    * </ul>
    *
    * <p>&lt;UUID&gt; is optional, since the approval might have been granted before {@link
    * com.google.gerrit.entities.PatchSetApproval.UUID} was introduced.
    *
    * <p><Gerrit Account> is only persisted in cases, when the account, that granted the vote does
    * not match the account, that issued {@link ChangeUpdate} (created this NoteDB commit).
    */
   private static ParsedPatchSetApproval parseAddedApproval(String footerLine)
       throws ConfigInvalidException {
     ParsedPatchSetApproval.Builder rawPatchSetApproval =
         ParsedPatchSetApproval.builder().footerLine(footerLine);
     rawPatchSetApproval.isRemoval(false);
     // We need some additional logic to differentiate between labels that have a UUID and those that
     // have a user with a comma. This allows us to separate the following cases (note that the
     // leading `Label: ` has been elided at this point):
     //   Label: <LABEL>=VOTE, <UUID> <Gerrit Account>
     //   Label: <LABEL>=VOTE <Gerrit, Account>
     int reviewerStartOffset = 0;
     int scoreStart = footerLine.indexOf('=') + 1;
     StringBuilder labelNameScore = new StringBuilder(footerLine.substring(0, scoreStart));
     for (int i = scoreStart; i < footerLine.length(); i++) {
       char currentChar = footerLine.charAt(i);

       // If we hit ',' before ' ' we have a UUID
       if (currentChar == ',') {
         labelNameScore.append(footerLine, scoreStart, i);
         int uuidStart = i + LABEL_VOTE_UUID_SEPARATOR.length();
         int uuidEnd = footerLine.indexOf(' ', uuidStart);
         String uuid = footerLine.substring(uuidStart, uuidEnd > 0 ? uuidEnd : footerLine.length());
         checkFooter(!Strings.isNullOrEmpty(uuid), FOOTER_LABEL, footerLine);
         rawPatchSetApproval.uuid(Optional.of(uuid));
         reviewerStartOffset = uuidStart + uuid.length();
         break;
       }

       // Otherwise we don't
       if (currentChar == ' ') {
         labelNameScore.append(footerLine, scoreStart, i);
         break;
       }

       // If we hit neither we're defensive assign the whole line
       if (i == footerLine.length() - 1) {
         labelNameScore = new StringBuilder(footerLine);
         break;
       }
     }

     rawPatchSetApproval.labelVote(labelNameScore.toString());

     int reviewerStart = footerLine.indexOf(' ', reviewerStartOffset);
     if (reviewerStart > 0) {
       String ident = footerLine.substring(reviewerStart + 1);
       rawPatchSetApproval.accountIdent(Optional.of(ident));
     }
     return rawPatchSetApproval.build();
   }

   /**
    * Parses removed {@link ParsedPatchSetApproval} from {@link #FOOTER_LABEL} line.
    *
    * <p>Valid removed approval footer examples:
    *
    * <ul>
    *   <li>-&lt;LABEL&gt;
    *   <li>-&lt;LABEL&gt; &lt;Gerrit Account&gt;
    * </ul>
    *
    * <p>&lt;Gerrit Account&gt; is only persisted in cases, when the account, that granted the vote
    * does not match the account, that issued {@link ChangeUpdate} (created this NoteDB commit).
    */
   private static ParsedPatchSetApproval parseRemovedApproval(String footerLine) {
     ParsedPatchSetApproval.Builder rawPatchSetApproval =
         ParsedPatchSetApproval.builder().footerLine(footerLine);
     rawPatchSetApproval.isRemoval(true);
     int labelStart = 1;
     int reviewerStart = footerLine.indexOf(' ', labelStart);

     rawPatchSetApproval.labelVote(
         reviewerStart != -1
             ? footerLine.substring(labelStart, reviewerStart)
             : footerLine.substring(labelStart));

     if (reviewerStart > 0) {
       String ident = footerLine.substring(reviewerStart + 1);
       rawPatchSetApproval.accountIdent(Optional.of(ident));
     }
     return rawPatchSetApproval.build();
   }

   /**
    * Parses copied {@link ParsedPatchSetApproval} from {@link #FOOTER_COPIED_LABEL} line.
    *
    * <p>Footer example: Copied-Label: <LABEL>=VOTE, <UUID> <Gerrit Account>,<Gerrit Real Account>
    * :"<TAG>"
    *
    * <ul>
    *   <li>":<"TAG>"" is optional.
    *   <li><Gerrit Real Account> is also optional, if it was not set.
    *   <li><UUID> is optional, since the approval might have been granted before {@link
    *       com.google.gerrit.entities.PatchSetApproval.UUID} was introduced.
    *   <li>The label, vote, and the Gerrit account are mandatory (unlike FOOTER_LABEL where Gerrit
    *       Account is also optional since by default it's the committer).
    * </ul>
    */
   public static ParsedPatchSetApproval parseCopiedApproval(String labelLine)
       throws ConfigInvalidException {
     try {
       // Copied approvals can't be explicitly removed. They are removed the same way as non-copied
       // approvals.
       checkFooter(!labelLine.startsWith("-"), FOOTER_COPIED_LABEL, labelLine);
       ParsedPatchSetApproval.Builder rawPatchSetApproval =
           ParsedPatchSetApproval.builder().footerLine(labelLine).isRemoval(false);

       int tagStart = labelLine.indexOf(":\"");
       int uuidStart = parseCopiedApprovalUuidStart(labelLine, tagStart);

       // Weird tag that contains uuid delimiter. The uuid is actually not present.
       if (tagStart != -1 && uuidStart > tagStart) {
         uuidStart = -1;
       }

       int identitiesStart =
           labelLine.indexOf(
               ' ', uuidStart != -1 ? uuidStart + LABEL_VOTE_UUID_SEPARATOR.length() : 0);
       checkFooter(
           identitiesStart != -1 && identitiesStart < labelLine.length(),
           FOOTER_COPIED_LABEL,
           labelLine);

       String labelVoteStr = labelLine.substring(0, uuidStart != -1 ? uuidStart : identitiesStart);
       rawPatchSetApproval.labelVote(labelVoteStr);
       if (uuidStart != -1) {
         String uuid = labelLine.substring(uuidStart + 2, identitiesStart);
         checkFooter(!Strings.isNullOrEmpty(uuid), FOOTER_COPIED_LABEL, labelLine);
         rawPatchSetApproval.uuid(Optional.of(uuid));
       }
       // The first account is the accountId, and second (if applicable) is the realAccountId.
       List<String> identities =
           parseIdentities(
               labelLine.substring(
                   identitiesStart + 1, tagStart == -1 ? labelLine.length() : tagStart));
       checkFooter(identities.size() >= 1, FOOTER_COPIED_LABEL, labelLine);

       rawPatchSetApproval.accountIdent(Optional.of(identities.get(0)));

       if (identities.size() > 1) {
         rawPatchSetApproval.realAccountIdent(Optional.of(identities.get(1)));
       }

       if (tagStart != -1) {
         // tagStart+2 skips ":\"" to parse the actual tag. Tags are in brackets.
         // line.length()-1 skips the last ".
         String tag = labelLine.substring(tagStart + 2, labelLine.length() - 1);
         rawPatchSetApproval.tag(Optional.of(tag));
       }
       return rawPatchSetApproval.build();
     } catch (StringIndexOutOfBoundsException ex) {
       throw parseException(FOOTER_COPIED_LABEL, labelLine, ex);
     }
   }

   // Return the UUID start index or -1 if no UUID is present
   private static int parseCopiedApprovalUuidStart(String line, int tagStart) {
     int separatorIndex = line.indexOf(LABEL_VOTE_UUID_SEPARATOR);

     // The first part of the condition checks whether the footer has the following format:
     //   Copied-Label: <LABEL>=VOTE <Gerrit Account>,<Gerrit Real Account> :"<TAG>"
     //   Weird tag that contains uuid delimiter. The uuid is actually not present.
     if ((tagStart != -1 && separatorIndex > tagStart)
         ||

         // The second part of the condition allows us to distinguish the following two lines:
         //   Label2=+1, 577fb248e474018276351785930358ec0450e9f7 Gerrit User 1 <1@gerrit>
         //   Label2=+1 User Name (company_name, department) <2@gerrit>
         (line.indexOf(' ') < separatorIndex)) {
       return -1;
     }
     return separatorIndex;
   }

   // Splitting on "," breaks for identities containing commas. The below re-implements splitting on
   // "(?<=>),", but it's 3-5x faster, as performance matters here.
   private static List<String> parseIdentities(String line) {
     List<String> idents = Splitter.on(',').splitToList(line);
     List<String> identitiesList = new ArrayList<>();
     for (int i = 0; i < idents.size(); i++) {
       if (i == 0 || idents.get(i - 1).endsWith(">")) {
         identitiesList.add(idents.get(i));
       } else {
         int lastIndex = identitiesList.size() - 1;
         identitiesList.set(lastIndex, identitiesList.get(lastIndex) + "," + idents.get(i));
       }
     }
     return identitiesList;
   }

   private static void checkFooter(boolean expr, FooterKey footer, String actual)
       throws ConfigInvalidException {
     if (!expr) {
       throw parseException(footer, actual, /*cause=*/ null);
     }
   }

   private static ConfigInvalidException parseException(
       FooterKey footer, String actual, Throwable cause) {
     return new ConfigInvalidException(
         String.format("invalid %s: %s", footer.getName(), actual), cause);
   }
 }
	// 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.server.notedb;

	import com.google.auto.value.AutoValue;
	import com.google.common.base.Splitter;
	import com.google.common.base.Strings;
	import com.google.gerrit.entities.Account;
	import com.google.gerrit.entities.AttentionSetUpdate;
	import com.google.gerrit.json.OutputFormat;
	import com.google.gerrit.server.config.GerritServerId;
	import com.google.gson.Gson;
	import com.google.inject.Inject;
	import java.time.Instant;
	import java.util.ArrayList;
	import java.util.List;
	import java.util.Optional;
	import org.eclipse.jgit.errors.ConfigInvalidException;
	import org.eclipse.jgit.lib.PersonIdent;
	import org.eclipse.jgit.revwalk.FooterKey;
	import org.eclipse.jgit.revwalk.RevCommit;
	import org.eclipse.jgit.util.RawParseUtils;

	public class ChangeNoteUtil {

	public static final FooterKey FOOTER_ATTENTION = new FooterKey("Attention");
	public static final FooterKey FOOTER_ASSIGNEE = new FooterKey("Assignee");
	public static final FooterKey FOOTER_BRANCH = new FooterKey("Branch");
	public static final FooterKey FOOTER_CHANGE_ID = new FooterKey("Change-id");
	public static final FooterKey FOOTER_COMMIT = new FooterKey("Commit");
	public static final FooterKey FOOTER_CURRENT = new FooterKey("Current");
	public static final FooterKey FOOTER_GROUPS = new FooterKey("Groups");
	public static final FooterKey FOOTER_HASHTAGS = new FooterKey("Hashtags");
	public static final FooterKey FOOTER_LABEL = new FooterKey("Label");
	public static final FooterKey FOOTER_COPIED_LABEL = new FooterKey("Copied-Label");
	public static final FooterKey FOOTER_PATCH_SET = new FooterKey("Patch-set");
	public static final FooterKey FOOTER_PATCH_SET_DESCRIPTION =
	new FooterKey("Patch-set-description");
	public static final FooterKey FOOTER_PRIVATE = new FooterKey("Private");
	public static final FooterKey FOOTER_REAL_USER = new FooterKey("Real-user");
	public static final FooterKey FOOTER_STATUS = new FooterKey("Status");
	public static final FooterKey FOOTER_SUBJECT = new FooterKey("Subject");
	public static final FooterKey FOOTER_SUBMISSION_ID = new FooterKey("Submission-id");
	public static final FooterKey FOOTER_SUBMITTED_WITH = new FooterKey("Submitted-with");
	public static final FooterKey FOOTER_TOPIC = new FooterKey("Topic");
	public static final FooterKey FOOTER_TAG = new FooterKey("Tag");
	public static final FooterKey FOOTER_WORK_IN_PROGRESS = new FooterKey("Work-in-progress");
	public static final FooterKey FOOTER_REVERT_OF = new FooterKey("Revert-of");
	public static final FooterKey FOOTER_CHERRY_PICK_OF = new FooterKey("Cherry-pick-of");

	static final String GERRIT_USER_TEMPLATE = "Gerrit User %d";

	private static final Gson gson = OutputFormat.JSON_COMPACT.newGson();
	private static final String LABEL_VOTE_UUID_SEPARATOR = ", ";

	private final ChangeNoteJson changeNoteJson;
	private final String serverId;

	@Inject
	public ChangeNoteUtil(ChangeNoteJson changeNoteJson, @GerritServerId String serverId) {
	this.serverId = serverId;
	this.changeNoteJson = changeNoteJson;
	}

	public ChangeNoteJson getChangeNoteJson() {
	return changeNoteJson;
	}

	/**
	* Generates a user identifier that contains the account ID, but not the user's name or email
	* address.
	*
	* @return The passed in {@link StringBuilder} instance to which the identifier has been appended.
	*/
	StringBuilder appendAccountIdIdentString(StringBuilder stringBuilder, Account.Id accountId) {
	return stringBuilder
	.append(getAccountIdAsUsername(accountId))
	.append(" <")
	.append(getAccountIdAsEmailAddress(accountId))
	.append('>');
	}

	public static String formatAccountIdentString(Account.Id account, String accountIdAsEmail) {
	return String.format(
	"%s <%s>", ChangeNoteUtil.getAccountIdAsUsername(account), accountIdAsEmail);
	}

	/**
	* Returns a {@link PersonIdent} that contains the account ID, but not the user's name or email
	* address.
	*/
	public PersonIdent newAccountIdIdent(
	Account.Id accountId, Instant when, PersonIdent serverIdent) {
	return new PersonIdent(
	getAccountIdAsUsername(accountId),
	getAccountIdAsEmailAddress(accountId),
	when,
	serverIdent.getZoneId());
	}

	/** Returns the string {@code "Gerrit User " + accountId}, to pseudonymize user names. */
	public static String getAccountIdAsUsername(Account.Id accountId) {
	return String.format(GERRIT_USER_TEMPLATE, accountId.get());
	}

	public String getAccountIdAsEmailAddress(Account.Id accountId) {
	return accountId.get() + "@" + serverId;
	}

	public static Optional<CommitMessageRange> parseCommitMessageRange(RevCommit commit) {
	byte[] raw = commit.getRawBuffer();
	int size = raw.length;

	int subjectStart = RawParseUtils.commitMessage(raw, 0);
	if (subjectStart < 0 \|\| subjectStart >= size) {
	return Optional.empty();
	}

	int subjectEnd = RawParseUtils.endOfParagraph(raw, subjectStart);
	if (subjectEnd == size) {
	return Optional.empty();
	}

	int changeMessageStart;

	if (raw[subjectEnd] == '\n') {
	changeMessageStart = subjectEnd + 2; // \n\n ends paragraph
	} else if (raw[subjectEnd] == '\r') {
	changeMessageStart = subjectEnd + 4; // \r\n\r\n ends paragraph
	} else {
	return Optional.empty();
	}

	int ptr = size - 1;
	int changeMessageEnd = -1;
	while (ptr > changeMessageStart) {
	ptr = RawParseUtils.prevLF(raw, ptr, '\r');
	if (ptr == -1) {
	break;
	}
	if (raw[ptr] == '\n') {
	changeMessageEnd = ptr - 1;
	break;
	} else if (raw[ptr] == '\r') {
	changeMessageEnd = ptr - 3;
	break;
	}
	}

	if (ptr <= changeMessageStart) {
	// Return with subject, ChangeMessage is empty
	return Optional.of(
	CommitMessageRange.builder()
	.subjectStart(subjectStart)
	.subjectEnd(subjectEnd)
	.changeMessageStart(changeMessageStart)
	.changeMessageEnd(changeMessageStart)
	.build());
	}

	CommitMessageRange range =
	CommitMessageRange.builder()
	.subjectStart(subjectStart)
	.subjectEnd(subjectEnd)
	.changeMessageStart(changeMessageStart)
	.changeMessageEnd(changeMessageEnd)
	.build();

	return Optional.of(range);
	}

	@AutoValue
	public abstract static class CommitMessageRange {

	public abstract int subjectStart();

	public abstract int subjectEnd();

	public abstract int changeMessageStart();

	public abstract int changeMessageEnd();

	public boolean hasChangeMessage() {
	return changeMessageStart() < changeMessageEnd();
	}

	public static Builder builder() {
	return new AutoValue_ChangeNoteUtil_CommitMessageRange.Builder();
	}

	@AutoValue.Builder
	public abstract static class Builder {

	abstract Builder subjectStart(int subjectStart);

	abstract Builder subjectEnd(int subjectEnd);

	abstract Builder changeMessageStart(int changeMessageStart);

	abstract Builder changeMessageEnd(int changeMessageEnd);

	abstract CommitMessageRange build();
	}
	}

	/** Helper class for JSON serialization. Timestamp is taken from the commit. */
	public static class AttentionStatusInNoteDb {

	final String personIdent;
	final AttentionSetUpdate.Operation operation;
	final String reason;

	AttentionStatusInNoteDb(
	String personIndent, AttentionSetUpdate.Operation operation, String reason) {
	this.personIdent = personIndent;
	this.operation = operation;
	this.reason = reason;
	}
	}

	/** The returned {@link Optional} holds the parsed entity or is empty if parsing failed. */
	static Optional<AttentionSetUpdate> attentionStatusFromJson(
	Instant timestamp, String attentionString) {
	AttentionStatusInNoteDb inNoteDb =
	gson.fromJson(attentionString, AttentionStatusInNoteDb.class);
	PersonIdent personIdent = RawParseUtils.parsePersonIdent(inNoteDb.personIdent);
	if (personIdent == null) {
	return Optional.empty();
	}
	Optional<Account.Id> account = NoteDbUtil.parseIdent(personIdent);
	return account.map(
	id ->
	AttentionSetUpdate.createFromRead(timestamp, id, inNoteDb.operation, inNoteDb.reason));
	}

	String attentionSetUpdateToJson(AttentionSetUpdate attentionSetUpdate) {
	StringBuilder stringBuilder = new StringBuilder();
	appendAccountIdIdentString(stringBuilder, attentionSetUpdate.account());
	return gson.toJson(
	new AttentionStatusInNoteDb(
	stringBuilder.toString(), attentionSetUpdate.operation(), attentionSetUpdate.reason()));
	}

	/**
	* {@link com.google.gerrit.entities.PatchSetApproval}, parsed from {@link #FOOTER_LABEL} or
	* {@link #FOOTER_COPIED_LABEL}.
	*
	* <p>In comparison to {@link com.google.gerrit.entities.PatchSetApproval}, this entity represent
	* the raw fields, parsed from the NoteDB footer line, without any interpretation of the parsed
	* values. See {@link #parseApproval} and {@link #parseCopiedApproval} for the valid {@link
	* #footerLine} values.
	*/
	@AutoValue
	public abstract static class ParsedPatchSetApproval {

	/** The original footer value, that this entity was parsed from. */
	public abstract String footerLine();

	public abstract boolean isRemoval();

	/** Either <LABEL>=VOTE or <LABEL> for {@link #isRemoval}. */
	public abstract String labelVote();

	public abstract Optional<String> uuid();

	public abstract Optional<String> accountIdent();

	public abstract Optional<String> realAccountIdent();

	public abstract Optional<String> tag();

	public static Builder builder() {
	return new AutoValue_ChangeNoteUtil_ParsedPatchSetApproval.Builder();
	}

	@AutoValue.Builder
	public abstract static class Builder {

	abstract Builder footerLine(String labelLine);

	abstract Builder isRemoval(boolean isRemoval);

	abstract Builder labelVote(String labelVote);

	abstract Builder uuid(Optional<String> uuid);

	abstract Builder accountIdent(Optional<String> accountIdent);

	abstract Builder realAccountIdent(Optional<String> realAccountIdent);

	abstract Builder tag(Optional<String> tag);

	abstract ParsedPatchSetApproval build();
	}
	}

	/**
	* Delegates parsing of {@link ParsedPatchSetApproval} from {@link #FOOTER_LABEL} line to
	* dedicated methods: {@link #parseAddedApproval} and {@link #parseRemovedApproval}
	* correspondingly.
	*/
	public static ParsedPatchSetApproval parseApproval(String footerLine)
	throws ConfigInvalidException {
	try {
	return footerLine.startsWith("-")
	? parseRemovedApproval(footerLine)
	: parseAddedApproval(footerLine);
	} catch (StringIndexOutOfBoundsException ex) {
	throw parseException(FOOTER_LABEL, footerLine, ex);
	}
	}

	/**
	* Parses added {@link ParsedPatchSetApproval} from {@link #FOOTER_LABEL} line.
	*
	* <p>Valid added approval footer examples:
	*
	* <ul>
	* <li>Label: <LABEL>=VOTE
	* <li>Label: <LABEL>=VOTE <Gerrit Account>
	* <li>Label: <LABEL>=VOTE, <UUID>
	* <li>Label: <LABEL>=VOTE, <UUID> <Gerrit Account>
	* </ul>
	*
	* <p><UUID> is optional, since the approval might have been granted before {@link
	* com.google.gerrit.entities.PatchSetApproval.UUID} was introduced.
	*
	* <p><Gerrit Account> is only persisted in cases, when the account, that granted the vote does
	* not match the account, that issued {@link ChangeUpdate} (created this NoteDB commit).
	*/
	private static ParsedPatchSetApproval parseAddedApproval(String footerLine)
	throws ConfigInvalidException {
	ParsedPatchSetApproval.Builder rawPatchSetApproval =
	ParsedPatchSetApproval.builder().footerLine(footerLine);
	rawPatchSetApproval.isRemoval(false);
	// We need some additional logic to differentiate between labels that have a UUID and those that
	// have a user with a comma. This allows us to separate the following cases (note that the
	// leading `Label: ` has been elided at this point):
	// Label: <LABEL>=VOTE, <UUID> <Gerrit Account>
	// Label: <LABEL>=VOTE <Gerrit, Account>
	int reviewerStartOffset = 0;
	int scoreStart = footerLine.indexOf('=') + 1;
	StringBuilder labelNameScore = new StringBuilder(footerLine.substring(0, scoreStart));
	for (int i = scoreStart; i < footerLine.length(); i++) {
	char currentChar = footerLine.charAt(i);

	// If we hit ',' before ' ' we have a UUID
	if (currentChar == ',') {
	labelNameScore.append(footerLine, scoreStart, i);
	int uuidStart = i + LABEL_VOTE_UUID_SEPARATOR.length();
	int uuidEnd = footerLine.indexOf(' ', uuidStart);
	String uuid = footerLine.substring(uuidStart, uuidEnd > 0 ? uuidEnd : footerLine.length());
	checkFooter(!Strings.isNullOrEmpty(uuid), FOOTER_LABEL, footerLine);
	rawPatchSetApproval.uuid(Optional.of(uuid));
	reviewerStartOffset = uuidStart + uuid.length();
	break;
	}

	// Otherwise we don't
	if (currentChar == ' ') {
	labelNameScore.append(footerLine, scoreStart, i);
	break;
	}

	// If we hit neither we're defensive assign the whole line
	if (i == footerLine.length() - 1) {
	labelNameScore = new StringBuilder(footerLine);
	break;
	}
	}

	rawPatchSetApproval.labelVote(labelNameScore.toString());

	int reviewerStart = footerLine.indexOf(' ', reviewerStartOffset);
	if (reviewerStart > 0) {
	String ident = footerLine.substring(reviewerStart + 1);
	rawPatchSetApproval.accountIdent(Optional.of(ident));
	}
	return rawPatchSetApproval.build();
	}

	/**
	* Parses removed {@link ParsedPatchSetApproval} from {@link #FOOTER_LABEL} line.
	*
	* <p>Valid removed approval footer examples:
	*
	* <ul>
	* <li>-<LABEL>
	* <li>-<LABEL> <Gerrit Account>
	* </ul>
	*
	* <p><Gerrit Account> is only persisted in cases, when the account, that granted the vote
	* does not match the account, that issued {@link ChangeUpdate} (created this NoteDB commit).
	*/
	private static ParsedPatchSetApproval parseRemovedApproval(String footerLine) {
	ParsedPatchSetApproval.Builder rawPatchSetApproval =
	ParsedPatchSetApproval.builder().footerLine(footerLine);
	rawPatchSetApproval.isRemoval(true);
	int labelStart = 1;
	int reviewerStart = footerLine.indexOf(' ', labelStart);

	rawPatchSetApproval.labelVote(
	reviewerStart != -1
	? footerLine.substring(labelStart, reviewerStart)
	: footerLine.substring(labelStart));

	if (reviewerStart > 0) {
	String ident = footerLine.substring(reviewerStart + 1);
	rawPatchSetApproval.accountIdent(Optional.of(ident));
	}
	return rawPatchSetApproval.build();
	}

	/**
	* Parses copied {@link ParsedPatchSetApproval} from {@link #FOOTER_COPIED_LABEL} line.
	*
	* <p>Footer example: Copied-Label: <LABEL>=VOTE, <UUID> <Gerrit Account>,<Gerrit Real Account>
	* :"<TAG>"
	*
	* <ul>
	* <li>":<"TAG>"" is optional.
	* <li><Gerrit Real Account> is also optional, if it was not set.
	* <li><UUID> is optional, since the approval might have been granted before {@link
	* com.google.gerrit.entities.PatchSetApproval.UUID} was introduced.
	* <li>The label, vote, and the Gerrit account are mandatory (unlike FOOTER_LABEL where Gerrit
	* Account is also optional since by default it's the committer).
	* </ul>
	*/
	public static ParsedPatchSetApproval parseCopiedApproval(String labelLine)
	throws ConfigInvalidException {
	try {
	// Copied approvals can't be explicitly removed. They are removed the same way as non-copied
	// approvals.
	checkFooter(!labelLine.startsWith("-"), FOOTER_COPIED_LABEL, labelLine);
	ParsedPatchSetApproval.Builder rawPatchSetApproval =
	ParsedPatchSetApproval.builder().footerLine(labelLine).isRemoval(false);

	int tagStart = labelLine.indexOf(":\"");
	int uuidStart = parseCopiedApprovalUuidStart(labelLine, tagStart);

	// Weird tag that contains uuid delimiter. The uuid is actually not present.
	if (tagStart != -1 && uuidStart > tagStart) {
	uuidStart = -1;
	}

	int identitiesStart =
	labelLine.indexOf(
	' ', uuidStart != -1 ? uuidStart + LABEL_VOTE_UUID_SEPARATOR.length() : 0);
	checkFooter(
	identitiesStart != -1 && identitiesStart < labelLine.length(),
	FOOTER_COPIED_LABEL,
	labelLine);

	String labelVoteStr = labelLine.substring(0, uuidStart != -1 ? uuidStart : identitiesStart);
	rawPatchSetApproval.labelVote(labelVoteStr);
	if (uuidStart != -1) {
	String uuid = labelLine.substring(uuidStart + 2, identitiesStart);
	checkFooter(!Strings.isNullOrEmpty(uuid), FOOTER_COPIED_LABEL, labelLine);
	rawPatchSetApproval.uuid(Optional.of(uuid));
	}
	// The first account is the accountId, and second (if applicable) is the realAccountId.
	List<String> identities =
	parseIdentities(
	labelLine.substring(
	identitiesStart + 1, tagStart == -1 ? labelLine.length() : tagStart));
	checkFooter(identities.size() >= 1, FOOTER_COPIED_LABEL, labelLine);

	rawPatchSetApproval.accountIdent(Optional.of(identities.get(0)));

	if (identities.size() > 1) {
	rawPatchSetApproval.realAccountIdent(Optional.of(identities.get(1)));
	}

	if (tagStart != -1) {
	// tagStart+2 skips ":\"" to parse the actual tag. Tags are in brackets.
	// line.length()-1 skips the last ".
	String tag = labelLine.substring(tagStart + 2, labelLine.length() - 1);
	rawPatchSetApproval.tag(Optional.of(tag));
	}
	return rawPatchSetApproval.build();
	} catch (StringIndexOutOfBoundsException ex) {
	throw parseException(FOOTER_COPIED_LABEL, labelLine, ex);
	}
	}

	// Return the UUID start index or -1 if no UUID is present
	private static int parseCopiedApprovalUuidStart(String line, int tagStart) {
	int separatorIndex = line.indexOf(LABEL_VOTE_UUID_SEPARATOR);

	// The first part of the condition checks whether the footer has the following format:
	// Copied-Label: <LABEL>=VOTE <Gerrit Account>,<Gerrit Real Account> :"<TAG>"
	// Weird tag that contains uuid delimiter. The uuid is actually not present.
	if ((tagStart != -1 && separatorIndex > tagStart)
	\|\|

	// The second part of the condition allows us to distinguish the following two lines:
	// Label2=+1, 577fb248e474018276351785930358ec0450e9f7 Gerrit User 1 <1@gerrit>
	// Label2=+1 User Name (company_name, department) <2@gerrit>
	(line.indexOf(' ') < separatorIndex)) {
	return -1;
	}
	return separatorIndex;
	}

	// Splitting on "," breaks for identities containing commas. The below re-implements splitting on
	// "(?<=>),", but it's 3-5x faster, as performance matters here.
	private static List<String> parseIdentities(String line) {
	List<String> idents = Splitter.on(',').splitToList(line);
	List<String> identitiesList = new ArrayList<>();
	for (int i = 0; i < idents.size(); i++) {
	if (i == 0 \|\| idents.get(i - 1).endsWith(">")) {
	identitiesList.add(idents.get(i));
	} else {
	int lastIndex = identitiesList.size() - 1;
	identitiesList.set(lastIndex, identitiesList.get(lastIndex) + "," + idents.get(i));
	}
	}
	return identitiesList;
	}

	private static void checkFooter(boolean expr, FooterKey footer, String actual)
	throws ConfigInvalidException {
	if (!expr) {
	throw parseException(footer, actual, /cause=/ null);
	}
	}

	private static ConfigInvalidException parseException(
	FooterKey footer, String actual, Throwable cause) {
	return new ConfigInvalidException(
	String.format("invalid %s: %s", footer.getName(), actual), cause);
	}
	}