1 files changed, 117 insertions, 0 deletions
diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ProjectChangeId.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ProjectChangeId.java
new file mode 100644
index 0000000000..684867be2e
--- /dev/null
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ProjectChangeId.java
@@ -0,0 +1,117 @@
+// Copyright (C) 2017 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.change;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.common.PageLinks;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Project;
+import java.util.Objects;
+
+/** Provides logic for parsing a numeric change id and project from a URL. */
+public class ProjectChangeId {
+
+  /** Parses a {@link ProjectChangeId} from it's string representation. */
+  public static ProjectChangeId create(String token) {
+    String mutableToken = token;
+    // Try parsing /c/project/+/numericChangeId where token is project/+/numericChangeId
+    int delimiter = mutableToken.indexOf(PageLinks.PROJECT_CHANGE_DELIMITER);
+    Project.NameKey project = null;
+    if (delimiter > 0) {
+      project = new Project.NameKey(token.substring(0, delimiter));
+      mutableToken =
+          mutableToken.substring(delimiter + PageLinks.PROJECT_CHANGE_DELIMITER.length());
+    }
+
+    // Try parsing /c/numericChangeId where token is numericChangeId
+    int s = mutableToken.indexOf('/');
+    if (s > 0) {
+      mutableToken = mutableToken.substring(0, s);
+    }
+    // Special case: project/+/1233,edit/
+    s = mutableToken.indexOf(",edit");
+    if (s > 0) {
+      mutableToken = mutableToken.substring(0, s);
+    }
+    Integer cId = tryParse(mutableToken);
+    if (cId != null) {
+      return new ProjectChangeId(project, new Change.Id(cId));
+    }
+
+    throw new IllegalArgumentException(token + " is not a valid change identifier");
+  }
+
+  @Nullable private final Project.NameKey project;
+  private final Change.Id changeId;
+
+  @VisibleForTesting
+  ProjectChangeId(@Nullable Project.NameKey project, Change.Id changeId) {
+    this.project = project;
+    this.changeId = changeId;
+  }
+
+  @Nullable
+  public Project.NameKey getProject() {
+    return project;
+  }
+
+  public Change.Id getChangeId() {
+    return changeId;
+  }
+
+  /**
+   * Calculate the length of the string representation of the change ID that was parsed from the
+   * token.
+   *
+   * @return the length of the {@link com.google.gerrit.reviewdb.client.Change.Id} if no project was
+   *     parsed from the token. The length of {@link
+   *     com.google.gerrit.reviewdb.client.Project.NameKey} + the delimiter + the length of {@link
+   *     com.google.gerrit.reviewdb.client.Change.Id} otherwise.
+   */
+  public int identifierLength() {
+    if (project == null) {
+      return String.valueOf(changeId).length();
+    }
+    return PageLinks.toChangeId(project, changeId).length();
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (obj instanceof ProjectChangeId) {
+      ProjectChangeId other = (ProjectChangeId) obj;
+      return Objects.equals(changeId, other.changeId) && Objects.equals(project, other.project);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(changeId, project);
+  }
+
+  @Override
+  public String toString() {
+    return "ProjectChangeId.Result{changeId: " + changeId + ", project: " + project + "}";
+  }
+
+  private static Integer tryParse(String s) {
+    try {
+      return Integer.parseInt(s);
+    } catch (NumberFormatException e) {
+      return null;
+    }
+  }
+}