Support ${shardeduserid} in ref patterns

This makes it possible to assign for each user permissions for the own
user branch, e.g. in the All-Users project READ for Registered-Users
can be granted on refs/users/${shardeduserid}.

Change-Id: If7d0ba58743562a0706edfc7ef602c8add2249d5
Signed-off-by: Edwin Kempin <ekempin@google.com>

Documentation/access-control.txt

@@ -220,11 +220,16 @@ shortest possible pattern expansion must be a valid ref name:
 thus `^refs/heads/.*/name` will fail because `refs/heads//name`
 is not a valid reference, but `^refs/heads/.+/name` will work.
 
-References can have the current user name automatically included,
+References can have the user name or the sharded account ID of the
-creating dynamic access controls that change to match the currently
+current user automatically included, creating dynamic access controls
-logged in user.  For example to provide a personal sandbox space
+that change to match the currently logged in user.  For example to
-to all developers, `+refs/heads/sandbox/${username}/*+` allowing
+provide a personal sandbox space to all developers,
-the user 'joe' to use 'refs/heads/sandbox/joe/foo'.
+`+refs/heads/sandbox/${username}/*+` allows the user 'joe' to use
+'refs/heads/sandbox/joe/foo'. The sharded account ID can be used to
+give users access to their user branch in the `All-Users` repository,
+for example `+refs/users/${shardeduserid}+` is resolved to
+'refs/users/23/1011123' if the account ID of the current user is
+`1011123`.
 
 When evaluating a reference-level access right, Gerrit will use
 the full set of access rights to determine if the user

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/accounts/AccountIT.java

@@ -61,6 +61,7 @@ import com.google.gerrit.reviewdb.client.AccountExternalId;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.ProjectConfig;
+import com.google.gerrit.server.project.RefPattern;
 import com.google.gerrit.server.util.MagicBranch;
 import com.google.gerrit.testutil.ConfigSuite;
 import com.google.gerrit.testutil.FakeEmailSender.Message;
@@ -393,7 +394,8 @@ public class AccountIT extends AbstractDaemonTest {
     }
 
     // allow each user to read its own user branch
-    grant(Permission.READ, allUsers, RefNames.REFS_USERS + "*", false,
+    grant(Permission.READ, allUsers,
+        RefNames.REFS_USERS + "${" + RefPattern.USERID_SHARDED + "}", false,
         REGISTERED_USERS);
 
     // fetch user branch using refs/users/YY/XXXXXXX

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/RefNames.java

@@ -84,14 +84,7 @@ public class RefNames {
   public static String changeMetaRef(Change.Id id) {
     StringBuilder r = new StringBuilder();
     r.append(REFS_CHANGES);
-    int n = id.get();
+    r.append(shard(id.get()));
-    int m = n % 100;
-    if (m < 10) {
-      r.append('0');
-    }
-    r.append(m);
-    r.append('/');
-    r.append(n);
     r.append(META_SUFFIX);
     return r.toString();
   }
@@ -99,14 +92,7 @@ public class RefNames {
   public static String refsUsers(Account.Id accountId) {
     StringBuilder r = new StringBuilder();
     r.append(REFS_USERS);
-    int account = accountId.get();
+    r.append(shard(accountId.get()));
-    int m = account % 100;
-    if (m < 10) {
-      r.append('0');
-    }
-    r.append(m);
-    r.append('/');
-    r.append(account);
     return r.toString();
   }
 
@@ -135,6 +121,16 @@ public class RefNames {
   private static StringBuilder buildRefsPrefix(String prefix, int id) {
     StringBuilder r = new StringBuilder();
     r.append(prefix);
+    r.append(shard(id));
+    r.append('/');
+    return r;
+  }
+
+  public static String shard(int id) {
+    if (id < 0) {
+      return null;
+    }
+    StringBuilder r = new StringBuilder();
     int n = id % 100;
     if (n < 10) {
       r.append('0');
@@ -142,8 +138,7 @@ public class RefNames {
     r.append(n);
     r.append('/');
     r.append(id);
-    r.append('/');
+    return r.toString();
-    return r;
   }
 
   /**

gerrit-reviewdb/src/test/java/com/google/gerrit/reviewdb/client/RefNamesTest.java

@@ -141,4 +141,14 @@ public class RefNamesTest {
     assertThat(parseRefSuffix("a4")).isNull();
     assertThat(parseRefSuffix("4a")).isNull();
   }
+
+  @Test
+  public void shard() throws Exception {
+    assertThat(RefNames.shard(1011123)).isEqualTo("23/1011123");
+    assertThat(RefNames.shard(537)).isEqualTo("37/537");
+    assertThat(RefNames.shard(12)).isEqualTo("12/12");
+    assertThat(RefNames.shard(0)).isEqualTo("00/0");
+    assertThat(RefNames.shard(1)).isEqualTo("01/1");
+    assertThat(RefNames.shard(-1)).isNull();
+  }
 }

gerrit-server/src/main/java/com/google/gerrit/server/project/RefPattern.java

@@ -26,6 +26,7 @@ import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 
 public class RefPattern {
+  public static final String USERID_SHARDED = "shardeduserid";
   public static final String USERNAME = "username";
 
   public static String shortestExample(String refPattern) {
@@ -77,7 +78,9 @@ public class RefPattern {
   public static void validateRegExp(String refPattern)
       throws InvalidNameException {
     try {
-      Pattern.compile(refPattern.replace("${" + USERNAME + "}/", ""));
+      refPattern = refPattern.replace("${" + USERID_SHARDED + "}", "");
+      refPattern = refPattern.replace("${" + USERNAME + "}", "");
+      Pattern.compile(refPattern);
     } catch (PatternSyntaxException e) {
       throw new InvalidNameException(refPattern + " " + e.getMessage());
     }

gerrit-server/src/main/java/com/google/gerrit/server/project/RefPatternMatcher.java

@@ -16,14 +16,18 @@ package com.google.gerrit.server.project;
 
 import static com.google.gerrit.server.project.RefPattern.isRE;
 
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.gerrit.common.data.ParameterizedString;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.server.CurrentUser;
 
 import dk.brics.automaton.Automaton;
 
-import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 import java.util.Set;
 import java.util.regex.Pattern;
 
@@ -89,15 +93,17 @@ public abstract class RefPatternMatcher {
       template = new ParameterizedString(pattern);
 
       if (isRE(pattern)) {
-        // Replace ${username} with ":USERNAME:" as : is not legal
+        // Replace ${username} and ${shardeduserid} with ":PLACEHOLDER:"
-        // in a reference and the string :USERNAME: is not likely to
+        // as : is not legal in a reference and the string :PLACEHOLDER:
-        // be a valid part of the regex. This later allows the pattern
+        // is not likely to be a valid part of the regex. This later
-        // prefix to be clipped, saving time on evaluation.
+        // allows the pattern prefix to be clipped, saving time on
-        String replacement = ":" + RefPattern.USERNAME.toUpperCase() + ":";
+        // evaluation.
+        String replacement = ":PLACEHOLDER:";
+        Map<String, String> params = ImmutableMap.of(
+            RefPattern.USERID_SHARDED, replacement,
+            RefPattern.USERNAME, replacement);
         Automaton am =
-            RefPattern.toRegExp(
+            RefPattern.toRegExp(template.replace(params)).toAutomaton();
-                template.replace(Collections.singletonMap(RefPattern.USERNAME,
-                    replacement))).toAutomaton();
         String rePrefix = am.getCommonPrefix();
         prefix = rePrefix.substring(0, rePrefix.indexOf(replacement));
       } else {
@@ -119,8 +125,11 @@ public abstract class RefPatternMatcher {
           u = username;
         }
 
-        RefPatternMatcher next = getMatcher(expand(template, u));
+        Account.Id accountId = user.isIdentifiedUser()
-        if (next != null && next.match(expand(ref, u), user)) {
+            ? user.getAccountId()
+            : null;
+        RefPatternMatcher next = getMatcher(expand(template, u, accountId));
+        if (next != null && next.match(expand(ref, u, accountId), user)) {
           return true;
         }
       }
@@ -147,16 +156,21 @@ public abstract class RefPatternMatcher {
       return ref.startsWith(prefix);
     }
 
-    private String expand(String parameterizedRef, String userName) {
+    private String expand(String parameterizedRef, String userName, Account.Id accountId) {
       if (parameterizedRef.contains("${")) {
-        return expand(new ParameterizedString(parameterizedRef), userName);
+        return expand(new ParameterizedString(parameterizedRef), userName, accountId);
       }
       return parameterizedRef;
     }
 
-    private String expand(ParameterizedString parameterizedRef, String userName) {
+    private String expand(ParameterizedString parameterizedRef, String userName,
-      return parameterizedRef
+        Account.Id accountId) {
-          .replace(Collections.singletonMap(RefPattern.USERNAME, userName));
+      Map<String, String> params = new HashMap<>();
+      params.put(RefPattern.USERNAME, userName);
+      if (accountId != null) {
+        params.put(RefPattern.USERID_SHARDED, RefNames.shard(accountId.get()));
+      }
+      return parameterizedRef.replace(params);
     }
   }
 }