ListProjects: print projects list using secondary index

Render the list of projects to OutputStream leveraging the
projects secondary index instead of relying on the in-memory cache.

Change-Id: I864e1c3cd63b206c0f9dc76bbaa6de99ddfdc0d4

java/com/google/gerrit/server/restapi/project/ListProjects.java

@@ -313,7 +313,7 @@ public class ListProjects implements RestReadView<TopLevelResource> {
       throws BadRequestException, PermissionBackendException {
     if (format == OutputFormat.TEXT) {
       ByteArrayOutputStream buf = new ByteArrayOutputStream();
-      display(buf);
+      displayToStream(buf);
       return BinaryResult.create(buf.toByteArray())
           .setContentType("text/plain")
           .setCharacterEncoding(UTF_8);
@@ -340,6 +340,7 @@ public class ListProjects implements RestReadView<TopLevelResource> {
             && isNullOrEmpty(matchSubstring) // TODO: see Issue 10446
             && type == FilterType.ALL
             && showBranch.isEmpty()
+            && !showTree
         ? Optional.of(stateToQuery())
         : Optional.empty();
   }
@@ -379,7 +380,47 @@ public class ListProjects implements RestReadView<TopLevelResource> {
     return p;
   }
 
-  public SortedMap<String, ProjectInfo> display(@Nullable OutputStream displayOutputStream)
+  private void printQueryResults(String query, PrintWriter out) throws BadRequestException {
+    try {
+      if (format.isJson()) {
+        format.newGson().toJson(applyAsQuery(query), out);
+      } else {
+        newProjectsNamesStream(query).forEach(out::println);
+      }
+      out.flush();
+    } catch (OrmException | MethodNotAllowedException e) {
+      logger.atWarning().withCause(e).log(
+          "Internal error while processing the query '{}' request", query);
+      throw new BadRequestException("Internal error while processing the query request");
+    }
+  }
+
+  private Stream<String> newProjectsNamesStream(String query)
+      throws OrmException, MethodNotAllowedException, BadRequestException {
+    Stream<String> projects =
+        queryProjectsProvider.get().withQuery(query).apply().stream().map(p -> p.name).skip(start);
+    if (limit > 0) {
+      projects = projects.limit(limit);
+    }
+
+    return projects;
+  }
+
+  public void displayToStream(OutputStream displayOutputStream)
+      throws BadRequestException, PermissionBackendException {
+    PrintWriter stdout =
+        new PrintWriter(new BufferedWriter(new OutputStreamWriter(displayOutputStream, UTF_8)));
+    Optional<String> projectsQuery = expressAsProjectsQuery();
+
+    if (projectsQuery.isPresent()) {
+      printQueryResults(projectsQuery.get(), stdout);
+    } else {
+      display(stdout);
+    }
+  }
+
+  @Nullable
+  public SortedMap<String, ProjectInfo> display(@Nullable PrintWriter stdout)
       throws BadRequestException, PermissionBackendException {
     if (all && state != null) {
       throw new BadRequestException("'all' and 'state' may not be used together");
@@ -394,12 +435,6 @@ public class ListProjects implements RestReadView<TopLevelResource> {
       }
     }
 
-    PrintWriter stdout = null;
-    if (displayOutputStream != null) {
-      stdout =
-          new PrintWriter(new BufferedWriter(new OutputStreamWriter(displayOutputStream, UTF_8)));
-    }
-
     if (type == FilterType.PARENT_CANDIDATES) {
       // Historically, PARENT_CANDIDATES implied showDescription.
       showDescription = true;

java/com/google/gerrit/sshd/commands/ListProjectsCommand.java

@@ -41,6 +41,6 @@ public class ListProjectsCommand extends SshCommand {
         throw die("--tree and --description options are not compatible.");
       }
     }
-    impl.display(out);
+    impl.displayToStream(out);
   }
 }

javatests/com/google/gerrit/acceptance/rest/project/ListProjectsIT.java

@@ -126,7 +126,7 @@ public class ListProjectsIT extends AbstractDaemonTest {
     try (ByteArrayOutputStream displayOut = new ByteArrayOutputStream()) {
 
       listProjects.setStart(numInitialProjects);
-      listProjects.display(displayOut);
+      listProjects.displayToStream(displayOut);
 
       List<String> lines =
           Splitter.on("\n").omitEmptyStrings().splitToList(new String(displayOut.toByteArray()));
@@ -156,7 +156,7 @@ public class ListProjectsIT extends AbstractDaemonTest {
 
       listProjects.setStart(numInitialProjects);
       listProjects.setFormat(jsonFormat);
-      listProjects.display(displayOut);
+      listProjects.displayToStream(displayOut);
 
       String projectsJsonOutput = new String(displayOut.toByteArray());