DfsReaderOptions: read loadRevIndexInParallel from config

The options have the field but it isn't loaded from the config. This
forces a workaround downstream.

Read the option from the config, as the others.

Change-Id: I7720812e0577d8f45f6b7f5b8495a8b64729125e

Author: ifradeo

Documentation/config-options.md

@@ -31,6 +31,7 @@ For details on native git options see also the official [git config documentatio
 | `core.dfs.blockSize` | `64 kiB` | ⃞ | Size in bytes of a single window read in from the pack file into the DFS block cache. |
 | `core.dfs.concurrencyLevel` | `32` | ⃞ | The estimated number of threads concurrently accessing the DFS block cache. |
 | `core.dfs.deltaBaseCacheLimit` | `10 MiB` | ⃞ | Maximum number of bytes to hold in per-reader DFS delta base cache. |
+| `core.dfs.loadRevIndexInParallel` | false; | ⃞ | Try to load the reverse index in parallel with the bitmap index. |
 | `core.dfs.streamFileThreshold` | `50 MiB` | ⃞ | The size threshold beyond which objects must be streamed. |
 | `core.dfs.streamBuffer` | Block size of the pack | ⃞ | Number of bytes to use for buffering when streaming a pack file during copying. If 0 the block size of the pack is used|
 | `core.dfs.streamRatio` | `0.30` | ⃞ | Ratio of DFS block cache to occupy with a copied pack. Values between `0` and `1.0`. |

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsReaderOptions.java

@@ -13,6 +13,7 @@
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_CORE_SECTION;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_DFS_SECTION;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_DELTA_BASE_CACHE_LIMIT;
+import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_LOAD_REV_INDEX_IN_PARALLEL;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_STREAM_BUFFER;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_STREAM_FILE_THRESHOLD;
 import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_USE_OBJECT_SIZE_INDEX;
@@ -197,6 +198,9 @@ public DfsReaderOptions fromConfig(Config rc) {
 		setUseObjectSizeIndex(rc.getBoolean(CONFIG_CORE_SECTION,
 				CONFIG_DFS_SECTION, CONFIG_KEY_USE_OBJECT_SIZE_INDEX,
 				false));
+		setLoadRevIndexInParallel(
+				rc.getBoolean(CONFIG_CORE_SECTION, CONFIG_DFS_SECTION,
+						CONFIG_KEY_LOAD_REV_INDEX_IN_PARALLEL, false));
 		return this;
 	}
 }

org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java

@@ -1027,4 +1027,11 @@ public final class ConfigConstants {
 	 * @since 7.0
 	 */
 	public static final String CONFIG_KEY_USE_OBJECT_SIZE_INDEX = "useObjectSizeIndex";
+
+	/**
+	 * The "loadRevIndexInParallel" key
+	 *
+	 * @since 7.1
+	 */
+	public static final String CONFIG_KEY_LOAD_REV_INDEX_IN_PARALLEL = "loadRevIndexInParallel";
 }