Repository cache: add a put method determining the key itself

Add a new put method to the repository cache, that computes the cache key
itself. The key is returned, so it can be reused without having to recompute
it. This is a convenient interface for caching a file that was downloaded
without prior knowledge of its hash.

Change-Id: I6ac844f4166bf64498b87e483896d155df35475e
PiperOrigin-RevId: 193889444

2 files changed, 31 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCache.java b/src/main/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCache.java
index bd743b3532..651c0a4760 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCache.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCache.java
@@ -164,6 +164,20 @@ public class RepositoryCache {
     FileSystemUtils.copyFile(sourcePath, cacheValue);
   }
 
+  /**
+   * Copies a value from a specified path into the cache, computing the cache key itself.
+   *
+   * @param sourcePath The path of the value to be cached.
+   * @param keyType The type of key to be used.
+   * @throws IOException
+   * @return The key for the cached entry.
+   */
+  public synchronized String put(Path sourcePath, KeyType keyType) throws IOException {
+    String cacheKey = getChecksum(keyType, sourcePath);
+    put(cacheKey, sourcePath, keyType);
+    return cacheKey;
+  }
+
   private void ensureCacheDirectoryExists(KeyType keyType) throws IOException {
     Path directoryPath = keyType.getCachePath(contentAddressablePath);
     if (!directoryPath.exists()) {
@@ -236,4 +250,4 @@ public class RepositoryCache {
     return contentAddressablePath;
   }
 
-}
\ No newline at end of file
+}
diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCacheTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCacheTest.java
index dc1a690c86..35ce53c4fa 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCacheTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/cache/RepositoryCacheTest.java
@@ -84,6 +84,22 @@ public class RepositoryCacheTest {
   }
 
   /**
+   * Test that the put mehtod without cache key correctly stores the downloaded file into the cache.
+   */
+  @Test
+  public void testPutCacheValueWithoutHash() throws IOException {
+    String cacheKey = repositoryCache.put(downloadedFile, KeyType.SHA256);
+    assertThat(cacheKey).isEqualTo(downloadedFileSha256);
+
+    Path cacheEntry =
+        KeyType.SHA256.getCachePath(contentAddressableCachePath).getChild(downloadedFileSha256);
+    Path cacheValue = cacheEntry.getChild(RepositoryCache.DEFAULT_CACHE_FILENAME);
+
+    assertThat(FileSystemUtils.readContent(downloadedFile, Charset.defaultCharset()))
+        .isEqualTo(FileSystemUtils.readContent(cacheValue, Charset.defaultCharset()));
+  }
+
+  /**
    * Test that the put method is idempotent, i.e. two successive put calls
    * should not affect the final state in the cache.
    */