Bug 1215955 - Add deleteSnapshot to HeapAnalysisWorker. r=fitzgen

devtools/shared/heapsnapshot/HeapAnalysesClient.js

@@ -51,6 +51,17 @@ HeapAnalysesClient.prototype.readHeapSnapshot = function (snapshotFilePath) {
   return this._worker.performTask("readHeapSnapshot", { snapshotFilePath });
 };
 
+/**
+ * Tell the worker to delete all references to the snapshot and dominator trees
+ * linked to the provided snapshot file path.
+ *
+ * @param {String} snapshotFilePath
+ * @return Promise<undefined>
+ */
+HeapAnalysesClient.prototype.deleteHeapSnapshot = function (snapshotFilePath) {
+  return this._worker.performTask("deleteHeapSnapshot", { snapshotFilePath });
+};
+
 /**
  * Request the creation time given a snapshot file path. Returns `null`
  * if snapshot does not exist.

devtools/shared/heapsnapshot/HeapAnalysesWorker.js

@@ -32,6 +32,24 @@ workerHelper.createTask(self, "readHeapSnapshot", ({ snapshotFilePath }) => {
   return true;
 });
 
+/**
+ * @see HeapAnalysesClient.prototype.deleteHeapSnapshot
+ */
+workerHelper.createTask(self, "deleteHeapSnapshot", ({ snapshotFilePath }) => {
+  let snapshot = snapshots[snapshotFilePath];
+  if (!snapshot) {
+    throw new Error(`No known heap snapshot for '${snapshotFilePath}'`);
+  }
+
+  snapshots[snapshotFilePath] = undefined;
+
+  let dominatorTreeId = dominatorTreeSnapshots.indexOf(snapshot);
+  if (dominatorTreeId != -1) {
+    dominatorTreeSnapshots[dominatorTreeId] = undefined;
+    dominatorTrees[dominatorTreeId] = undefined;
+  }
+});
+
 /**
  * @see HeapAnalysesClient.prototype.takeCensus
  */

devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_01.js

@@ -0,0 +1,59 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that the HeapAnalyses{Client,Worker} can delete heap snapshots.
+
+function run_test() {
+  run_next_test();
+}
+
+const breakdown = {
+  by: "coarseType",
+  objects: { by: "count", count: true, bytes: true },
+  scripts: { by: "count", count: true, bytes: true },
+  strings: { by: "count", count: true, bytes: true },
+  other: { by: "count", count: true, bytes: true },
+};
+
+add_task(function* () {
+  const client = new HeapAnalysesClient();
+
+  const snapshotFilePath = saveNewHeapSnapshot();
+  yield client.readHeapSnapshot(snapshotFilePath);
+  ok(true, "Should have read the heap snapshot");
+
+  let dominatorTreeId = yield client.computeDominatorTree(snapshotFilePath);
+  ok(true, "Should have computed the dominator tree");
+
+  yield client.deleteHeapSnapshot(snapshotFilePath);
+  ok(true, "Should have deleted the snapshot");
+
+  let threw = false;
+  try {
+    yield client.getDominatorTree({
+      dominatorTreeId: dominatorTreeId,
+      breakdown
+    });
+  } catch (_) {
+    threw = true;
+  }
+  ok(threw, "getDominatorTree on deleted tree should throw an error");
+
+  threw = false;
+  try {
+    yield client.computeDominatorTree(snapshotFilePath);
+  } catch (_) {
+    threw = true;
+  }
+  ok(threw, "computeDominatorTree on deleted snapshot should throw an error");
+
+  threw = false;
+  try {
+    yield client.takeCensus(snapshotFilePath);
+  } catch (_) {
+    threw = true;
+  }
+  ok(threw, "takeCensus on deleted tree should throw an error");
+
+  client.destroy();
+});

devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_02.js

@@ -0,0 +1,22 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test deleteHeapSnapshot is a noop if the provided path matches no snapshot
+
+function run_test() {
+  run_next_test();
+}
+
+add_task(function* () {
+  const client = new HeapAnalysesClient();
+
+  let threw = false;
+  try {
+    yield client.deleteHeapSnapshot("path-does-not-exist");
+  } catch (_) {
+    threw = true;
+  }
+  ok(threw, "deleteHeapSnapshot on non-existant path should throw an error");
+
+  client.destroy();
+});

devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_deleteHeapSnapshot_03.js

@@ -0,0 +1,62 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test other dominatorTrees can still be retrieved after deleting a snapshot
+
+function run_test() {
+  run_next_test();
+}
+
+const breakdown = {
+  by: "coarseType",
+  objects: { by: "count", count: true, bytes: true },
+  scripts: { by: "count", count: true, bytes: true },
+  strings: { by: "count", count: true, bytes: true },
+  other: { by: "count", count: true, bytes: true },
+};
+
+function* createSnapshotAndDominatorTree(client) {
+  let snapshotFilePath = saveNewHeapSnapshot();
+  yield client.readHeapSnapshot(snapshotFilePath);
+  let dominatorTreeId = yield client.computeDominatorTree(snapshotFilePath);
+  return { dominatorTreeId, snapshotFilePath };
+}
+
+add_task(function* () {
+  const client = new HeapAnalysesClient();
+
+  let savedSnapshots = [
+    yield createSnapshotAndDominatorTree(client),
+    yield createSnapshotAndDominatorTree(client),
+    yield createSnapshotAndDominatorTree(client)
+  ];
+  ok(true, "Create 3 snapshots and dominator trees");
+
+  yield client.deleteHeapSnapshot(savedSnapshots[1].snapshotFilePath);
+  ok(true, "Snapshot deleted");
+
+  let tree = yield client.getDominatorTree({
+    dominatorTreeId: savedSnapshots[0].dominatorTreeId,
+    breakdown
+  });
+  ok(tree, "Should get a valid tree for first snapshot");
+
+  let threw = false;
+  try {
+    yield client.getDominatorTree({
+      dominatorTreeId: savedSnapshots[1].dominatorTreeId,
+      breakdown
+    });
+  } catch (_) {
+    threw = true;
+  }
+  ok(threw, "getDominatorTree on a deleted snapshot should throw an error");
+
+  tree = yield client.getDominatorTree({
+    dominatorTreeId: savedSnapshots[2].dominatorTreeId,
+    breakdown
+  });
+  ok(tree, "Should get a valid tree for third snapshot");
+
+  client.destroy();
+});

devtools/shared/heapsnapshot/tests/unit/xpcshell.ini

@@ -43,6 +43,9 @@ support-files =
 [test_DominatorTreeNode_LabelAndShallowSize_04.js]
 [test_HeapAnalyses_computeDominatorTree_01.js]
 [test_HeapAnalyses_computeDominatorTree_02.js]
+[test_HeapAnalyses_deleteHeapSnapshot_01.js]
+[test_HeapAnalyses_deleteHeapSnapshot_02.js]
+[test_HeapAnalyses_deleteHeapSnapshot_03.js]
 [test_HeapAnalyses_getCreationTime_01.js]
 [test_HeapAnalyses_getDominatorTree_01.js]
 [test_HeapAnalyses_getDominatorTree_02.js]