Reclassify heapsnapshot and nsJSInspector as not part of devtools

This resolves Issue #316

1 files changed, 143 insertions, 0 deletions

diff --git a/dom/heapsnapshot/CoreDump.proto b/dom/heapsnapshot/CoreDump.proto
new file mode 100644
index 000000000..24a223e11
--- /dev/null
+++ b/dom/heapsnapshot/CoreDump.proto
@@ -0,0 +1,143 @@
+/* -*- Mode: protobuf; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// # Core Dumps
+//
+// A core dump is a serialized snapshot of the heap graph. We serialize the heap
+// as a series of protobuf messages with each message prefixed by its Varint32
+// byte size so we can delimit individual protobuf messages (protobuf parsers
+// cannot determine where a message ends on their own).
+//
+// The first protobuf message is an instance of the `Metadata` message. All
+// subsequent messages will be instances of the `Node` message. The first of
+// these `Node` messages is the root node of the serialized heap graph. Here is
+// a diagram of our core dump format:
+//
+//     +-----------------------------------------------------------------------+
+//     | Varint32: The size of following `Metadata` message.                   |
+//     +-----------------------------------------------------------------------+
+//     | message: The core dump `Metadata` message.                            |
+//     +-----------------------------------------------------------------------+
+//     | Varint32: The size of the following `Node` message.                   |
+//     +-----------------------------------------------------------------------+
+//     | message: The first `Node` message. This is the root node.             |
+//     +-----------------------------------------------------------------------+
+//     | Varint32: The size of the following `Node` message.                   |
+//     +-----------------------------------------------------------------------+
+//     | message: A `Node` message.                                            |
+//     +-----------------------------------------------------------------------+
+//     | Varint32: The size of the following `Node` message.                   |
+//     +-----------------------------------------------------------------------+
+//     | message: A `Node` message.                                            |
+//     +-----------------------------------------------------------------------+
+//     | .                                                                     |
+//     | .                                                                     |
+//     | .                                                                     |
+//     +-----------------------------------------------------------------------+
+//
+// Core dumps should always be written with a
+// `google::protobuf::io::GzipOutputStream` and read from a
+// `google::protobuf::io::GzipInputStream`.
+//
+// Note that all strings are de-duplicated. The first time the N^th unique
+// string is encountered, the full string is serialized. Subsequent times that
+// same string is encountered, it is referenced by N. This de-duplication
+// happens across string properties, not on a per-property basis. For example,
+// if the same K^th unique string is first used as an Edge::EdgeNameOrRef and
+// then as a StackFrame::Data::FunctionDisplayNameOrRef, the first will be the
+// actual string as the functionDisplayName oneof property, and the second will
+// be a reference to the first as the edgeNameRef oneof property whose value is
+// K.
+//
+// We would ordinarily abstract these de-duplicated strings with messages of
+// their own, but unfortunately, the protobuf compiler does not have a way to
+// inline a messsage within another message and the child message must be
+// referenced by pointer. This leads to extra mallocs that we wish to avoid.
+
+
+package mozilla.devtools.protobuf;
+
+// A collection of metadata about this core dump.
+message Metadata {
+    // Number of microseconds since midnight (00:00:00) 1 January 1970 UTC.
+    optional uint64 timeStamp = 1;
+}
+
+// A serialized version of `JS::ubi::StackFrame`. Older parent frame tails are
+// de-duplicated to cut down on [de]serialization and size costs.
+message StackFrame {
+    oneof StackFrameType {
+        // This is the first time this stack frame has been serialized, and so
+        // here is all of its data.
+        Data   data = 1;
+        // A reference to a stack frame that has already been serialized and has
+        // the given number as its id.
+        uint64 ref  = 2;
+    }
+
+    message Data {
+        optional uint64        id           = 1;
+        optional StackFrame    parent       = 2;
+        optional uint32        line         = 3;
+        optional uint32        column       = 4;
+
+        // De-duplicated two-byte string.
+        oneof SourceOrRef {
+            bytes  source                   = 5;
+            uint64 sourceRef                = 6;
+        }
+
+        // De-duplicated two-byte string.
+        oneof FunctionDisplayNameOrRef {
+            bytes  functionDisplayName      = 7;
+            uint64 functionDisplayNameRef   = 8;
+        }
+
+        optional bool          isSystem     = 9;
+        optional bool          isSelfHosted = 10;
+    }
+}
+
+// A serialized version of `JS::ubi::Node` and its outgoing edges.
+message Node {
+    optional uint64     id                   = 1;
+
+    // De-duplicated two-byte string.
+    oneof TypeNameOrRef {
+        bytes           typeName             = 2;
+        uint64          typeNameRef          = 3;
+    }
+
+    optional uint64     size                 = 4;
+    repeated Edge       edges                = 5;
+    optional StackFrame allocationStack      = 6;
+
+    // De-duplicated one-byte string.
+    oneof JSObjectClassNameOrRef {
+        bytes           jsObjectClassName    = 7;
+        uint64          jsObjectClassNameRef = 8;
+    }
+
+    // JS::ubi::CoarseType. Defaults to Other.
+    optional uint32     coarseType           = 9 [default = 0];
+
+    // De-duplicated one-byte string.
+    oneof ScriptFilenameOrRef {
+        bytes           scriptFilename       = 10;
+        uint64          scriptFilenameRef    = 11;
+    }
+}
+
+// A serialized edge from the heap graph.
+message Edge {
+    optional uint64 referent    = 1;
+
+    // De-duplicated two-byte string.
+    oneof EdgeNameOrRef {
+        bytes       name    = 2;
+        uint64      nameRef = 3;
+    }
+}