Import of the watch repository from Pebble

tools/js/dump_snapshot_literals.py

@@ -0,0 +1,101 @@
+#! /usr/bin/env python
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+import struct
+
+ROCKY_HEADER_SIZE = 8
+ROCKY_HEADER_FMT = "4sB3x"
+
+JERRY_HEADER_SIZE = 16
+JERRY_HEADER_FMT = "<4I"
+
+LIT_TABLE_HEADER_SIZE = 8
+LIT_TABLE_HEADER_FMT = "<2I"
+
+LIT_STRING_HEADER_SIZE = 2
+LIT_STRING_HEADER_FMT = "<H"
+
+
+def _get_aligned_literal_length(length):
+    LITERAL_ALIGNMENT = (1 << 2)
+    return ((length) + (LITERAL_ALIGNMENT - 1)) & ~(LITERAL_ALIGNMENT - 1)
+
+
+def main(snapshot_path):
+    with open(snapshot_path, 'rb') as fin:
+        # TODO: This should be generalized to a prefix string, not a Rocky header
+        rocky_header = struct.unpack(ROCKY_HEADER_FMT, fin.read(ROCKY_HEADER_SIZE))
+        print "Rocky Header"
+        print "  Signature: {}".format(rocky_header[0])
+        print "  Version:   0x{:02x}".format(rocky_header[1])
+        print
+
+        jerry_header = struct.unpack(JERRY_HEADER_FMT, fin.read(JERRY_HEADER_SIZE))
+        print "Jerry Header"
+        print "  Version: {}".format(jerry_header[0])
+        print "  lit_table_offset: {}".format(jerry_header[1])
+        print "  lit_table_size:   {}".format(jerry_header[2])
+        print "  is_run_global:    {}".format(jerry_header[3])
+        print
+
+        fin.seek(jerry_header[1] + ROCKY_HEADER_SIZE, 0)  # position to beginning of literal table
+
+        lit_header = struct.unpack(LIT_TABLE_HEADER_FMT, fin.read(LIT_TABLE_HEADER_SIZE))
+        lit_string_count = lit_header[0]
+        lit_number_count = lit_header[1]
+        print "Literal Header"
+        print "  String Count: {}".format(lit_string_count)
+        print "  Number Count: {}".format(lit_number_count)
+        print
+
+        # Now dump the literal tables
+        offset = 0
+        for i in xrange(lit_string_count):
+            length = struct.unpack(LIT_STRING_HEADER_FMT, fin.read(LIT_STRING_HEADER_SIZE))[0]
+            aligned_length = _get_aligned_literal_length(2 + length)
+            s = struct.unpack("{}s".format(length), fin.read(length))[0]
+            print "0x{:08x}: String: '{}'".format(offset, s)
+
+            move = aligned_length - length - 2  # - 2 since the header was already read
+            if move > 0:
+                fin.seek(move, 1)
+            offset += aligned_length
+
+        remaining_length = jerry_header[2] - offset - LIT_TABLE_HEADER_SIZE
+        number_length = remaining_length / float(lit_number_count)
+        if not number_length.is_integer():
+            print "Invalid offset for start of number literals"
+            return 1
+        number_length = int(number_length)
+
+        for i in xrange(lit_number_count):
+            length = number_length
+            aligned_length = _get_aligned_literal_length(length)
+            n = struct.unpack("d" if length == 8 else "f", fin.read(length))[0]
+            print "0x{:08x}: Number: {}".format(offset, n)
+
+            move = aligned_length - length
+            if move > 0:
+                fin.seek(move, 1)
+            offset += aligned_length
+
+        print "Numbers are {}-bit".format(number_length * 8)
+        return 0
+
+
+if __name__ == "__main__":
+    rc = main(sys.argv[1])
+    sys.exit(rc)