1 files changed, 90 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/gen-scalar-data.py b/toolkit/components/telemetry/gen-scalar-data.py
new file mode 100644
index 000000000..6c17c602f
--- /dev/null
+++ b/toolkit/components/telemetry/gen-scalar-data.py
@@ -0,0 +1,90 @@
+# 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/.
+
+# Write out scalar information for C++.  The scalars are defined
+# in a file provided as a command-line argument.
+
+from __future__ import print_function
+from shared_telemetry_utils import StringTable, static_assert
+
+import parse_scalars
+import sys
+
+# The banner/text at the top of the generated file.
+banner = """/* This file is auto-generated, only for internal use in TelemetryScalar.h,
+   see gen-scalar-data.py. */
+"""
+
+file_header = """\
+#ifndef mozilla_TelemetryScalarData_h
+#define mozilla_TelemetryScalarData_h
+#include "ScalarInfo.h"
+namespace {
+"""
+
+file_footer = """\
+} // namespace
+#endif // mozilla_TelemetryScalarData_h
+"""
+
+def write_scalar_info(scalar, output, name_index, expiration_index):
+    """Writes a scalar entry to the output file.
+
+    :param scalar: a ScalarType instance describing the scalar.
+    :param output: the output stream.
+    :param name_index: the index of the scalar name in the strings table.
+    :param expiration_index: the index of the expiration version in the strings table.
+    """
+    cpp_guard = scalar.cpp_guard
+    if cpp_guard:
+        print("#if defined(%s)" % cpp_guard, file=output)
+
+    print("  {{ {}, {}, {}, {}, {} }},"\
+          .format(scalar.nsITelemetry_kind,
+                  name_index,
+                  expiration_index,
+                  scalar.dataset,
+                  "true" if scalar.keyed else "false"),
+          file=output)
+
+    if cpp_guard:
+        print("#endif", file=output)
+
+def write_scalar_tables(scalars, output):
+    """Writes the scalar and strings tables to an header file.
+
+    :param scalars: a list of ScalarType instances describing the scalars.
+    :param output: the output stream.
+    """
+    string_table = StringTable()
+
+    print("const ScalarInfo gScalars[] = {", file=output)
+    for s in scalars:
+        # We add both the scalar label and the expiration string to the strings
+        # table.
+        name_index = string_table.stringIndex(s.label)
+        exp_index = string_table.stringIndex(s.expires)
+        # Write the scalar info entry.
+        write_scalar_info(s, output, name_index, exp_index)
+    print("};", file=output)
+
+    string_table_name = "gScalarsStringTable"
+    string_table.writeDefinition(output, string_table_name)
+    static_assert(output, "sizeof(%s) <= UINT32_MAX" % string_table_name,
+                  "index overflow")
+
+def main(output, *filenames):
+    # Load the scalars first.
+    if len(filenames) > 1:
+        raise Exception('We don\'t support loading from more than one file.')
+    scalars = parse_scalars.load_scalars(filenames[0])
+
+    # Write the scalar data file.
+    print(banner, file=output)
+    print(file_header, file=output)
+    write_scalar_tables(scalars, output)
+    print(file_footer, file=output)
+
+if __name__ == '__main__':
+    main(sys.stdout, *sys.argv[1:])