1 files changed, 147 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py b/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py
new file mode 100644
index 0000000000..8f224c5140
--- /dev/null
+++ b/toolkit/components/telemetry/build_scripts/gen_histogram_enum.py
@@ -0,0 +1,147 @@
+# 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 a C++ enum definition whose members are the names of
+# histograms as well as the following other members:
+#
+#   - HistogramCount
+#   - HistogramFirstUseCounter
+#   - HistogramLastUseCounter
+#   - HistogramUseCounterCount
+#
+# The histograms are defined in files provided as command-line arguments.
+
+import itertools
+import sys
+
+import buildconfig
+from mozparsers import parse_histograms
+from mozparsers.shared_telemetry_utils import ParserError
+
+banner = """/* This file is auto-generated, see gen_histogram_enum.py.  */
+"""
+
+header = """
+#ifndef mozilla_TelemetryHistogramEnums_h
+#define mozilla_TelemetryHistogramEnums_h
+
+#include <cstdint>
+#include <type_traits>
+
+namespace mozilla {
+namespace Telemetry {
+"""
+
+footer = """
+} // namespace mozilla
+} // namespace Telemetry
+#endif // mozilla_TelemetryHistogramEnums_h"""
+
+
+def get_histogram_typename(histogram):
+    name = histogram.name()
+    if name.startswith("USE_COUNTER2_"):
+        return "UseCounterWorker" if name.endswith("_WORKER") else "UseCounter"
+    return None
+
+
+def main(output, *filenames):
+    # Print header.
+    print(banner, file=output)
+    print(header, file=output)
+
+    # Load the histograms.
+    try:
+        all_histograms = list(parse_histograms.from_files(filenames))
+    except ParserError as ex:
+        print("\nError processing histograms:\n" + str(ex) + "\n")
+        sys.exit(1)
+
+    groups = itertools.groupby(all_histograms, get_histogram_typename)
+
+    # Print the histogram enums.
+    # Note that parse_histograms.py guarantees that all of the
+    # USE_COUNTER2_*_WORKER and USE_COUNTER2_* histograms are both defined in a
+    # contiguous block.
+    print("enum HistogramID : uint32_t {", file=output)
+    seen_group_types = {"UseCounter": False, "UseCounterWorker": False}
+    for (group_type, histograms) in groups:
+        if group_type is not None:
+            assert isinstance(group_type, str)
+            assert group_type in seen_group_types.keys()
+            assert not seen_group_types[group_type]
+            seen_group_types[group_type] = True
+            # The Histogram*DUMMY enum variables are used to make the computation
+            # of Histogram{First,Last}* easier.  Otherwise, we'd have to special
+            # case the first and last histogram in the group.
+            print("  HistogramFirst%s," % group_type, file=output)
+            print(
+                "  Histogram{0}DUMMY1 = HistogramFirst{0} - 1,".format(group_type),
+                file=output,
+            )
+
+        for histogram in histograms:
+            if histogram.record_on_os(buildconfig.substs["OS_TARGET"]):
+                print("  %s," % histogram.name(), file=output)
+
+        if group_type is not None:
+            assert isinstance(group_type, str)
+            print("  Histogram%sDUMMY2," % group_type, file=output)
+            print(
+                "  HistogramLast{0} = Histogram{0}DUMMY2 - 1,".format(group_type),
+                file=output,
+            )
+
+    print("  HistogramCount,", file=output)
+
+    for (key, value) in sorted(seen_group_types.items()):
+        if value:
+            print(
+                "  Histogram{0}Count = HistogramLast{0} - HistogramFirst{0} + 1,".format(
+                    key
+                ),
+                file=output,
+            )
+        else:
+            print("  HistogramFirst%s = 0," % key, file=output)
+            print("  HistogramLast%s = 0," % key, file=output)
+            print("  Histogram%sCount = 0," % key, file=output)
+
+    print("};", file=output)
+
+    # Write categorical label enums.
+    categorical = filter(lambda h: h.kind() == "categorical", all_histograms)
+    categorical = filter(
+        lambda h: h.record_on_os(buildconfig.substs["OS_TARGET"]), categorical
+    )
+    enums = [("LABELS_" + h.name(), h.labels(), h.name()) for h in categorical]
+    for name, labels, _ in enums:
+        print("\nenum class %s : uint32_t {" % name, file=output)
+        print("  %s" % ",\n  ".join(labels), file=output)
+        print("};", file=output)
+
+    print(
+        "\ntemplate<class T> struct IsCategoricalLabelEnum : std::false_type {};",
+        file=output,
+    )
+    for name, _, _ in enums:
+        print(
+            "template<> struct IsCategoricalLabelEnum<%s> : std::true_type {};" % name,
+            file=output,
+        )
+
+    print("\ntemplate<class T> struct CategoricalLabelId {};", file=output)
+    for name, _, id in enums:
+        print(
+            "template<> struct CategoricalLabelId<%s> : "
+            "std::integral_constant<uint32_t, %s> {};" % (name, id),
+            file=output,
+        )
+
+    # Footer.
+    print(footer, file=output)
+
+
+if __name__ == "__main__":
+    main(sys.stdout, *sys.argv[1:])