measure-tape

Note: As of right now, this tool is specifically designed for use by Scenic.

measure-tape is a code generator creating a function meant to measure the size of a specific target type, both in terms of bytes and handles. We call this function a “measuring tape”.

This tool is currently limited to creating measuring tapes for the HLCPP bindings only.

Build and Run

fx set core.x64 --with //tools/fidl/measure-tape:host
fx build

Then

./out/default/host_x64/measure-tape \
    --json out/default/fidling/gen/sdk/fidl/fuchsia.images/fuchsia.images.fidl.json \
    --json out/default/fidling/gen/sdk/fidl/fuchsia.ui.gfx/fuchsia.ui.gfx.fidl.json \
    --json out/default/fidling/gen/sdk/fidl/fuchsia.ui.input/fuchsia.ui.input.fidl.json \
    --json out/default/fidling/gen/sdk/fidl/fuchsia.ui.scenic/fuchsia.ui.scenic.fidl.json \
    --json out/default/fidling/gen/sdk/fidl/fuchsia.ui.views/fuchsia.ui.views.fidl.json \
    --measure fuchsia.ui.scenic/Command \
    --out-cc sdk/lib/ui/scenic/cpp/commands_sizing.cc

Testing

tl;dr See commands_sizing_test.cc.

Currently, the tool has been designed to measure fuchsia.ui.scenic/Command unions. While the tool is general purpose, and with some small tweaks will be able to be reused for other similar uses, it is currently single focused.

Testing of the tool relies on Scenic tests, and in particular

fx test scenic_cpp_unittests

To which commands_sizing_test.cc has been added.