Squashed 'third_party/flatbuffers/' content from commit acc9990ab
Change-Id: I48550d40d78fea996ebe74e9723a5d1f910de491
git-subtree-dir: third_party/flatbuffers
git-subtree-split: acc9990abd2206491480291b0f85f925110102ea
diff --git a/build_defs.bzl b/build_defs.bzl
new file mode 100644
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--- /dev/null
+++ b/build_defs.bzl
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+# Description:
+# BUILD rules for generating flatbuffer files in various languages.
+
+"""
+Rules for building C++ flatbuffers with Bazel.
+"""
+
+flatc_path = "@com_github_google_flatbuffers//:flatc"
+
+DEFAULT_INCLUDE_PATHS = [
+ "./",
+ "$(GENDIR)",
+ "$(BINDIR)",
+]
+
+DEFAULT_FLATC_ARGS = [
+ "--gen-object-api",
+ "--gen-compare",
+ "--no-includes",
+ "--gen-mutable",
+ "--reflect-names",
+ "--cpp-ptr-type flatbuffers::unique_ptr",
+]
+
+def flatbuffer_library_public(
+ name,
+ srcs,
+ outs,
+ language_flag,
+ out_prefix = "",
+ includes = [],
+ include_paths = DEFAULT_INCLUDE_PATHS,
+ flatc_args = DEFAULT_FLATC_ARGS,
+ reflection_name = "",
+ reflection_visibility = None,
+ output_to_bindir = False):
+ """Generates code files for reading/writing the given flatbuffers in the requested language using the public compiler.
+
+ Args:
+ name: Rule name.
+ srcs: Source .fbs files. Sent in order to the compiler.
+ outs: Output files from flatc.
+ language_flag: Target language flag. One of [-c, -j, -js].
+ out_prefix: Prepend this path to the front of all generated files except on
+ single source targets. Usually is a directory name.
+ includes: Optional, list of filegroups of schemas that the srcs depend on.
+ include_paths: Optional, list of paths the includes files can be found in.
+ flatc_args: Optional, list of additional arguments to pass to flatc.
+ reflection_name: Optional, if set this will generate the flatbuffer
+ reflection binaries for the schemas.
+ reflection_visibility: The visibility of the generated reflection Fileset.
+ output_to_bindir: Passed to genrule for output to bin directory.
+
+
+ This rule creates a filegroup(name) with all generated source files, and
+ optionally a Fileset([reflection_name]) with all generated reflection
+ binaries.
+ """
+ include_paths_cmd = ["-I %s" % (s) for s in include_paths]
+
+ # '$(@D)' when given a single source target will give the appropriate
+ # directory. Appending 'out_prefix' is only necessary when given a build
+ # target with multiple sources.
+ output_directory = (
+ ("-o $(@D)/%s" % (out_prefix)) if len(srcs) > 1 else ("-o $(@D)")
+ )
+ genrule_cmd = " ".join([
+ "SRCS=($(SRCS));",
+ "for f in $${SRCS[@]:0:%s}; do" % len(srcs),
+ "$(location %s)" % (flatc_path),
+ " ".join(include_paths_cmd),
+ " ".join(flatc_args),
+ language_flag,
+ output_directory,
+ "$$f;",
+ "done",
+ ])
+ native.genrule(
+ name = name,
+ srcs = srcs + includes,
+ outs = outs,
+ output_to_bindir = output_to_bindir,
+ tools = [flatc_path],
+ cmd = genrule_cmd,
+ message = "Generating flatbuffer files for %s:" % (name),
+ )
+ if reflection_name:
+ reflection_genrule_cmd = " ".join([
+ "SRCS=($(SRCS));",
+ "for f in $${SRCS[@]:0:%s}; do" % len(srcs),
+ "$(location %s)" % (flatc_path),
+ "-b --schema",
+ " ".join(flatc_args),
+ " ".join(include_paths_cmd),
+ language_flag,
+ output_directory,
+ "$$f;",
+ "done",
+ ])
+ reflection_outs = [
+ (out_prefix + "%s.bfbs") % (s.replace(".fbs", "").split("/")[-1])
+ for s in srcs
+ ]
+ native.genrule(
+ name = "%s_srcs" % reflection_name,
+ srcs = srcs + includes,
+ outs = reflection_outs,
+ output_to_bindir = output_to_bindir,
+ tools = [flatc_path],
+ cmd = reflection_genrule_cmd,
+ message = "Generating flatbuffer reflection binary for %s:" % (name),
+ )
+ native.Fileset(
+ name = reflection_name,
+ out = "%s_out" % reflection_name,
+ entries = [
+ native.FilesetEntry(files = reflection_outs),
+ ],
+ visibility = reflection_visibility,
+ )
+
+def flatbuffer_cc_library(
+ name,
+ srcs,
+ srcs_filegroup_name = "",
+ out_prefix = "",
+ includes = [],
+ include_paths = DEFAULT_INCLUDE_PATHS,
+ flatc_args = DEFAULT_FLATC_ARGS,
+ visibility = None,
+ srcs_filegroup_visibility = None,
+ gen_reflections = False):
+ '''A cc_library with the generated reader/writers for the given flatbuffer definitions.
+
+ Args:
+ name: Rule name.
+ srcs: Source .fbs files. Sent in order to the compiler.
+ srcs_filegroup_name: Name of the output filegroup that holds srcs. Pass this
+ filegroup into the `includes` parameter of any other
+ flatbuffer_cc_library that depends on this one's schemas.
+ out_prefix: Prepend this path to the front of all generated files. Usually
+ is a directory name.
+ includes: Optional, list of filegroups of schemas that the srcs depend on.
+ ** SEE REMARKS BELOW **
+ include_paths: Optional, list of paths the includes files can be found in.
+ flatc_args: Optional list of additional arguments to pass to flatc
+ (e.g. --gen-mutable).
+ visibility: The visibility of the generated cc_library. By default, use the
+ default visibility of the project.
+ srcs_filegroup_visibility: The visibility of the generated srcs filegroup.
+ By default, use the value of the visibility parameter above.
+ gen_reflections: Optional, if true this will generate the flatbuffer
+ reflection binaries for the schemas.
+
+ This produces:
+ filegroup([name]_srcs): all generated .h files.
+ filegroup(srcs_filegroup_name if specified, or [name]_includes if not):
+ Other flatbuffer_cc_library's can pass this in for their `includes`
+ parameter, if they depend on the schemas in this library.
+ Fileset([name]_reflection): (Optional) all generated reflection binaries.
+ cc_library([name]): library with sources and flatbuffers deps.
+
+ Remarks:
+ ** Because the genrule used to call flatc does not have any trivial way of
+ computing the output list of files transitively generated by includes and
+ --gen-includes (the default) being defined for flatc, the --gen-includes
+ flag will not work as expected. The way around this is to add a dependency
+ to the flatbuffer_cc_library defined alongside the flatc included Fileset.
+ For example you might define:
+
+ flatbuffer_cc_library(
+ name = "my_fbs",
+ srcs = [ "schemas/foo.fbs" ],
+ includes = [ "//third_party/bazz:bazz_fbs_includes" ],
+ )
+
+ In which foo.fbs includes a few files from the Fileset defined at
+ //third_party/bazz:bazz_fbs_includes. When compiling the library that
+ includes foo_generated.h, and therefore has my_fbs as a dependency, it
+ will fail to find any of the bazz *_generated.h files unless you also
+ add bazz's flatbuffer_cc_library to your own dependency list, e.g.:
+
+ cc_library(
+ name = "my_lib",
+ deps = [
+ ":my_fbs",
+ "//third_party/bazz:bazz_fbs"
+ ],
+ )
+
+ Happy dependent Flatbuffering!
+ '''
+ output_headers = [
+ (out_prefix + "%s_generated.h") % (s.replace(".fbs", "").split("/")[-1])
+ for s in srcs
+ ]
+ reflection_name = "%s_reflection" % name if gen_reflections else ""
+
+ srcs_lib = "%s_srcs" % (name)
+ flatbuffer_library_public(
+ name = srcs_lib,
+ srcs = srcs,
+ outs = output_headers,
+ language_flag = "-c",
+ out_prefix = out_prefix,
+ includes = includes,
+ include_paths = include_paths,
+ flatc_args = flatc_args,
+ reflection_name = reflection_name,
+ reflection_visibility = visibility,
+ )
+ native.cc_library(
+ name = name,
+ hdrs = [
+ ":" + srcs_lib,
+ ],
+ srcs = [
+ ":" + srcs_lib,
+ ],
+ features = [
+ "-parse_headers",
+ ],
+ deps = [
+ "@com_github_google_flatbuffers//:runtime_cc",
+ ],
+ includes = [],
+ linkstatic = 1,
+ visibility = visibility,
+ )
+
+ # A filegroup for the `srcs`. That is, all the schema files for this
+ # Flatbuffer set.
+ native.filegroup(
+ name = srcs_filegroup_name if srcs_filegroup_name else "%s_includes" % (name),
+ srcs = srcs,
+ visibility = srcs_filegroup_visibility if srcs_filegroup_visibility != None else visibility,
+ )