Initial Hello World for rust compilation by bazel

Summary:
Prepping for the implementation of the rust indexer,
this commit sets up bazel builds for rust. Currently it only
builds a hello world program but the project is split into
two different components a library and an executable.

Test Plan:
Run bazel build //kythe/rust/indexer:release. If rust is
present it will build, and //kythe/rust/indexer:test will run the
tests. If rust is not present both will fail and display an error
message.

Reviewers: zarko, schroederc

Reviewed By: schroederc

Projects: #rust

Differential Revision: https://phabricator-dot-kythe-repo.appspot.com/D931

Author: djrenren

kythe/rust/indexer/.gitignore

@@ -0,0 +1,2 @@
+/target/
+/Cargo.lock

kythe/rust/indexer/BUILD

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+package(default_visibility = ["//kythe:default_visibility"])
+
+load("//tools/build_rules/rust:cargo.bzl", "cargo_lib", "cargo_bin", "cargo_test")
+
+cargo_lib(
+    name = "libindexer",
+    loc = "kythe/rust/indexer/",
+)
+
+cargo_bin(
+    name = "indexer",
+    loc = "kythe/rust/indexer/",
+)
+
+cargo_test(
+    name = "test_it_works",
+    size = "small",
+    test_name = "tests::it_works",
+    loc = "kythe/rust/indexer/",
+)

kythe/rust/indexer/Cargo.toml

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+# Copyright 2016 Google Inc. All rights reserved.
+# 
+# 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.
+
+[package]
+name = "indexer"
+version = "0.1.0"
+authors = ["John Renner <[email protected]>"]
+
+[dependencies]

kythe/rust/indexer/src/bin/indexer.rs

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+/*
+ * Copyright 2016 Google Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+extern crate indexer;
+
+fn main() {
+    indexer::say_hello();
+}

kythe/rust/indexer/src/lib.rs

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+/*
+ * Copyright 2016 Google Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+pub fn say_hello() {
+    println!("Hello World!");
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+    }
+}

tools/build_rules/rust/BUILD

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+package(
+    default_visibility = ["//visibility:public"],
+)
+
+exports_files([
+    "cargo.bzl",
+    "run_cargo.sh",
+])

tools/build_rules/rust/cargo.bzl

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+def _cargo_cmd(loc, cmd, outs=[]):
+     return "\n".join([
+             "$(location //tools/build_rules/rust:run_cargo.sh) " + loc + " \"" + cmd + "\"",
+        ] + [
+            "mv " + loc + out + " $(location " + out + ") " for out in outs 
+        ])
+
+_automatic_srcs = [
+    "Cargo.toml",
+    "src/**/*.rs",
+]
+
+def cargo_bin(name, loc, srcs=[], bin_name=None, release=False):
+    bin_name = name if bin_name == None else bin_name
+    output_path = "target/" + ("release/" if release else "debug/") + bin_name
+    native.genrule(
+        name = name,
+        srcs = srcs + native.glob(_automatic_srcs),
+        outs = [output_path],
+        cmd = _cargo_cmd(
+          loc = loc,
+          cmd = "build --bin " + (" --release" if release else "") + bin_name,
+          outs = [output_path],
+        ),
+        local = 1,
+        tools = ["//tools/build_rules/rust:run_cargo.sh"],
+        tags = ["manual", "requires-network"],
+    )
+
+def cargo_lib(name, loc, srcs=[], libname=None, release=False):
+    libname = (name if libname == None else libname) + ".rlib"
+    output_path = "target/" + ("release/" if release else "debug/") + libname
+    native.genrule(
+        name = name,
+        srcs = srcs + native.glob(_automatic_srcs),
+
+        outs = [output_path],
+        cmd = _cargo_cmd(
+          loc = loc,
+          cmd = "build --lib" + (" --release" if release else ""),
+          outs = [output_path],
+        ),
+        local = 1,
+        tools = ["//tools/build_rules/rust:run_cargo.sh"],
+        tags = ["manual", "requires-network"],
+    )
+
+# BEWARE: cargo will report a test as passing if there is no matching
+#         test name
+def cargo_test(name, size, loc, test_name, srcs=[], cargo_opts=""):
+    native.sh_test(
+        name=name,
+        size=size,
+        srcs=["//tools/build_rules/rust:run_cargo.sh"],
+        data=srcs + native.glob(_automatic_srcs),
+        args=[loc, "\"test " + cargo_opts + " " + test_name + "\""],
+        tags=["local"],
+    )

tools/build_rules/rust/run_cargo.sh

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+#!/bin/bash -e
+
+loc=$1
+cargo_args=$2
+if which cargo >/dev/null; then
+   cd $loc
+   cargo $cargo_args
+else
+   echo >&2 '\nERROR: No Rust Installation Found\n'
+   exit 1
+fi
+