Add preliminary C++ API.

This change also adds an external dependency for gmock to the Bazel
build, which is used by the C++ library's unit test.

Issue #71

Author: davidzchen

.gitignore

@@ -10,6 +10,7 @@
 jsonnet
 _jsonnet.so
 libjsonnet.so
+libjsonnet++.so
 libjsonnet.js
 libjsonnet_test_file
 libjsonnet_test_snippet

BUILD

@@ -8,7 +8,7 @@ filegroup(
 genrule(
     name = "gen-std-jsonnet-h",
     srcs = ["stdlib/std.jsonnet"],
-    outs = ["core/std.jsonnet.h"],
+    outs = ["std.jsonnet.h"],
     cmd = "((od -v -Anone -t u1 $< | tr \" \" \"\n\" | grep -v \"^$$\" " +
           "| tr \"\n\" \",\" ) && echo \"0\") > $@; " +
           "echo >> $@",
@@ -19,12 +19,13 @@ cc_library(
     srcs = [
         "core/desugarer.cpp",
         "core/formatter.cpp",
+        "core/libjsonnet.cpp",
         "core/lexer.cpp",
         "core/parser.cpp",
         "core/static_analysis.cpp",
         "core/string_utils.cpp",
         "core/vm.cpp",
-        "core/std.jsonnet.h",
+        "std.jsonnet.h",
     ],
     hdrs = [
         "core/ast.h",
@@ -38,17 +39,24 @@ cc_library(
         "core/string_utils.h",
         "core/unicode.h",
         "core/vm.h",
-        "include/libjsonnet.h",
+    ],
+    deps = [
+        "//include:libjsonnet",
     ],
     linkopts = ["-lm"],
-    includes = ["core", "include"],
+    includes = [
+        "core",
+        "include",
+    ],
 )
 
 cc_library(
     name = "libjsonnet",
     srcs = ["core/libjsonnet.cpp"],
-    hdrs = ["include/libjsonnet.h"],
-    deps = [":jsonnet-common"],
+    deps = [
+        ":jsonnet-common",
+        "//include:libjsonnet",
+    ],
     includes = ["include"],
 )
 

Makefile

@@ -50,16 +50,24 @@ LIB_SRC = \
 	core/static_analysis.cpp \
 	core/string_utils.cpp \
 	core/vm.cpp
+
 LIB_OBJ = $(LIB_SRC:.cpp=.o)
 
+LIB_CPP_SRC = \
+	cpp/libjsonnet++.cc
+
+LIB_CPP_OBJ = $(LIB_OBJ) $(LIB_CPP_SRC:.cc=.o)
+
 ALL = \
 	jsonnet \
 	libjsonnet.so \
+	libjsonnet++.so \
 	libjsonnet_test_snippet \
 	libjsonnet_test_file \
 	libjsonnet.js \
 	doc/js/libjsonnet.js \
 	$(LIB_OBJ)
+
 ALL_HEADERS = \
 	core/ast.h \
 	core/desugarer.h \
@@ -72,7 +80,8 @@ ALL_HEADERS = \
 	core/string_utils.h \
 	core/vm.h \
 	core/std.jsonnet.h \
-	include/libjsonnet.h
+	include/libjsonnet.h \
+	include/libjsonnet++.h
 
 default: jsonnet
 
@@ -91,7 +100,9 @@ test: jsonnet libjsonnet.so libjsonnet_test_snippet libjsonnet_test_file
 MAKEDEPEND_SRCS = \
 	cmd/jsonnet.cpp \
 	core/libjsonnet_test_snippet.c \
-	core/libjsonnet_test_file.c
+	core/libjsonnet_test_file.c \
+	cpp/libjsonnet_cpp_test_snippet.c \
+	cpp/libjsonnet_cpp_test_file.c
 
 depend:
 	makedepend -f- $(LIB_SRC) $(MAKEDEPEND_SRCS) > Makefile.depend
@@ -102,6 +113,9 @@ core/desugarer.cpp: core/std.jsonnet.h
 %.o: %.cpp
 	$(CXX) -c $(CXXFLAGS) $< -o $@
 
+%.o: %.cc
+	$(CXX) -c $(CXXFLAGS) $< -o $@
+
 # Commandline executable.
 jsonnet: cmd/jsonnet.cpp $(LIB_OBJ)
 	$(CXX) $(CXXFLAGS) $(LDFLAGS) $< $(LIB_SRC:.cpp=.o) -o $@
@@ -110,6 +124,9 @@ jsonnet: cmd/jsonnet.cpp $(LIB_OBJ)
 libjsonnet.so: $(LIB_OBJ)
 	$(CXX) $(LDFLAGS) $(LIB_OBJ) $(SHARED_LDFLAGS) -o $@
 
+libjsonnet++.so: $(LIB_CPP_OBJ)
+	$(CXX) $(LDFLAGS) $(LIB_CPP_OBJ) $(SHARED_LDFLAGS) -o $@
+
 # Javascript build of C binding
 JS_EXPORTED_FUNCTIONS = 'EXPORTED_FUNCTIONS=["_jsonnet_make", "_jsonnet_evaluate_snippet", "_jsonnet_realloc", "_jsonnet_destroy"]'
 

WORKSPACE

@@ -0,0 +1,16 @@
+new_http_archive(
+    name = "gmock_archive",
+    url = "https://googlemock.googlecode.com/files/gmock-1.7.0.zip",
+    sha256 = "26fcbb5925b74ad5fc8c26b0495dfc96353f4d553492eb97e85a8a6d2f43095b",
+    build_file = "gmock.BUILD",
+)
+
+bind(
+    name = "gtest",
+    actual = "@gmock_archive//:gtest",
+)
+
+bind(
+    name = "gtest_main",
+    actual = "@gmock_archive//:gtest_main",
+)

cpp/BUILD

@@ -0,0 +1,21 @@
+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+    name = "libjsonnet++",
+    srcs = ["libjsonnet++.cc"],
+    deps = [
+        "//:libjsonnet",
+        "//include:libjsonnet++",
+    ],
+    includes = ["include"],
+)
+
+cc_test(
+    name = "libjsonnet++_test",
+    srcs = ["libjsonnet++_test.cc"],
+    data = ["//cpp/testdata"],
+    deps = [
+        ":libjsonnet++",
+        "//external:gtest_main",
+    ],
+)

cpp/libjsonnet++.cc

@@ -0,0 +1,157 @@
+// Copyright 2015 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.
+
+#include "libjsonnet++.h"
+
+namespace jsonnet {
+
+Jsonnet::Jsonnet() {}
+Jsonnet::~Jsonnet() {
+  if (vm_ != nullptr) {
+    ::jsonnet_destroy(vm_);
+  }
+}
+
+/* static */
+std::string Jsonnet::Version() {
+  return ::jsonnet_version();
+}
+
+bool Jsonnet::Init() {
+  vm_ = static_cast<struct JsonnetVm*>(::jsonnet_make());
+  return vm_ != nullptr;
+}
+
+void Jsonnet::SetMaxStack(uint32_t depth) {
+  ::jsonnet_max_stack(vm_, static_cast<unsigned>(depth));
+}
+
+void Jsonnet::SetGcMinObjects(uint32_t objects) {
+  ::jsonnet_gc_min_objects(vm_, static_cast<unsigned>(objects));
+}
+
+void Jsonnet::SetGcGrowthTrigger(double growth) {
+  ::jsonnet_gc_growth_trigger(vm_, growth);
+}
+
+void Jsonnet::SetStringOutput(bool string_output) {
+  ::jsonnet_string_output(vm_, string_output);
+}
+
+void Jsonnet::AddImportPath(const std::string& path) {
+  ::jsonnet_jpath_add(vm_, path.c_str());
+}
+
+void Jsonnet::SetMaxTrace(uint32_t lines) {
+  ::jsonnet_max_trace(vm_, static_cast<unsigned>(lines));
+}
+
+void Jsonnet::BindExtVar(const std::string& key, const std::string& value) {
+  ::jsonnet_ext_var(vm_, key.c_str(), value.c_str());
+}
+
+void Jsonnet::BindExtCodeVar(const std::string& key,
+                             const std::string& value) {
+  ::jsonnet_ext_code(vm_, key.c_str(), value.c_str());
+}
+
+bool Jsonnet::EvaluateFile(const std::string& filename, std::string* output) {
+  if (output == nullptr) {
+    return false;
+  }
+  int error = 0;
+  const char* jsonnet_output =
+      ::jsonnet_evaluate_file(vm_, filename.c_str(), &error);
+  if (error != 0) {
+    last_error_.assign(jsonnet_output);
+    return false;
+  }
+  output->assign(jsonnet_output);
+  return true;
+}
+
+bool Jsonnet::EvaluateSnippet(const std::string& filename,
+                              const std::string& snippet,
+                              std::string* output) {
+  if (output == nullptr) {
+    return false;
+  }
+  int error = 0;
+  const char* jsonnet_output = ::jsonnet_evaluate_snippet(
+      vm_, filename.c_str(), snippet.c_str(), &error);
+  if (error != 0) {
+    last_error_.assign(jsonnet_output);
+    return false;
+  }
+  output->assign(jsonnet_output);
+  return true;
+}
+
+namespace {
+void ParseMultiOutput(const char* jsonnet_output,
+                      std::map<std::string, std::string>* outputs) {
+  for (const char* c = jsonnet_output; *c != '\0'; ) {
+    const char *filename = c;
+    const char *c2 = c;
+    while (*c2 != '\0') ++c2;
+    ++c2;
+    const char *json = c2;
+    while (*c2 != '\0') ++c2;
+    ++c2;
+    c = c2;
+    outputs->insert(std::make_pair(filename, json));
+  }
+}
+}  // namespace
+
+bool Jsonnet::EvaluateFileMulti(
+    const std::string& filename,
+    std::map<std::string, std::string>* outputs) {
+  if (outputs == nullptr) {
+    return false;
+  }
+  int error = 0;
+  const char* jsonnet_output =
+      ::jsonnet_evaluate_file_multi(vm_, filename.c_str(), &error);
+  if (error != 0) {
+    last_error_.assign(jsonnet_output);
+    return false;
+  }
+  ParseMultiOutput(jsonnet_output, outputs);
+  return true;
+}
+
+bool Jsonnet::EvaluateSnippetMulti(
+    const std::string& filename,
+    const std::string& snippet,
+    std::map<std::string, std::string>* outputs) {
+  if (outputs == nullptr) {
+    return false;
+  }
+  int error = 0;
+  const char* jsonnet_output = ::jsonnet_evaluate_snippet_multi(
+      vm_, filename.c_str(), snippet.c_str(), &error);
+  if (error != 0) {
+    last_error_.assign(jsonnet_output);
+    return false;
+  }
+  ParseMultiOutput(jsonnet_output, outputs);
+  return true;
+}
+
+std::string Jsonnet::LastError() const {
+  return last_error_;
+}
+
+}  // namespace jsonnet