Separate libdexfile external C ABI from the C++ header file.

Also add a test to compile it with C.

Test: m
Test: m test-art-{host,target}-gtest-dex_file_ext_c_test
Test: art/test/testrunner/run_build_test_target.py -j80 art-test
Bug: 120978655
Change-Id: I6e9944a2051bef9a2775bc2072df4e0ed81dc833

6 files changed, 198 insertions, 108 deletions

diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index a926d9a686..d95777f482 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -383,6 +383,7 @@ ART_TEST_MODULES := \
     art_hiddenapi_tests \
     art_imgdiag_tests \
     art_libartbase_tests \
+    art_libdexfile_external_tests \
     art_libdexfile_tests \
     art_libprofile_tests \
     art_oatdump_tests \
diff --git a/libdexfile/Android.bp b/libdexfile/Android.bp
index 9c48aa2c1b..bc7a20bc8a 100644
--- a/libdexfile/Android.bp
+++ b/libdexfile/Android.bp
@@ -176,6 +176,36 @@ art_cc_library {
     },
 }
 
+art_cc_test {
+    name: "art_libdexfile_tests",
+    defaults: [
+        "art_gtest_defaults",
+    ],
+    srcs: [
+        "dex/art_dex_file_loader_test.cc",
+        "dex/class_accessor_test.cc",
+        "dex/code_item_accessors_test.cc",
+        "dex/compact_dex_file_test.cc",
+        "dex/compact_offset_table_test.cc",
+        "dex/descriptors_names_test.cc",
+        "dex/test_dex_file_builder_test.cc",
+        "dex/dex_file_loader_test.cc",
+        "dex/dex_file_verifier_test.cc",
+        "dex/dex_instruction_test.cc",
+        "dex/primitive_test.cc",
+        "dex/string_reference_test.cc",
+        "dex/type_lookup_table_test.cc",
+        "dex/utf_test.cc",
+    ],
+    shared_libs: [
+        "libbacktrace",
+        "libziparchive",
+    ],
+    include_dirs: [
+        "external/zlib",
+    ],
+}
+
 cc_library_headers {
     name: "libdexfile_external_headers",
     host_supported: true,
@@ -227,6 +257,16 @@ cc_library {
     },
 }
 
+art_cc_test {
+    name: "art_libdexfile_external_tests",
+    host_supported: true,
+    test_per_src: true,  // For consistency with other ART gtests.
+    srcs: [
+        "external/dex_file_ext_c_test.c",
+    ],
+    header_libs: ["libdexfile_external_headers"],
+}
+
 // Support library with a C++ API for accessing the libdexfile API for external
 // (non-ART) users. They should link to their own instance of this (either
 // statically or through linker namespaces).
@@ -240,33 +280,3 @@ cc_library {
     shared_libs: ["libdexfile_external"],
     export_header_lib_headers: ["libdexfile_external_headers"],
 }
-
-art_cc_test {
-    name: "art_libdexfile_tests",
-    defaults: [
-        "art_gtest_defaults",
-    ],
-    srcs: [
-        "dex/art_dex_file_loader_test.cc",
-        "dex/class_accessor_test.cc",
-        "dex/code_item_accessors_test.cc",
-        "dex/compact_dex_file_test.cc",
-        "dex/compact_offset_table_test.cc",
-        "dex/descriptors_names_test.cc",
-        "dex/test_dex_file_builder_test.cc",
-        "dex/dex_file_loader_test.cc",
-        "dex/dex_file_verifier_test.cc",
-        "dex/dex_instruction_test.cc",
-        "dex/primitive_test.cc",
-        "dex/string_reference_test.cc",
-        "dex/type_lookup_table_test.cc",
-        "dex/utf_test.cc",
-    ],
-    shared_libs: [
-        "libbacktrace",
-        "libziparchive",
-    ],
-    include_dirs: [
-        "external/zlib",
-    ],
-}
diff --git a/libdexfile/external/dex_file_ext.cc b/libdexfile/external/dex_file_ext.cc
index 7bf01a8931..348ed60220 100644
--- a/libdexfile/external/dex_file_ext.cc
+++ b/libdexfile/external/dex_file_ext.cc
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "art_api/dex_file_external.h"
+
 #include <inttypes.h>
 #include <stdint.h>
 #include <sys/mman.h>
@@ -39,18 +41,9 @@
 #include <dex/dex_file-inl.h>
 #include <dex/dex_file_loader.h>
 
-#include "art_api/dex_file_support.h"
-
-extern "C" class ExtDexFileString {
- public:
-  const std::string str_;
-};
-
 namespace art {
 namespace {
 
-const ExtDexFileString empty_string{""};
-
 struct MethodCacheEntry {
   int32_t offset;  // Offset relative to the start of the dex file header.
   int32_t len;
@@ -77,9 +70,15 @@ class MappedFileContainer : public DexFileContainer {
 
 extern "C" {
 
+struct ExtDexFileString {
+  const std::string str_;
+};
+
+static const ExtDexFileString empty_string{""};
+
 const ExtDexFileString* ExtDexFileMakeString(const char* str) {
   if (str[0] == '\0') {
-    return &art::empty_string;
+    return &empty_string;
   }
   return new ExtDexFileString{str};
 }
@@ -92,14 +91,15 @@ const char* ExtDexFileGetString(const ExtDexFileString* ext_string, /*out*/ size
 
 void ExtDexFileFreeString(const ExtDexFileString* ext_string) {
   DCHECK(ext_string != nullptr);
-  if (ext_string != &art::empty_string) {
+  if (ext_string != &empty_string) {
     delete (ext_string);
   }
 }
 
 // Wraps DexFile to add the caching needed by the external interface. This is
 // what gets passed over as ExtDexFile*.
-class ExtDexFile {
+struct ExtDexFile {
+ private:
   // Method cache for GetMethodInfoForOffset. This is populated as we iterate
   // sequentially through the class defs. MethodCacheEntry.name is only set for
   // methods returned by GetMethodInfoForOffset.
diff --git a/libdexfile/external/dex_file_ext_c_test.c b/libdexfile/external/dex_file_ext_c_test.c
new file mode 100644
index 0000000000..ad0737a292
--- /dev/null
+++ b/libdexfile/external/dex_file_ext_c_test.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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 <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+/* The main purpose of this test is to ensure this C header compiles in C, so
+ * that no C++ features inadvertently leak into the C ABI. */
+#include "art_api/dex_file_external.h"
+
+static const char gtest_output_arg[] = "--gtest_output=xml:";
+static const char gtest_output_xml[] = "\
+<?xml version=\"1.0\"?>\n\
+<testsuites tests=\"0\" failures=\"0\" disabled=\"0\" errors=\"0\" name=\"AllTests\">";
+
+/* Writes a dummy gtest xml report to the given path. */
+static int write_gtest_output_xml(char* gtest_output_path) {
+  FILE* output_fd = fopen(gtest_output_path, "w");
+  if (output_fd == NULL) {
+    fprintf(stderr, "Failed to open %s: %s\n", gtest_output_path, strerror(errno));
+    return 1;
+  }
+  if (fprintf(output_fd, gtest_output_xml) != sizeof(gtest_output_xml) - 1) {
+    fprintf(stderr, "Failed to write %s: %s\n", gtest_output_path, strerror(errno));
+    return 1;
+  }
+  if (fclose(output_fd) != 0) {
+    fprintf(stderr, "Failed to close %s: %s\n", gtest_output_path, strerror(errno));
+    return 1;
+  }
+  return 0;
+}
+
+int main(int argc, char** argv) {
+  if (argc >= 1 && strncmp(argv[1], gtest_output_arg, sizeof(gtest_output_arg) - 1) == 0) {
+    /* The ART gtest framework expects all tests to understand --gtest_output. */
+    return write_gtest_output_xml(argv[1] + sizeof(gtest_output_arg) - 1);
+  }
+  return 0;
+}
diff --git a/libdexfile/external/include/art_api/dex_file_external.h b/libdexfile/external/include/art_api/dex_file_external.h
new file mode 100644
index 0000000000..b29235f9ab
--- /dev/null
+++ b/libdexfile/external/include/art_api/dex_file_external.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_DEX_FILE_EXTERNAL_H_
+#define ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_DEX_FILE_EXTERNAL_H_
+
+// Dex file external API
+
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// This is the stable C ABI that backs art_api::dex below. Structs and functions
+// may only be added here. C++ users should use dex_file_support.h instead.
+
+// Opaque wrapper for an std::string allocated in libdexfile which must be freed
+// using ExtDexFileFreeString.
+struct ExtDexFileString;
+
+// Returns an ExtDexFileString initialized to the given string.
+const struct ExtDexFileString* ExtDexFileMakeString(const char* str);
+
+// Returns a pointer to the underlying null-terminated character array and its
+// size for the given ExtDexFileString.
+const char* ExtDexFileGetString(const struct ExtDexFileString* ext_string, /*out*/ size_t* size);
+
+// Frees an ExtDexFileString.
+void ExtDexFileFreeString(const struct ExtDexFileString* ext_string);
+
+struct ExtDexFileMethodInfo {
+  int32_t offset;
+  int32_t len;
+  const struct ExtDexFileString* name;
+};
+
+struct ExtDexFile;
+
+// See art_api::dex::DexFile::OpenFromMemory. Returns true on success.
+int ExtDexFileOpenFromMemory(const void* addr,
+                             /*inout*/ size_t* size,
+                             const char* location,
+                             /*out*/ const struct ExtDexFileString** error_msg,
+                             /*out*/ struct ExtDexFile** ext_dex_file);
+
+// See art_api::dex::DexFile::OpenFromFd. Returns true on success.
+int ExtDexFileOpenFromFd(int fd,
+                         off_t offset,
+                         const char* location,
+                         /*out*/ const struct ExtDexFileString** error_msg,
+                         /*out*/ struct ExtDexFile** ext_dex_file);
+
+// See art_api::dex::DexFile::GetMethodInfoForOffset. Returns true on success.
+int ExtDexFileGetMethodInfoForOffset(struct ExtDexFile* ext_dex_file,
+                                     int64_t dex_offset,
+                                     int with_signature,
+                                     /*out*/ struct ExtDexFileMethodInfo* method_info);
+
+typedef void ExtDexFileMethodInfoCallback(const struct ExtDexFileMethodInfo* ext_method_info,
+                                          void* user_data);
+
+// See art_api::dex::DexFile::GetAllMethodInfos.
+void ExtDexFileGetAllMethodInfos(struct ExtDexFile* ext_dex_file,
+                                 int with_signature,
+                                 ExtDexFileMethodInfoCallback* method_info_cb,
+                                 void* user_data);
+
+// Frees an ExtDexFile.
+void ExtDexFileFree(struct ExtDexFile* ext_dex_file);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_DEX_FILE_EXTERNAL_H_
diff --git a/libdexfile/external/include/art_api/dex_file_support.h b/libdexfile/external/include/art_api/dex_file_support.h
index 99d60d1cd8..9a20a30c4b 100644
--- a/libdexfile/external/include/art_api/dex_file_support.h
+++ b/libdexfile/external/include/art_api/dex_file_support.h
@@ -17,9 +17,7 @@
 #ifndef ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_DEX_FILE_SUPPORT_H_
 #define ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_DEX_FILE_SUPPORT_H_
 
-// Dex file external API
-
-#include <sys/types.h>
+// C++ wrapper for the dex file external API.
 
 #include <cstring>
 #include <memory>
@@ -29,69 +27,7 @@
 
 #include <android-base/macros.h>
 
-extern "C" {
-
-// This is the stable C ABI that backs art_api::dex below. Structs and functions
-// may only be added here.
-// TODO(b/120978655): Move this to a separate pure C header.
-//
-// Clients should use the C++ wrappers in art_api::dex instead.
-
-// Opaque wrapper for an std::string allocated in libdexfile which must be freed
-// using ExtDexFileFreeString.
-class ExtDexFileString;
-
-// Returns an ExtDexFileString initialized to the given string.
-const ExtDexFileString* ExtDexFileMakeString(const char* str);
-
-// Returns a pointer to the underlying null-terminated character array and its
-// size for the given ExtDexFileString.
-const char* ExtDexFileGetString(const ExtDexFileString* ext_string, /*out*/ size_t* size);
-
-// Frees an ExtDexFileString.
-void ExtDexFileFreeString(const ExtDexFileString* ext_string);
-
-struct ExtDexFileMethodInfo {
-  int32_t offset;
-  int32_t len;
-  const ExtDexFileString* name;
-};
-
-class ExtDexFile;
-
-// See art_api::dex::DexFile::OpenFromMemory. Returns true on success.
-int ExtDexFileOpenFromMemory(const void* addr,
-                             /*inout*/ size_t* size,
-                             const char* location,
-                             /*out*/ const ExtDexFileString** error_msg,
-                             /*out*/ ExtDexFile** ext_dex_file);
-
-// See art_api::dex::DexFile::OpenFromFd. Returns true on success.
-int ExtDexFileOpenFromFd(int fd,
-                         off_t offset,
-                         const char* location,
-                         /*out*/ const ExtDexFileString** error_msg,
-                         /*out*/ ExtDexFile** ext_dex_file);
-
-// See art_api::dex::DexFile::GetMethodInfoForOffset. Returns true on success.
-int ExtDexFileGetMethodInfoForOffset(ExtDexFile* ext_dex_file,
-                                     int64_t dex_offset,
-                                     int with_signature,
-                                     /*out*/ ExtDexFileMethodInfo* method_info);
-
-typedef void ExtDexFileMethodInfoCallback(const ExtDexFileMethodInfo* ext_method_info,
-                                          void* user_data);
-
-// See art_api::dex::DexFile::GetAllMethodInfos.
-void ExtDexFileGetAllMethodInfos(ExtDexFile* ext_dex_file,
-                                 int with_signature,
-                                 ExtDexFileMethodInfoCallback* method_info_cb,
-                                 void* user_data);
-
-// Frees an ExtDexFile.
-void ExtDexFileFree(ExtDexFile* ext_dex_file);
-
-}  // extern "C"
+#include "art_api/dex_file_external.h"
 
 namespace art_api {
 namespace dex {