Create protoc-gen-cppstream tool to auto-generate cpp proto field Ids.

It is very similiar to protoc-gen-javastream, which generates field Ids used
by ProtoOutputStream.cpp to dump protobuf data.

Bug: 65641021
Test: compile the streaming_proto:
      $ mmm -j frameworks/base/tools/streaming_proto/
      and run:
      $ PATH=$PATH:out/host/linux-x86/bin/protoc-gen-cppstream aprotoc
      --cppstream_out=tmp/
      frameworks/base/core/proto/android/service/procstats.proto
      frameworks/base/core/proto/android/util/common.proto

Change-Id: I68becc80b5166455455c5df28cd698601b4a1c1d
diff --git a/tools/streaming_proto/java/main.cpp b/tools/streaming_proto/java/main.cpp
new file mode 100644
index 0000000..b7d594b
--- /dev/null
+++ b/tools/streaming_proto/java/main.cpp
@@ -0,0 +1,474 @@
+#include "Errors.h"
+
+#include "string_utils.h"
+
+#include "google/protobuf/compiler/plugin.pb.h"
+#include "google/protobuf/io/zero_copy_stream_impl.h"
+#include "google/protobuf/text_format.h"
+
+#include <stdio.h>
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+#include <map>
+
+using namespace android::stream_proto;
+using namespace google::protobuf;
+using namespace google::protobuf::compiler;
+using namespace google::protobuf::io;
+using namespace std;
+
+const int FIELD_TYPE_SHIFT = 32;
+const uint64_t FIELD_TYPE_DOUBLE = 1L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_FLOAT = 2L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_INT32 = 3L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_INT64 = 4L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_UINT32 = 5L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_UINT64 = 6L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_SINT32 = 7L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_SINT64 = 8L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_FIXED32 = 9L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_FIXED64 = 10L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_SFIXED32 = 11L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_SFIXED64 = 12L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_BOOL = 13L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_STRING = 14L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_BYTES = 15L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_ENUM = 16L << FIELD_TYPE_SHIFT;
+const uint64_t FIELD_TYPE_OBJECT = 17L << FIELD_TYPE_SHIFT;
+
+const int FIELD_COUNT_SHIFT = 40;
+const uint64_t FIELD_COUNT_SINGLE = 1L << FIELD_COUNT_SHIFT;
+const uint64_t FIELD_COUNT_REPEATED = 2L << FIELD_COUNT_SHIFT;
+const uint64_t FIELD_COUNT_PACKED = 5L << FIELD_COUNT_SHIFT;
+
+
+/**
+ * See if this is the file for this request, and not one of the imported ones.
+ */
+static bool
+should_generate_for_file(const CodeGeneratorRequest& request, const string& file)
+{
+    const int N = request.file_to_generate_size();
+    for (int i=0; i<N; i++) {
+        if (request.file_to_generate(i) == file) {
+            return true;
+        }
+    }
+    return false;
+}
+
+/**
+ * If the descriptor gives us a class name, use that. Otherwise make one up from
+ * the filename of the .proto file.
+ */
+static string
+make_outer_class_name(const FileDescriptorProto& file_descriptor)
+{
+    string name = file_descriptor.options().java_outer_classname();
+    if (name.size() == 0) {
+        name = to_camel_case(file_base_name(file_descriptor.name()));
+        if (name.size() == 0) {
+            ERRORS.Add(UNKNOWN_FILE, UNKNOWN_LINE,
+                    "Unable to make an outer class name for file: %s",
+                    file_descriptor.name().c_str());
+            name = "Unknown";
+        }
+    }
+    return name;
+}
+
+/**
+ * Figure out the package name that we are generating.
+ */
+static string
+make_java_package(const FileDescriptorProto& file_descriptor) {
+    if (file_descriptor.options().has_java_package()) {
+        return file_descriptor.options().java_package();
+    } else {
+        return file_descriptor.package();
+    }
+}
+
+/**
+ * Figure out the name of the file we are generating.
+ */
+static string
+make_file_name(const FileDescriptorProto& file_descriptor, const string& class_name)
+{
+    string const package = make_java_package(file_descriptor);
+    string result;
+    if (package.size() > 0) {
+        result = replace_string(package, '.', '/');
+        result += '/';
+    }
+
+    result += class_name;
+    result += ".java";
+
+    return result;
+}
+
+static string
+indent_more(const string& indent)
+{
+    return indent + "    ";
+}
+
+/**
+ * Write the constants for an enum.
+ */
+static void
+write_enum(stringstream& text, const EnumDescriptorProto& enu, const string& indent)
+{
+    const int N = enu.value_size();
+    text << indent << "// enum " << enu.name() << endl;
+    for (int i=0; i<N; i++) {
+        const EnumValueDescriptorProto& value = enu.value(i);
+        text << indent << "public static final int "
+                << make_constant_name(value.name())
+                << " = " << value.number() << ";" << endl;
+    }
+    text << endl;
+}
+
+/**
+ * Get the string name for a field.
+ */
+static string
+get_proto_type(const FieldDescriptorProto& field)
+{
+    switch (field.type()) {
+        case FieldDescriptorProto::TYPE_DOUBLE:
+            return "double";
+        case FieldDescriptorProto::TYPE_FLOAT:
+            return "float";
+        case FieldDescriptorProto::TYPE_INT64:
+            return "int64";
+        case FieldDescriptorProto::TYPE_UINT64:
+            return "uint64";
+        case FieldDescriptorProto::TYPE_INT32:
+            return "int32";
+        case FieldDescriptorProto::TYPE_FIXED64:
+            return "fixed64";
+        case FieldDescriptorProto::TYPE_FIXED32:
+            return "fixed32";
+        case FieldDescriptorProto::TYPE_BOOL:
+            return "bool";
+        case FieldDescriptorProto::TYPE_STRING:
+            return "string";
+        case FieldDescriptorProto::TYPE_GROUP:
+            return "group<unsupported!>";
+        case FieldDescriptorProto::TYPE_MESSAGE:
+            return field.type_name();
+        case FieldDescriptorProto::TYPE_BYTES:
+            return "bytes";
+        case FieldDescriptorProto::TYPE_UINT32:
+            return "uint32";
+        case FieldDescriptorProto::TYPE_ENUM:
+            return field.type_name();
+        case FieldDescriptorProto::TYPE_SFIXED32:
+            return "sfixed32";
+        case FieldDescriptorProto::TYPE_SFIXED64:
+            return "sfixed64";
+        case FieldDescriptorProto::TYPE_SINT32:
+            return "sint32";
+        case FieldDescriptorProto::TYPE_SINT64:
+            return "sint64";
+        default:
+            // won't happen
+            return "void";
+    }
+}
+
+static uint64_t
+get_field_id(const FieldDescriptorProto& field)
+{
+    // Number
+    uint64_t result = (uint32_t)field.number();
+
+    // Type
+    switch (field.type()) {
+        case FieldDescriptorProto::TYPE_DOUBLE:
+            result |= FIELD_TYPE_DOUBLE;
+            break;
+        case FieldDescriptorProto::TYPE_FLOAT:
+            result |= FIELD_TYPE_FLOAT;
+            break;
+        case FieldDescriptorProto::TYPE_INT64:
+            result |= FIELD_TYPE_INT64;
+            break;
+        case FieldDescriptorProto::TYPE_UINT64:
+            result |= FIELD_TYPE_UINT64;
+            break;
+        case FieldDescriptorProto::TYPE_INT32:
+            result |= FIELD_TYPE_INT32;
+            break;
+        case FieldDescriptorProto::TYPE_FIXED64:
+            result |= FIELD_TYPE_FIXED64;
+            break;
+        case FieldDescriptorProto::TYPE_FIXED32:
+            result |= FIELD_TYPE_FIXED32;
+            break;
+        case FieldDescriptorProto::TYPE_BOOL:
+            result |= FIELD_TYPE_BOOL;
+            break;
+        case FieldDescriptorProto::TYPE_STRING:
+            result |= FIELD_TYPE_STRING;
+            break;
+        case FieldDescriptorProto::TYPE_MESSAGE:
+            result |= FIELD_TYPE_OBJECT;
+            break;
+        case FieldDescriptorProto::TYPE_BYTES:
+            result |= FIELD_TYPE_BYTES;
+            break;
+        case FieldDescriptorProto::TYPE_UINT32:
+            result |= FIELD_TYPE_UINT32;
+            break;
+        case FieldDescriptorProto::TYPE_ENUM:
+            result |= FIELD_TYPE_ENUM;
+            break;
+        case FieldDescriptorProto::TYPE_SFIXED32:
+            result |= FIELD_TYPE_SFIXED32;
+            break;
+        case FieldDescriptorProto::TYPE_SFIXED64:
+            result |= FIELD_TYPE_SFIXED64;
+            break;
+        case FieldDescriptorProto::TYPE_SINT32:
+            result |= FIELD_TYPE_SINT32;
+            break;
+        case FieldDescriptorProto::TYPE_SINT64:
+            result |= FIELD_TYPE_SINT64;
+            break;
+        default:
+            ;
+    }
+
+    // Count
+    if (field.options().packed()) {
+        result |= FIELD_COUNT_PACKED;
+    } else if (field.label() == FieldDescriptorProto::LABEL_REPEATED) {
+        result |= FIELD_COUNT_REPEATED;
+    } else {
+        result |= FIELD_COUNT_SINGLE;
+    }
+
+    return result;
+}
+
+/**
+ * Write a field.
+ */
+static void
+write_field(stringstream& text, const FieldDescriptorProto& field, const string& indent)
+{
+    string optional_comment = field.label() == FieldDescriptorProto::LABEL_OPTIONAL
+            ? "optional " : "";
+    string repeated_comment = field.label() == FieldDescriptorProto::LABEL_REPEATED
+            ? "repeated " : "";
+    string proto_type = get_proto_type(field);
+    string packed_comment = field.options().packed()
+            ? " [packed=true]" : "";
+    text << indent << "// " << optional_comment << repeated_comment << proto_type << ' '
+            << field.name() << " = " << field.number() << packed_comment << ';' << endl;
+
+    text << indent << "public static final long " << make_constant_name(field.name()) << " = 0x";
+
+    ios::fmtflags fmt(text.flags());
+    text << setfill('0') << setw(16) << hex << get_field_id(field);
+    text.flags(fmt);
+
+    text << "L;" << endl;
+
+    text << endl;
+}
+
+/**
+ * Write a Message constants class.
+ */
+static void
+write_message(stringstream& text, const DescriptorProto& message, const string& indent)
+{
+    int N;
+    const string indented = indent_more(indent);
+
+    text << indent << "// message " << message.name() << endl;
+    text << indent << "public final class " << message.name() << " {" << endl;
+    text << endl;
+
+    // Enums
+    N = message.enum_type_size();
+    for (int i=0; i<N; i++) {
+        write_enum(text, message.enum_type(i), indented);
+    }
+
+    // Nested classes
+    N = message.nested_type_size();
+    for (int i=0; i<N; i++) {
+        write_message(text, message.nested_type(i), indented);
+    }
+
+    // Fields
+    N = message.field_size();
+    for (int i=0; i<N; i++) {
+        write_field(text, message.field(i), indented);
+    }
+
+    text << indent << "}" << endl;
+    text << endl;
+}
+
+/**
+ * Write the contents of a file.
+ *
+ * If there are enums and generate_outer is false, invalid java code will be generated.
+ */
+static void
+write_file(CodeGeneratorResponse* response, const FileDescriptorProto& file_descriptor,
+        const string& filename, bool generate_outer,
+        const vector<EnumDescriptorProto>& enums, const vector<DescriptorProto>& messages)
+{
+    stringstream text;
+
+    string const package_name = make_java_package(file_descriptor);
+    string const outer_class_name = make_outer_class_name(file_descriptor);
+
+    text << "// Generated by protoc-gen-javastream. DO NOT MODIFY." << endl;
+    text << "// source: " << file_descriptor.name() << endl << endl;
+
+    if (package_name.size() > 0) {
+        if (package_name.size() > 0) {
+            text << "package " << package_name << ";" << endl;
+            text << endl;
+        }
+    }
+
+    // This bit of policy is android api rules specific: Raw proto classes
+    // must never be in the API
+    text << "/** @hide */" << endl;
+//    text << "@android.annotation.TestApi" << endl;
+
+    if (generate_outer) {
+        text << "public final class " << outer_class_name << " {" << endl;
+        text << endl;
+    }
+
+    size_t N;
+    const string indented = generate_outer ? indent_more("") : string();
+    
+    N = enums.size();
+    for (size_t i=0; i<N; i++) {
+        write_enum(text, enums[i], indented);
+    }
+
+    N = messages.size();
+    for (size_t i=0; i<N; i++) {
+        write_message(text, messages[i], indented);
+    }
+
+    if (generate_outer) {
+        text << "}" << endl;
+    }
+
+    CodeGeneratorResponse::File* file_response = response->add_file();
+    file_response->set_name(filename);
+    file_response->set_content(text.str());
+}
+
+/**
+ * Write one file per class.  Put all of the enums into the "outer" class.
+ */
+static void
+write_multiple_files(CodeGeneratorResponse* response, const FileDescriptorProto& file_descriptor)
+{
+    // If there is anything to put in the outer class file, create one
+    if (file_descriptor.enum_type_size() > 0) {
+        vector<EnumDescriptorProto> enums;
+        int N = file_descriptor.enum_type_size();
+        for (int i=0; i<N; i++) {
+            enums.push_back(file_descriptor.enum_type(i));
+        }
+
+        vector<DescriptorProto> messages;
+
+        write_file(response, file_descriptor,
+                make_file_name(file_descriptor, make_outer_class_name(file_descriptor)),
+                true, enums, messages);
+    }
+
+    // For each of the message types, make a file
+    int N = file_descriptor.message_type_size();
+    for (int i=0; i<N; i++) {
+        vector<EnumDescriptorProto> enums;
+
+        vector<DescriptorProto> messages;
+        messages.push_back(file_descriptor.message_type(i));
+
+        write_file(response, file_descriptor,
+                make_file_name(file_descriptor, file_descriptor.message_type(i).name()),
+                false, enums, messages);
+    }
+}
+
+static void
+write_single_file(CodeGeneratorResponse* response, const FileDescriptorProto& file_descriptor)
+{
+    int N;
+
+    vector<EnumDescriptorProto> enums;
+    N = file_descriptor.enum_type_size();
+    for (int i=0; i<N; i++) {
+        enums.push_back(file_descriptor.enum_type(i));
+    }
+
+    vector<DescriptorProto> messages;
+    N = file_descriptor.message_type_size();
+    for (int i=0; i<N; i++) {
+        messages.push_back(file_descriptor.message_type(i));
+    }
+
+    write_file(response, file_descriptor,
+            make_file_name(file_descriptor, make_outer_class_name(file_descriptor)),
+            true, enums, messages);
+}
+
+/**
+ * Main.
+ */
+int
+main(int argc, char const*const* argv)
+{
+    (void)argc;
+    (void)argv;
+
+    GOOGLE_PROTOBUF_VERIFY_VERSION;
+
+    CodeGeneratorRequest request;
+    CodeGeneratorResponse response;
+
+    // Read the request
+    request.ParseFromIstream(&cin);
+
+    // Build the files we need.
+    const int N = request.proto_file_size();
+    for (int i=0; i<N; i++) {
+        const FileDescriptorProto& file_descriptor = request.proto_file(i);
+        if (should_generate_for_file(request, file_descriptor.name())) {
+            if (file_descriptor.options().java_multiple_files()) {
+                write_multiple_files(&response, file_descriptor);
+            } else {
+                write_single_file(&response, file_descriptor);
+            }
+        }
+    }
+
+    // If we had errors, don't write the response. Print the errors and exit.
+    if (ERRORS.HasErrors()) {
+        ERRORS.Print();
+        return 1;
+    }
+
+    // If we didn't have errors, write the response and exit happily.
+    response.SerializeToOstream(&cout);
+    return 0;
+}