From 2fe6d7bc5773b6888d0db80eca75e392b3549814 Mon Sep 17 00:00:00 2001
From: Qartar <qartar@live.com>
Date: Sun, 7 Jun 2015 14:22:51 -0700
Subject: Workaround for MSVC's string literal compiler limit.

Escape characters don't count for string literal size, no need to pre-generate escape string.

Added unit test to touch enormous cpp generated descriptor.

Updated makefile to include enormous_descriptor.proto

Fixed language compatibility error.
---
 src/Makefile.am                                  |  6 ++-
 src/google/protobuf/compiler/cpp/cpp_file.cc     | 58 ++++++++++++++++++------
 src/google/protobuf/compiler/cpp/cpp_unittest.cc | 12 +++++
 3 files changed, 61 insertions(+), 15 deletions(-)

(limited to 'src')

diff --git a/src/Makefile.am b/src/Makefile.am
index 33894dc1..b8946bac 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -412,6 +412,7 @@ protoc_inputs =                                                \
   google/protobuf/unittest_drop_unknown_fields.proto           \
   google/protobuf/unittest_embed_optimize_for.proto            \
   google/protobuf/unittest_empty.proto                         \
+  google/protobuf/unittest_enormous_descriptor.proto           \
   google/protobuf/unittest_import_lite.proto                   \
   google/protobuf/unittest_import.proto                        \
   google/protobuf/unittest_import_public_lite.proto            \
@@ -453,8 +454,7 @@ EXTRA_DIST =                                                   \
   google/protobuf/compiler/ruby/ruby_generated_code.proto      \
   google/protobuf/compiler/ruby/ruby_generated_code.rb         \
   google/protobuf/compiler/package_info.h                      \
-  google/protobuf/compiler/zip_output_unittest.sh              \
-  google/protobuf/unittest_enormous_descriptor.proto
+  google/protobuf/compiler/zip_output_unittest.sh
 
 protoc_lite_outputs =                                          \
   google/protobuf/map_lite_unittest.pb.cc                      \
@@ -486,6 +486,8 @@ protoc_outputs =                                               \
   google/protobuf/unittest_embed_optimize_for.pb.h             \
   google/protobuf/unittest_empty.pb.cc                         \
   google/protobuf/unittest_empty.pb.h                          \
+  google/protobuf/unittest_enormous_descriptor.pb.cc           \
+  google/protobuf/unittest_enormous_descriptor.pb.h            \
   google/protobuf/unittest_import.pb.cc                        \
   google/protobuf/unittest_import.pb.h                         \
   google/protobuf/unittest_import_public.pb.cc                 \
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.cc b/src/google/protobuf/compiler/cpp/cpp_file.cc
index b997a51a..1f0a8205 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_file.cc
@@ -434,20 +434,52 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     string file_data;
     file_proto.SerializeToString(&file_data);
 
-    printer->Print(
-      "::google::protobuf::DescriptorPool::InternalAddGeneratedFile(");
-
-    // Only write 40 bytes per line.
-    static const int kBytesPerLine = 40;
-    for (int i = 0; i < file_data.size(); i += kBytesPerLine) {
-      printer->Print("\n  \"$data$\"",
-                     "data",
-                     EscapeTrigraphs(
-                         CEscape(file_data.substr(i, kBytesPerLine))));
+    // Workaround for MSVC: "Error C1091: compiler limit: string exceeds 65535
+    // bytes in length". Declare a static array of characters rather than use a
+    // string literal.
+    if (file_data.size() > 65535) {
+      printer->Print(
+        "static const char descriptor[] = {\n");
+      printer->Indent();
+
+      // Only write 25 bytes per line.
+      static const int kBytesPerLine = 25;
+      for (int i = 0; i < file_data.size();) {
+          for (int j = 0; j < kBytesPerLine && i < file_data.size(); ++i, ++j) {
+            printer->Print(
+              "$char$, ",
+              "char", SimpleItoa(file_data[i]));
+          }
+          printer->Print(
+            "\n");
+      }
+
+      printer->Outdent();
+      printer->Print(
+        "};\n");
+
+      printer->Print(
+        "::google::protobuf::DescriptorPool::InternalAddGeneratedFile(descriptor, $size$);\n",
+        "size", SimpleItoa(file_data.size()));
+
+    } else {
+
+      printer->Print(
+        "::google::protobuf::DescriptorPool::InternalAddGeneratedFile(");
+  
+      // Only write 40 bytes per line.
+      static const int kBytesPerLine = 40;
+      for (int i = 0; i < file_data.size(); i += kBytesPerLine) {
+        printer->Print("\n  \"$data$\"",
+                       "data",
+                       EscapeTrigraphs(
+                           CEscape(file_data.substr(i, kBytesPerLine))));
+      }
+      printer->Print(
+          ", $size$);\n",
+        "size", SimpleItoa(file_data.size()));
+  
     }
-    printer->Print(
-        ", $size$);\n",
-      "size", SimpleItoa(file_data.size()));
 
     // Call MessageFactory::InternalRegisterGeneratedFile().
     printer->Print(
diff --git a/src/google/protobuf/compiler/cpp/cpp_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_unittest.cc
index b11fb21a..bd1c0fde 100644
--- a/src/google/protobuf/compiler/cpp/cpp_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_unittest.cc
@@ -55,6 +55,7 @@
 #include <google/protobuf/unittest.pb.h>
 #include <google/protobuf/unittest_optimize_for.pb.h>
 #include <google/protobuf/unittest_embed_optimize_for.pb.h>
+#include <google/protobuf/unittest_enormous_descriptor.pb.h>
 #include <google/protobuf/unittest_no_generic_services.pb.h>
 #include <google/protobuf/test_util.h>
 #include <google/protobuf/compiler/cpp/cpp_helpers.h>
@@ -130,6 +131,17 @@ TEST(GeneratedDescriptorTest, IdenticalDescriptors) {
             generated_decsriptor_proto.DebugString());
 }
 
+// Test that generated code has proper descriptors:
+// Touch a descriptor generated from an enormous message to validate special
+// handling for descriptors exceeding the C++ standard's recommended minimum
+// limit for string literal size
+TEST(GeneratedDescriptorTest, EnormousDescriptor) {
+  const Descriptor* generated_descriptor =
+    TestEnormousDescriptor::descriptor();
+
+  EXPECT_TRUE(generated_descriptor != NULL);
+}
+
 #endif  // !PROTOBUF_TEST_NO_DESCRIPTORS
 
 // ===================================================================
-- 
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