[Support/Compression] - Change zlib API to return Error instead of custom status.

Previously API returned custom enum values.
Patch changes it to return Error with string description.
That should help users to report errors in universal way.

Differential revision: https://reviews.llvm.org/D28684

llvm-svn: 292214

1 files changed, 47 insertions, 36 deletions

diff --git a/llvm/lib/Support/Compression.cpp b/llvm/lib/Support/Compression.cpp
index 5d556462e89..c279d10f6c6 100644
--- a/llvm/lib/Support/Compression.cpp
+++ b/llvm/lib/Support/Compression.cpp
@@ -16,6 +16,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
 #include <zlib.h>
@@ -24,6 +25,10 @@
 using namespace llvm;
 
 #if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+static Error createError(StringRef Err) {
+  return make_error<StringError>(Err, inconvertibleErrorCode());
+}
+
 static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
   switch (Level) {
     case zlib::NoCompression: return 0;
@@ -34,53 +39,59 @@ static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
   llvm_unreachable("Invalid zlib::CompressionLevel!");
 }
 
-static zlib::Status encodeZlibReturnValue(int ReturnValue) {
-  switch (ReturnValue) {
-    case Z_OK: return zlib::StatusOK;
-    case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
-    case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
-    case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
-    case Z_DATA_ERROR: return zlib::StatusInvalidData;
-    default: llvm_unreachable("unknown zlib return status!");
+static StringRef convertZlibCodeToString(int Code) {
+  switch (Code) {
+  case Z_MEM_ERROR:
+    return "zlib error: Z_MEM_ERROR";
+  case Z_BUF_ERROR:
+    return "zlib error: Z_BUF_ERROR";
+  case Z_STREAM_ERROR:
+    return "zlib error: Z_STREAM_ERROR";
+  case Z_DATA_ERROR:
+    return "zlib error: Z_DATA_ERROR";
+  case Z_OK:
+  default:
+    llvm_unreachable("unknown or unexpected zlib status code");
   }
 }
 
 bool zlib::isAvailable() { return true; }
-zlib::Status zlib::compress(StringRef InputBuffer,
-                            SmallVectorImpl<char> &CompressedBuffer,
-                            CompressionLevel Level) {
+
+Error zlib::compress(StringRef InputBuffer,
+                     SmallVectorImpl<char> &CompressedBuffer,
+                     CompressionLevel Level) {
   unsigned long CompressedSize = ::compressBound(InputBuffer.size());
   CompressedBuffer.resize(CompressedSize);
   int CLevel = encodeZlibCompressionLevel(Level);
-  Status Res = encodeZlibReturnValue(::compress2(
-      (Bytef *)CompressedBuffer.data(), &CompressedSize,
-      (const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
+  int Res = ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
+                        (const Bytef *)InputBuffer.data(), InputBuffer.size(),
+                        CLevel);
   // Tell MemorySanitizer that zlib output buffer is fully initialized.
   // This avoids a false report when running LLVM with uninstrumented ZLib.
   __msan_unpoison(CompressedBuffer.data(), CompressedSize);
   CompressedBuffer.resize(CompressedSize);
-  return Res;
+  return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
 }
 
-zlib::Status zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
-                              size_t &UncompressedSize) {
-  Status Res = encodeZlibReturnValue(
+Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                       size_t &UncompressedSize) {
+  int Res =
       ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
-                   (const Bytef *)InputBuffer.data(), InputBuffer.size()));
+                   (const Bytef *)InputBuffer.data(), InputBuffer.size());
   // Tell MemorySanitizer that zlib output buffer is fully initialized.
   // This avoids a false report when running LLVM with uninstrumented ZLib.
   __msan_unpoison(UncompressedBuffer, UncompressedSize);
-  return Res;
+  return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
 }
 
-zlib::Status zlib::uncompress(StringRef InputBuffer,
-                              SmallVectorImpl<char> &UncompressedBuffer,
-                              size_t UncompressedSize) {
+Error zlib::uncompress(StringRef InputBuffer,
+                       SmallVectorImpl<char> &UncompressedBuffer,
+                       size_t UncompressedSize) {
   UncompressedBuffer.resize(UncompressedSize);
-  Status Res =
+  Error E =
       uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
   UncompressedBuffer.resize(UncompressedSize);
-  return Res;
+  return E;
 }
 
 uint32_t zlib::crc32(StringRef Buffer) {
@@ -89,19 +100,19 @@ uint32_t zlib::crc32(StringRef Buffer) {
 
 #else
 bool zlib::isAvailable() { return false; }
-zlib::Status zlib::compress(StringRef InputBuffer,
-                            SmallVectorImpl<char> &CompressedBuffer,
-                            CompressionLevel Level) {
-  return zlib::StatusUnsupported;
+Error zlib::compress(StringRef InputBuffer,
+                     SmallVectorImpl<char> &CompressedBuffer,
+                     CompressionLevel Level) {
+  llvm_unreachable("zlib::compress is unavailable");
 }
-zlib::Status zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
-                              size_t &UncompressedSize) {
-  return zlib::StatusUnsupported;
+Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                       size_t &UncompressedSize) {
+  llvm_unreachable("zlib::uncompress is unavailable");
 }
-zlib::Status zlib::uncompress(StringRef InputBuffer,
-                              SmallVectorImpl<char> &UncompressedBuffer,
-                              size_t UncompressedSize) {
-  return zlib::StatusUnsupported;
+Error zlib::uncompress(StringRef InputBuffer,
+                       SmallVectorImpl<char> &UncompressedBuffer,
+                       size_t UncompressedSize) {
+  llvm_unreachable("zlib::uncompress is unavailable");
 }
 uint32_t zlib::crc32(StringRef Buffer) {
   llvm_unreachable("zlib::crc32 is unavailable");