refactor: add error_code/throwing versions of open

include/dwarfs/filesystem_v2.h

@@ -159,6 +159,10 @@ class filesystem_v2 {
 
   int open(inode_view entry) const { return impl_->open(entry); }
 
+  int open(inode_view entry, std::error_code& ec) const {
+    return impl_->open(entry, ec);
+  }
+
   size_t
   read(uint32_t inode, char* buf, size_t size, file_off_t offset = 0) const {
     return impl_->read(inode, buf, size, offset);
@@ -277,6 +281,7 @@ class filesystem_v2 {
     readlink(inode_view entry, readlink_mode mode) const = 0;
     virtual int statvfs(vfs_stat* stbuf) const = 0;
     virtual int open(inode_view entry) const = 0;
+    virtual int open(inode_view entry, std::error_code& ec) const = 0;
     virtual size_t
     read(uint32_t inode, char* buf, size_t size, file_off_t offset) const = 0;
     virtual size_t read(uint32_t inode, char* buf, size_t size,

include/dwarfs/internal/metadata_v2.h

@@ -125,7 +125,9 @@ class metadata_v2 {
     impl_->access(iv, mode, uid, gid, ec);
   }
 
-  int open(inode_view iv) const { return impl_->open(iv); }
+  int open(inode_view iv, std::error_code& ec) const {
+    return impl_->open(iv, ec);
+  }
 
   std::string
   readlink(inode_view iv, readlink_mode mode, std::error_code& ec) const {
@@ -203,7 +205,7 @@ class metadata_v2 {
     virtual void access(inode_view iv, int mode, file_stat::uid_type uid,
                         file_stat::gid_type gid, std::error_code& ec) const = 0;
 
-    virtual int open(inode_view iv) const = 0;
+    virtual int open(inode_view iv, std::error_code& ec) const = 0;
 
     virtual std::string
     readlink(inode_view iv, readlink_mode mode, std::error_code& ec) const = 0;

src/dwarfs/filesystem_v2.cpp

@@ -432,6 +432,7 @@ class filesystem_ final : public filesystem_v2::impl {
   std::string readlink(inode_view entry, readlink_mode mode) const override;
   int statvfs(vfs_stat* stbuf) const override;
   int open(inode_view entry) const override;
+  int open(inode_view entry, std::error_code& ec) const override;
   size_t read(uint32_t inode, char* buf, size_t size,
               file_off_t offset) const override;
   size_t read(uint32_t inode, char* buf, size_t size, file_off_t offset,
@@ -504,6 +505,7 @@ class filesystem_ final : public filesystem_v2::impl {
   PERFMON_CLS_TIMER_DECL(readlink_ec)
   PERFMON_CLS_TIMER_DECL(statvfs)
   PERFMON_CLS_TIMER_DECL(open)
+  PERFMON_CLS_TIMER_DECL(open_ec)
   PERFMON_CLS_TIMER_DECL(read)
   PERFMON_CLS_TIMER_DECL(read_ec)
   PERFMON_CLS_TIMER_DECL(readv_iovec)
@@ -587,6 +589,7 @@ filesystem_<LoggerPolicy>::filesystem_(
     PERFMON_CLS_TIMER_INIT(readlink_ec)
     PERFMON_CLS_TIMER_INIT(statvfs)
     PERFMON_CLS_TIMER_INIT(open)
+    PERFMON_CLS_TIMER_INIT(open_ec)
     PERFMON_CLS_TIMER_INIT(read)
     PERFMON_CLS_TIMER_INIT(read_ec)
     PERFMON_CLS_TIMER_INIT(readv_iovec)
@@ -1123,10 +1126,18 @@ int filesystem_<LoggerPolicy>::statvfs(vfs_stat* stbuf) const {
   return meta_.statvfs(stbuf);
 }
 
+template <typename LoggerPolicy>
+int filesystem_<LoggerPolicy>::open(inode_view entry,
+                                    std::error_code& ec) const {
+  PERFMON_CLS_SCOPED_SECTION(open_ec)
+  return meta_.open(entry, ec);
+}
+
 template <typename LoggerPolicy>
 int filesystem_<LoggerPolicy>::open(inode_view entry) const {
   PERFMON_CLS_SCOPED_SECTION(open)
-  return meta_.open(entry);
+  return call_ec_throw(
+      [&](std::error_code& ec) { return meta_.open(entry, ec); });
 }
 
 template <typename LoggerPolicy>

src/dwarfs/internal/metadata_v2.cpp

@@ -497,7 +497,7 @@ class metadata_ final : public metadata_v2::impl {
   void access(inode_view iv, int mode, file_stat::uid_type uid,
               file_stat::gid_type gid, std::error_code& ec) const override;
 
-  int open(inode_view iv) const override;
+  int open(inode_view iv, std::error_code& ec) const override;
 
   std::string readlink(inode_view iv, readlink_mode mode,
                        std::error_code& ec) const override;
@@ -1689,12 +1689,14 @@ void metadata_<LoggerPolicy>::access(inode_view iv, int mode,
 }
 
 template <typename LoggerPolicy>
-int metadata_<LoggerPolicy>::open(inode_view iv) const {
+int metadata_<LoggerPolicy>::open(inode_view iv, std::error_code& ec) const {
   if (iv.is_regular_file()) {
+    ec.clear();
     return iv.inode_num();
   }
 
-  return -1;
+  ec = std::make_error_code(std::errc::invalid_argument);
+  return 0;
 }
 
 template <typename LoggerPolicy>

test/dwarfs_benchmark.cpp

@@ -427,7 +427,8 @@ BENCHMARK_DEFINE_F(filesystem, open)(::benchmark::State& state) {
   int i = 0;
 
   for (auto _ : state) {
-    auto r = fs->open(entries[i++ % NUM_ENTRIES]);
+    std::error_code ec;
+    auto r = fs->open(entries[i++ % NUM_ENTRIES], ec);
     ::benchmark::DoNotOptimize(r);
   }
 }

test/tool_main_test.cpp

@@ -2376,7 +2376,14 @@ TEST(mkdwarfs_test, filesystem_read_error) {
   auto iv = fs.find("/somedir");
   ASSERT_TRUE(iv);
   EXPECT_TRUE(iv->is_directory());
-  EXPECT_EQ(-1, fs.open(*iv));
+  EXPECT_THAT([&] { fs.open(*iv); }, ::testing::Throws<std::system_error>());
+  {
+    std::error_code ec;
+    auto res = fs.open(*iv, ec);
+    EXPECT_TRUE(ec);
+    EXPECT_EQ(EINVAL, ec.value());
+    EXPECT_EQ(0, res);
+  }
   {
     char buf[1];
     std::error_code ec;