metadata_v2: implement get_chunks

include/dwarfs/metadata_v2.h

@@ -32,6 +32,7 @@
 #include <sys/statvfs.h>
 #include <sys/types.h>
 
+#include <boost/iterator/iterator_facade.hpp>
 #include <boost/range/irange.hpp>
 
 #include <folly/Expected.h>
@@ -84,6 +85,77 @@ class directory_view
       meta_;
 };
 
+using chunk_view = ::apache::thrift::frozen::View<thrift::metadata::chunk>;
+
+class chunk_range {
+ public:
+  class iterator
+      : public boost::iterator_facade<iterator, chunk_view const,
+                                      boost::random_access_traversal_tag> {
+   public:
+    iterator() = default;
+
+    iterator(::apache::thrift::frozen::MappedFrozen<
+                 thrift::metadata::metadata> const* meta,
+             uint32_t it)
+        : meta_(meta)
+        , it_(it) {}
+
+    iterator(iterator const& other)
+        : meta_(other.meta_)
+        , it_(other.it_) {}
+
+   private:
+    friend class boost::iterator_core_access;
+
+    bool equal(iterator const& other) const {
+      return meta_ == other.meta_ && it_ == other.it_;
+    }
+
+    void increment() { ++it_; }
+
+    void decrement() { --it_; }
+
+    void advance(difference_type n) { it_ += n; }
+
+    difference_type distance_to(iterator const& other) const {
+      return static_cast<difference_type>(other.it_) -
+             static_cast<difference_type>(it_);
+    }
+
+    chunk_view const& dereference() const {
+      view_ = meta_->chunks()[it_];
+      return view_;
+    }
+
+    ::apache::thrift::frozen::MappedFrozen<thrift::metadata::metadata> const*
+        meta_;
+    uint32_t it_{0};
+    mutable chunk_view view_;
+  };
+
+  chunk_range(::apache::thrift::frozen::MappedFrozen<
+                  thrift::metadata::metadata> const* meta,
+              uint32_t begin, uint32_t end)
+      : meta_(meta)
+      , begin_(begin)
+      , end_(end) {}
+
+  iterator begin() const { return iterator(meta_, begin_); }
+
+  iterator end() const { return iterator(meta_, end_); }
+
+  size_t size() const { return end_ - begin_; }
+
+  bool empty() const { return end_ == begin_; }
+
+ private:
+  ::apache::thrift::frozen::MappedFrozen<thrift::metadata::metadata> const*
+      meta_;
+  uint32_t begin_{0};
+  uint32_t end_{0};
+};
+
 class metadata_v2 {
  public:
   metadata_v2() = default;
@@ -150,15 +222,9 @@ class metadata_v2 {
 
   int statvfs(struct ::statvfs* stbuf) const { return impl_->statvfs(stbuf); }
 
-#if 0
-  size_t block_size() const { return impl_->block_size(); }
-
-  unsigned block_size_bits() const { return impl_->block_size_bits(); }
-
-  const chunk_type* get_chunks(int inode, size_t& num) const {
-    return impl_->get_chunks(inode, num);
+  std::optional<chunk_range> get_chunks(int inode) const {
+    return impl_->get_chunks(inode);
   }
-#endif
 
   class impl {
    public:
@@ -199,11 +265,7 @@ class metadata_v2 {
 
     virtual int statvfs(struct ::statvfs* stbuf) const = 0;
 
-#if 0
-    virtual size_t block_size() const = 0;
-    virtual unsigned block_size_bits() const = 0;
-    virtual const chunk_type* get_chunks(int inode, size_t& num) const = 0;
-#endif
+    virtual std::optional<chunk_range> get_chunks(int inode) const = 0;
   };
 
  private:

src/dwarfs/filesystem.cpp

@@ -23,6 +23,7 @@
 #include <cstring>
 
 #include <folly/Format.h>
+#include <folly/container/Enumerate.h>
 
 #include "dwarfs/block_cache.h"
 #include "dwarfs/config.h"
@@ -199,11 +200,17 @@ void filesystem_<LoggerPolicy>::dump(std::ostream& os) const {
 template <typename LoggerPolicy>
 void filesystem_<LoggerPolicy>::dump_v2(std::ostream& os) const {
   meta_v2_.dump(os, [&](const std::string& indent, uint32_t inode) {
-    size_t num = 0;
-    const chunk_type* chunk = meta_.get_chunks(inode, num); // TODO
+    auto chunks = meta_v2_.get_chunks(inode);
 
-    os << indent << num << " chunks in inode " << inode << "\n";
-    ir_.dump(os, indent + "  ", chunk, num);
+    if (chunks) {
+      os << indent << chunks->size() << " chunks in inode " << inode << "\n";
+      for (auto chunk : folly::enumerate(*chunks)) {
+        os << indent << "  [" << chunk.index << "] -> (" << chunk->block()
+           << ", " << chunk->offset() << ", " << chunk->size() << ")\n";
+      }
+    }
+
+    // ir_.dump(os, indent + "  ", chunk, num);  // TODO
   });
 }
 

src/dwarfs/metadata_v2.cpp

@@ -125,15 +125,7 @@ class metadata_v2_ : public metadata_v2::impl {
 
   int statvfs(struct ::statvfs* stbuf) const override;
 
-#if 0
-  size_t block_size() const override {
-    return static_cast<size_t>(1) << cfg_->block_size_bits;
-  }
-
-  unsigned block_size_bits() const override { return cfg_->block_size_bits; }
-
-  const chunk_type* get_chunks(int inode, size_t& num) const override;
-#endif
+  std::optional<chunk_range> get_chunks(int inode) const override;
 
  private:
   entry_view make_entry_view(size_t index) const {
@@ -189,7 +181,7 @@ class metadata_v2_ : public metadata_v2::impl {
   std::optional<entry_view> get_entry(int inode) const {
     inode -= inode_offset_;
     std::optional<entry_view> rv;
-    if (inode >= 0 && inode < int(meta_.entry_index().size())) {
+    if (inode >= 0 && inode < static_cast<int>(meta_.entry_index().size())) {
       rv = make_entry_view_from_inode(inode);
     }
     return rv;
@@ -200,12 +192,6 @@ class metadata_v2_ : public metadata_v2::impl {
         .links()[meta_.link_index()[entry.inode()] - meta_.link_index_offset()];
   }
 
-#if 0
-  const char* linkptr(entry_view entry) const {
-    return as<char>(entry->u.offset + sizeof(uint16_t));
-  }
-#endif
-
   std::vector<uint8_t> data_;
   ::apache::thrift::frozen::MappedFrozen<thrift::metadata::metadata> meta_;
   entry_view root_;
@@ -249,7 +235,7 @@ void metadata_v2_<LoggerPolicy>::dump(
   auto count = dir.entry_count();
   auto first = dir.first_entry();
 
-  os << indent << "(" << count << ") entries [" << dir.self_inode() << ":"
+  os << "(" << count << " entries) [" << dir.self_inode() << ", "
      << dir.parent_inode() << "]\n";
 
   for (size_t i = 0; i < count; ++i) {
@@ -505,22 +491,20 @@ int metadata_v2_<LoggerPolicy>::statvfs(struct ::statvfs* stbuf) const {
   return 0;
 }
 
-#if 0
 template <typename LoggerPolicy>
-const chunk_type*
-metadata_v2_<LoggerPolicy>::get_chunks(int inode, size_t& num) const {
-  inode -= inode_offset_;
-  if (inode < static_cast<int>(cfg_->chunk_index_offset) ||
-      inode >= static_cast<int>(cfg_->inode_count)) {
-    return nullptr;
+std::optional<chunk_range>
+metadata_v2_<LoggerPolicy>::get_chunks(int inode) const {
+  std::optional<chunk_range> rv;
+  inode -= inode_offset_ + meta_.chunk_index_offset();
+  if (inode >= 0 &&
+      inode < (static_cast<int>(meta_.chunk_index().size()) - 1)) {
+    uint32_t begin = meta_.chunk_index()[inode];
+    uint32_t end = meta_.chunk_index()[inode + 1];
+    rv = chunk_range(&meta_, begin, end);
   }
-  uint32_t off = chunk_index_[inode];
-  num = (chunk_index_[inode + 1] - off) / sizeof(chunk_type);
-  return as<chunk_type>(off);
+  return rv;
 }
 
-#endif
-
 void metadata_v2::get_stat_defaults(struct ::stat* defaults) {
   ::memset(defaults, 0, sizeof(struct ::stat));
   defaults->st_uid = ::geteuid();