bkietz commented on a change in pull request #8187:
URL: https://github.com/apache/arrow/pull/8187#discussion_r494388617
##########
File path: cpp/src/arrow/filesystem/filesystem.cc
##########
@@ -457,18 +458,52 @@ Status CopyFiles(const std::vector<FileLocator>& sources,
ARROW_ASSIGN_OR_RAISE(auto source,
sources[i].filesystem->OpenInputStream(sources[i].path));
- auto dest_dir =
internal::GetAbstractPathParent(destinations[i].path).first;
- if (!dest_dir.empty()) {
- RETURN_NOT_OK(destinations[i].filesystem->CreateDir(dest_dir));
- }
-
ARROW_ASSIGN_OR_RAISE(
auto destination,
destinations[i].filesystem->OpenOutputStream(destinations[i].path));
return internal::CopyStream(source, destination, chunk_size);
});
}
+Status CopyFiles(const std::shared_ptr<FileSystem>& source_fs,
+ const FileSelector& source_sel,
+ const std::shared_ptr<FileSystem>& destination_fs,
+ const std::string& destination_base_dir, int64_t chunk_size,
+ bool use_threads) {
+ ARROW_ASSIGN_OR_RAISE(auto source_infos, source_fs->GetFileInfo(source_sel));
+ std::vector<FileLocator> sources, destinations;
+
+ std::unordered_set<std::string> destination_dirs;
+ destination_dirs.insert(destination_base_dir);
+
+ for (const FileInfo& source_info : source_infos) {
+ auto relative = internal::RemoveAncestor(source_sel.base_dir,
source_info.path());
+ if (!relative.has_value()) {
+ return Status::Invalid("GetFileInfo() yielded path '",
source_info.path(),
+ "', which is outside base dir '",
source_sel.base_dir, "'");
+ }
+
+ auto destination_path =
+ internal::ConcatAbstractPath(destination_base_dir,
relative->to_string());
+
+ if (source_info.IsDirectory()) {
+ destination_dirs.insert(destination_path);
+ } else if (source_info.IsFile()) {
+ sources.push_back({source_fs, source_info.path()});
+ destinations.push_back({destination_fs, destination_path});
+ }
+ }
+
+ std::vector<std::string> dirs(destination_dirs.size());
+ std::move(destination_dirs.begin(), destination_dirs.end(), dirs.begin());
+ RETURN_NOT_OK(::arrow::internal::OptionalParallelFor(
+ use_threads, static_cast<int>(dirs.size()), [&](int i) {
+ return dirs[i].empty() ? Status::OK() :
destination_fs->CreateDir(dirs[i]);
Review comment:
I'll remove any directories which have a descendant in the set, that
should produce the minimal number of directories to create.
##########
File path: cpp/src/arrow/filesystem/filesystem.cc
##########
@@ -487,15 +489,27 @@ Status CopyFiles(const std::shared_ptr<FileSystem>&
source_fs,
internal::ConcatAbstractPath(destination_base_dir,
relative->to_string());
if (source_info.IsDirectory()) {
- destination_dirs.insert(destination_path);
+ dirs.push_back(destination_path);
} else if (source_info.IsFile()) {
sources.push_back({source_fs, source_info.path()});
destinations.push_back({destination_fs, destination_path});
}
}
- std::vector<std::string> dirs(destination_dirs.size());
- std::move(destination_dirs.begin(), destination_dirs.end(), dirs.begin());
+ // remove directories with descendants since recursive directory creation
will create
+ // them automatically
+ std::sort(dirs.begin(), dirs.end());
+ for (auto ancestor = dirs.begin(); ancestor != dirs.end(); ++ancestor) {
+ auto descendants_end = ancestor + 1;
+
+ while (descendants_end != dirs.end() &&
+ internal::IsAncestorOf(*ancestor, *descendants_end)) {
+ ++descendants_end;
+ }
+
+ dirs.erase(ancestor, descendants_end - 1);
Review comment:
no, `dirs.erase(ancestor, descendants_end)` would erase "a/b" too but I
subtract 1 so it leaves the last descendant in place
##########
File path: cpp/src/arrow/filesystem/filesystem.cc
##########
@@ -487,15 +489,27 @@ Status CopyFiles(const std::shared_ptr<FileSystem>&
source_fs,
internal::ConcatAbstractPath(destination_base_dir,
relative->to_string());
if (source_info.IsDirectory()) {
- destination_dirs.insert(destination_path);
+ dirs.push_back(destination_path);
} else if (source_info.IsFile()) {
sources.push_back({source_fs, source_info.path()});
destinations.push_back({destination_fs, destination_path});
}
}
- std::vector<std::string> dirs(destination_dirs.size());
- std::move(destination_dirs.begin(), destination_dirs.end(), dirs.begin());
+ // remove directories with descendants since recursive directory creation
will create
+ // them automatically
+ std::sort(dirs.begin(), dirs.end());
+ for (auto ancestor = dirs.begin(); ancestor != dirs.end(); ++ancestor) {
+ auto descendants_end = ancestor + 1;
+
+ while (descendants_end != dirs.end() &&
+ internal::IsAncestorOf(*ancestor, *descendants_end)) {
+ ++descendants_end;
+ }
+
+ dirs.erase(ancestor, descendants_end - 1);
Review comment:
> Perhaps `PathForest` can help. Though it's not obvious how to list the
leaves.
I don't think so; the intent of PathForest is to visit all ancestors
efficiently so getting a minimal set of descendants would not be efficient
> `internal::IsAncestorOf(*(descendants_end - 1), *descendants_end)`
You're right, thanks
> Another problem is that you're iterating on dirs while erasing from it.
That's not safe, I think, unless you write `ancestor = dirs.erase(ancestor,
descendants_end - 1)`.
You're right; vector::erase invalidates iterators *at* or after the
beginning of the range.
> Yet another issue is if you have {"a", "a/b/c"}, "a" won't be removed?
No, I'd expect `IsAncestorOf("a", "a/b/c") so "a" should be removed.
##########
File path: cpp/src/arrow/filesystem/filesystem.cc
##########
@@ -487,15 +489,27 @@ Status CopyFiles(const std::shared_ptr<FileSystem>&
source_fs,
internal::ConcatAbstractPath(destination_base_dir,
relative->to_string());
if (source_info.IsDirectory()) {
- destination_dirs.insert(destination_path);
+ dirs.push_back(destination_path);
} else if (source_info.IsFile()) {
sources.push_back({source_fs, source_info.path()});
destinations.push_back({destination_fs, destination_path});
}
}
- std::vector<std::string> dirs(destination_dirs.size());
- std::move(destination_dirs.begin(), destination_dirs.end(), dirs.begin());
+ // remove directories with descendants since recursive directory creation
will create
+ // them automatically
+ std::sort(dirs.begin(), dirs.end());
+ for (auto ancestor = dirs.begin(); ancestor != dirs.end(); ++ancestor) {
+ auto descendants_end = ancestor + 1;
+
+ while (descendants_end != dirs.end() &&
+ internal::IsAncestorOf(*ancestor, *descendants_end)) {
+ ++descendants_end;
+ }
+
+ dirs.erase(ancestor, descendants_end - 1);
Review comment:
> Perhaps `PathForest` can help. Though it's not obvious how to list the
leaves.
I don't think so; the intent of PathForest is to visit all ancestors
efficiently so getting a minimal set of descendants would not be efficient
> `internal::IsAncestorOf(*(descendants_end - 1), *descendants_end)`
You're right, thanks
> Another problem is that you're iterating on dirs while erasing from it.
That's not safe, I think, unless you write `ancestor = dirs.erase(ancestor,
descendants_end - 1)`.
You're right; vector::erase invalidates iterators *at* or after the
beginning of the range.
> Yet another issue is if you have {"a", "a/b/c"}, "a" won't be removed?
No, I'd expect `IsAncestorOf("a", "a/b/c") so "a" should be removed.
##########
File path: cpp/src/arrow/filesystem/filesystem.cc
##########
@@ -487,15 +489,27 @@ Status CopyFiles(const std::shared_ptr<FileSystem>&
source_fs,
internal::ConcatAbstractPath(destination_base_dir,
relative->to_string());
if (source_info.IsDirectory()) {
- destination_dirs.insert(destination_path);
+ dirs.push_back(destination_path);
} else if (source_info.IsFile()) {
sources.push_back({source_fs, source_info.path()});
destinations.push_back({destination_fs, destination_path});
}
}
- std::vector<std::string> dirs(destination_dirs.size());
- std::move(destination_dirs.begin(), destination_dirs.end(), dirs.begin());
+ // remove directories with descendants since recursive directory creation
will create
+ // them automatically
+ std::sort(dirs.begin(), dirs.end());
+ for (auto ancestor = dirs.begin(); ancestor != dirs.end(); ++ancestor) {
+ auto descendants_end = ancestor + 1;
+
+ while (descendants_end != dirs.end() &&
+ internal::IsAncestorOf(*ancestor, *descendants_end)) {
+ ++descendants_end;
+ }
+
+ dirs.erase(ancestor, descendants_end - 1);
Review comment:
> Perhaps `PathForest` can help. Though it's not obvious how to list the
leaves.
I don't think so; the intent of PathForest is to visit all ancestors
efficiently so getting a minimal set of descendants would not be efficient
> `internal::IsAncestorOf(*(descendants_end - 1), *descendants_end)`
You're right, thanks
> Another problem is that you're iterating on dirs while erasing from it.
That's not safe, I think, unless you write `ancestor = dirs.erase(ancestor,
descendants_end - 1)`.
You're right; vector::erase invalidates iterators *at* or after the
beginning of the range.
> Yet another issue is if you have {"a", "a/b/c"}, "a" won't be removed?
No, I'd expect `IsAncestorOf("a", "a/b/c")` so "a" should be removed.
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