nar-accessor: use tree, fixes readDirectory missing children
Previously, if a directory `foo` existed and a file `foo-` (where `-` is any character that is sorted before `/`), then `readDirectory` would return an empty list. To fix this, we now use a tree where we can just access the children of the node, and do not need to rely on sorting behavior to list the contents of a directory.
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					 1 changed files with 76 additions and 33 deletions
				
			
		|  | @ -2,6 +2,8 @@ | |||
| #include "archive.hh" | ||||
| 
 | ||||
| #include <map> | ||||
| #include <stack> | ||||
| #include <algorithm> | ||||
| 
 | ||||
| namespace nix { | ||||
| 
 | ||||
|  | @ -16,16 +18,36 @@ struct NarMember | |||
|     size_t start, size; | ||||
| 
 | ||||
|     std::string target; | ||||
| 
 | ||||
|     /* If this is a directory, all the children of the directory. */ | ||||
|     std::map<std::string, NarMember> children; | ||||
| 
 | ||||
|     NarMember* find(const Path & path) | ||||
|     { | ||||
|         if(path == "") return this; | ||||
| 
 | ||||
|         if(type != FSAccessor::Type::tDirectory) { | ||||
|             return nullptr; | ||||
|         } | ||||
| 
 | ||||
|         auto split = std::find(path.begin() + 1, path.end(), '/'); | ||||
|         std::string child_name(path.begin() + 1, split); | ||||
|         std::string remaining(split, path.end()); | ||||
| 
 | ||||
|         auto child = children.find(child_name); | ||||
|         if(child == children.end()) return nullptr; | ||||
| 
 | ||||
|         return child->second.find(remaining); | ||||
|     } | ||||
| 
 | ||||
| }; | ||||
| 
 | ||||
| struct NarIndexer : ParseSink, StringSource | ||||
| { | ||||
|     // FIXME: should store this as a tree. Now we're vulnerable to
 | ||||
|     // O(nm) memory consumption (e.g. for x_0/.../x_n/{y_0..y_m}).
 | ||||
|     typedef std::map<Path, NarMember> Members; | ||||
|     Members members; | ||||
|     NarMember root; | ||||
|     std::stack<NarMember*> parents; | ||||
| 
 | ||||
|     Path currentPath; | ||||
|     std::string currentName; | ||||
|     std::string currentStart; | ||||
|     bool isExec = false; | ||||
| 
 | ||||
|  | @ -33,28 +55,45 @@ struct NarIndexer : ParseSink, StringSource | |||
|     { | ||||
|     } | ||||
| 
 | ||||
|     void createMember(const Path & path, NarMember member) { | ||||
|         size_t level = std::count(path.begin(), path.end(), '/'); | ||||
|         while(parents.size() > level) { | ||||
|             parents.pop(); | ||||
|         } | ||||
| 
 | ||||
|         if(parents.empty()) { | ||||
|             root = std::move(member); | ||||
|             parents.push(&root); | ||||
|         } else { | ||||
|             if(parents.top()->type != FSAccessor::Type::tDirectory) { | ||||
|                 throw Error(format("NAR file missing parent directory of path ‘%1%’") % path); | ||||
|             } | ||||
|             auto result = parents.top()->children.emplace(baseNameOf(path), std::move(member)); | ||||
|             parents.push(&result.first->second); | ||||
|         } | ||||
|     } | ||||
| 
 | ||||
|     void createDirectory(const Path & path) override | ||||
|     { | ||||
|         members.emplace(path, | ||||
|             NarMember{FSAccessor::Type::tDirectory, false, 0, 0}); | ||||
|         createMember(path, {FSAccessor::Type::tDirectory, false, 0, 0 });  | ||||
|     } | ||||
| 
 | ||||
|     void createRegularFile(const Path & path) override | ||||
|     { | ||||
|         currentPath = path; | ||||
|         createMember(path, {FSAccessor::Type::tRegular, false, 0, 0 }); | ||||
|     } | ||||
| 
 | ||||
|     void isExecutable() override | ||||
|     { | ||||
|         isExec = true; | ||||
|         parents.top()->isExecutable = true; | ||||
|     } | ||||
| 
 | ||||
|     void preallocateContents(unsigned long long size) override | ||||
|     { | ||||
|         currentStart = string(s, pos, 16); | ||||
|         assert(size <= std::numeric_limits<size_t>::max()); | ||||
|         members.emplace(currentPath, | ||||
|             NarMember{FSAccessor::Type::tRegular, isExec, pos, (size_t) size}); | ||||
|         parents.top()->size = (size_t)size; | ||||
|         parents.top()->start = pos; | ||||
|     } | ||||
| 
 | ||||
|     void receiveContents(unsigned char * data, unsigned int len) override | ||||
|  | @ -68,16 +107,23 @@ struct NarIndexer : ParseSink, StringSource | |||
| 
 | ||||
|     void createSymlink(const Path & path, const string & target) override | ||||
|     { | ||||
|         members.emplace(path, | ||||
|         createMember(path, | ||||
|             NarMember{FSAccessor::Type::tSymlink, false, 0, 0, target}); | ||||
|     } | ||||
| 
 | ||||
|     Members::iterator find(const Path & path) | ||||
|     NarMember* find(const Path & path) | ||||
|     { | ||||
|         auto i = members.find(path); | ||||
|         if (i == members.end()) | ||||
|         Path canon = path == "" ? "" : canonPath(path); | ||||
|         NarMember* result = root.find(canon); | ||||
|         return result; | ||||
|     } | ||||
| 
 | ||||
|     NarMember& at(const Path & path) { | ||||
|         auto result = find(path); | ||||
|         if(result == nullptr) { | ||||
|             throw Error(format("NAR file does not contain path ‘%1%’") % path); | ||||
|         return i; | ||||
|         } | ||||
|         return *result; | ||||
|     } | ||||
| }; | ||||
| 
 | ||||
|  | @ -93,44 +139,41 @@ struct NarAccessor : public FSAccessor | |||
| 
 | ||||
|     Stat stat(const Path & path) override | ||||
|     { | ||||
|         auto i = indexer.members.find(path); | ||||
|         if (i == indexer.members.end()) | ||||
|         auto i = indexer.find(path); | ||||
|         if (i == nullptr) | ||||
|             return {FSAccessor::Type::tMissing, 0, false}; | ||||
|         return {i->second.type, i->second.size, i->second.isExecutable}; | ||||
|         return {i->type, i->size, i->isExecutable}; | ||||
|     } | ||||
| 
 | ||||
|     StringSet readDirectory(const Path & path) override | ||||
|     { | ||||
|         auto i = indexer.find(path); | ||||
|         auto i = indexer.at(path); | ||||
| 
 | ||||
|         if (i->second.type != FSAccessor::Type::tDirectory) | ||||
|         if (i.type != FSAccessor::Type::tDirectory) | ||||
|             throw Error(format("path ‘%1%’ inside NAR file is not a directory") % path); | ||||
| 
 | ||||
|         ++i; | ||||
|         StringSet res; | ||||
|         while (i != indexer.members.end() && isInDir(i->first, path)) { | ||||
|             // FIXME: really bad performance.
 | ||||
|             if (i->first.find('/', path.size() + 1) == std::string::npos) | ||||
|                 res.insert(std::string(i->first, path.size() + 1)); | ||||
|             ++i; | ||||
|         for(auto&& child : i.children) { | ||||
|             res.insert(child.first); | ||||
| 
 | ||||
|         } | ||||
|         return res; | ||||
|     } | ||||
| 
 | ||||
|     std::string readFile(const Path & path) override | ||||
|     { | ||||
|         auto i = indexer.find(path); | ||||
|         if (i->second.type != FSAccessor::Type::tRegular) | ||||
|         auto i = indexer.at(path); | ||||
|         if (i.type != FSAccessor::Type::tRegular) | ||||
|             throw Error(format("path ‘%1%’ inside NAR file is not a regular file") % path); | ||||
|         return std::string(*nar, i->second.start, i->second.size); | ||||
|         return std::string(*nar, i.start, i.size); | ||||
|     } | ||||
| 
 | ||||
|     std::string readLink(const Path & path) override | ||||
|     { | ||||
|         auto i = indexer.find(path); | ||||
|         if (i->second.type != FSAccessor::Type::tSymlink) | ||||
|         auto i = indexer.at(path); | ||||
|         if (i.type != FSAccessor::Type::tSymlink) | ||||
|             throw Error(format("path ‘%1%’ inside NAR file is not a symlink") % path); | ||||
|         return i->second.target; | ||||
|         return i.target; | ||||
|     } | ||||
| }; | ||||
| 
 | ||||
|  |  | |||
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