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#include "nar-accessor.hh"
#include "archive.hh"
#include <map>
namespace nix {
struct NarMember
{
FSAccessor::Type type;
bool isExecutable;
/* If this is a regular file, position of the contents of this
file in the NAR. */
size_t start, size;
std::string target;
};
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;
Path currentPath;
std::string currentStart;
bool isExec = false;
NarIndexer(const std::string & nar) : StringSource(nar)
{
}
void createDirectory(const Path & path) override
{
members.emplace(path,
NarMember{FSAccessor::Type::tDirectory, false, 0, 0});
}
void createRegularFile(const Path & path) override
{
currentPath = path;
}
void isExecutable() override
{
isExec = 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});
}
void receiveContents(unsigned char * data, unsigned int len) override
{
// Sanity check
if (!currentStart.empty()) {
assert(len < 16 || currentStart == string((char *) data, 16));
currentStart.clear();
}
}
void createSymlink(const Path & path, const string & target) override
{
members.emplace(path,
NarMember{FSAccessor::Type::tSymlink, false, 0, 0, target});
}
Members::iterator find(const Path & path)
{
auto i = members.find(path);
if (i == members.end())
throw Error(format("NAR file does not contain path ‘%1%’") % path);
return i;
}
};
struct NarAccessor : public FSAccessor
{
ref<const std::string> nar;
NarIndexer indexer;
NarAccessor(ref<const std::string> nar) : nar(nar), indexer(*nar)
{
parseDump(indexer, indexer);
}
Stat stat(const Path & path) override
{
auto i = indexer.members.find(path);
if (i == indexer.members.end())
return {FSAccessor::Type::tMissing, 0, false};
return {i->second.type, i->second.size, i->second.isExecutable};
}
StringSet readDirectory(const Path & path) override
{
auto i = indexer.find(path);
if (i->second.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;
}
return res;
}
std::string readFile(const Path & path) override
{
auto i = indexer.find(path);
if (i->second.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);
}
std::string readLink(const Path & path) override
{
auto i = indexer.find(path);
if (i->second.type != FSAccessor::Type::tSymlink)
throw Error(format("path ‘%1%’ inside NAR file is not a symlink") % path);
return i->second.target;
}
};
ref<FSAccessor> makeNarAccessor(ref<const std::string> nar)
{
return make_ref<NarAccessor>(nar);
}
}
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