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#include "nar-accessor.hh"
#include "archive.hh"
#include <map>
#include <stack>
#include <algorithm>
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;
/* If this is a directory, all the children of the directory. */
std::map<std::string, NarMember> children;
};
struct NarIndexer : ParseSink, StringSource
{
NarMember root;
std::stack<NarMember*> parents;
std::string currentStart;
bool isExec = false;
NarIndexer(const std::string & nar) : StringSource(nar)
{
}
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
{
createMember(path, {FSAccessor::Type::tDirectory, false, 0, 0 });
}
void createRegularFile(const Path & path) override
{
createMember(path, {FSAccessor::Type::tRegular, false, 0, 0 });
}
void isExecutable() override
{
parents.top()->isExecutable = true;
}
void preallocateContents(unsigned long long size) override
{
currentStart = string(s, pos, 16);
assert(size <= std::numeric_limits<size_t>::max());
parents.top()->size = (size_t)size;
parents.top()->start = pos;
}
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
{
createMember(path,
NarMember{FSAccessor::Type::tSymlink, false, 0, 0, target});
}
NarMember* find(const Path & path)
{
Path canon = path == "" ? "" : canonPath(path);
NarMember* current = &root;
auto end = path.end();
for(auto it = path.begin(); it != end; ) {
// because it != end, the remaining component is non-empty so we need
// a directory
if(current->type != FSAccessor::Type::tDirectory) return nullptr;
// skip slash (canonPath above ensures that this is always a slash)
assert(*it == '/');
it += 1;
// lookup current component
auto next = std::find(it, end, '/');
auto child = current->children.find(std::string(it, next));
if(child == current->children.end()) return nullptr;
current = &child->second;
it = next;
}
return current;
}
NarMember& at(const Path & path) {
auto result = find(path);
if(result == nullptr) {
throw Error(format("NAR file does not contain path '%1%'") % path);
}
return *result;
}
};
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.find(path);
if (i == nullptr)
return {FSAccessor::Type::tMissing, 0, false};
return {i->type, i->size, i->isExecutable};
}
StringSet readDirectory(const Path & path) override
{
auto i = indexer.at(path);
if (i.type != FSAccessor::Type::tDirectory)
throw Error(format("path '%1%' inside NAR file is not a directory") % path);
StringSet res;
for(auto&& child : i.children) {
res.insert(child.first);
}
return res;
}
std::string readFile(const Path & path) override
{
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.start, i.size);
}
std::string readLink(const Path & path) override
{
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.target;
}
};
ref<FSAccessor> makeNarAccessor(ref<const std::string> nar)
{
return make_ref<NarAccessor>(nar);
}
}
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