nixos/nix
1
1
Fork 0
mirror of https://github.com/NixOS/nix.git synced 2025-11-13 22:12:43 +01:00
Code Activity

NarAccessor: Run in constant memory

Browse source
This commit is contained in:
Eelco Dolstra 2020-07-13 17:30:42 +02:00
parent fc84c358d9
commit 0a9da00a10
7 changed files with 57 additions and 37 deletions
Download patch file Download diff file Expand all files Collapse all files

46
src/libstore/nar-accessor.cc
View file

@ -18,7 +18,7 @@ struct NarMember
/* If this is a regular file, position of the contents of this
file in the NAR. */
size_t start = 0, size = 0;
uint64_t start = 0, size = 0;
std::string target;
@ -34,17 +34,19 @@ struct NarAccessor : public FSAccessor
NarMember root;
struct NarIndexer : ParseSink, StringSource
struct NarIndexer : ParseSink, Source
{
NarAccessor & acc;
Source & source;
std::stack<NarMember *> parents;
std::string currentStart;
bool isExec = false;
NarIndexer(NarAccessor & acc, const std::string & nar)
: StringSource(nar), acc(acc)
uint64_t pos = 0;
NarIndexer(NarAccessor & acc, Source & source)
: acc(acc), source(source)
{ }
void createMember(const Path & path, NarMember member) {
@ -79,31 +81,38 @@ struct NarAccessor : public FSAccessor
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;
assert(size <= std::numeric_limits<uint64_t>::max());
parents.top()->size = (uint64_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});
}
size_t read(unsigned char * data, size_t len) override
{
auto n = source.read(data, len);
pos += n;
return n;
}
};
NarAccessor(ref<const std::string> nar) : nar(nar)
{
NarIndexer indexer(*this, *nar);
StringSource source(*nar);
NarIndexer indexer(*this, source);
parseDump(indexer, indexer);
}
NarAccessor(Source & source)
{
NarIndexer indexer(*this, source);
parseDump(indexer, indexer);
}
@ -219,6 +228,11 @@ ref<FSAccessor> makeNarAccessor(ref<const std::string> nar)
return make_ref<NarAccessor>(nar);
}
ref<FSAccessor> makeNarAccessor(Source & source)
{
return make_ref<NarAccessor>(source);
}
ref<FSAccessor> makeLazyNarAccessor(const std::string & listing,
GetNarBytes getNarBytes)
{