lix/src/libutil/json.cc
Eelco Dolstra 57b9505731
nix search: Add a cache
The package list is now cached in
~/.cache/nix/package-search.json. This gives a substantial speedup to
"nix search" queries. For example (on an SSD):

First run: (no package search cache, cold page cache)

  $ time nix search blender
  Attribute name: nixpkgs.blender
  Package name: blender
  Version: 2.78c
  Description: 3D Creation/Animation/Publishing System

  real    0m6.516s

Second run: (package search cache populated)

  $ time nix search blender
  Attribute name: nixpkgs.blender
  Package name: blender
  Version: 2.78c
  Description: 3D Creation/Animation/Publishing System

  real    0m0.143s
2017-07-26 17:29:10 +02:00

174 lines
3.5 KiB
C++

#include "json.hh"
#include <iomanip>
#include <cstring>
namespace nix {
void toJSON(std::ostream & str, const char * start, const char * end)
{
str << '"';
for (auto i = start; i != end; i++)
if (*i == '\"' || *i == '\\') str << '\\' << *i;
else if (*i == '\n') str << "\\n";
else if (*i == '\r') str << "\\r";
else if (*i == '\t') str << "\\t";
else if (*i >= 0 && *i < 32)
str << "\\u" << std::setfill('0') << std::setw(4) << std::hex << (uint16_t) *i << std::dec;
else str << *i;
str << '"';
}
void toJSON(std::ostream & str, const char * s)
{
if (!s) str << "null"; else toJSON(str, s, s + strlen(s));
}
template<> void toJSON<int>(std::ostream & str, const int & n) { str << n; }
template<> void toJSON<unsigned int>(std::ostream & str, const unsigned int & n) { str << n; }
template<> void toJSON<long>(std::ostream & str, const long & n) { str << n; }
template<> void toJSON<unsigned long>(std::ostream & str, const unsigned long & n) { str << n; }
template<> void toJSON<long long>(std::ostream & str, const long long & n) { str << n; }
template<> void toJSON<unsigned long long>(std::ostream & str, const unsigned long long & n) { str << n; }
template<> void toJSON<float>(std::ostream & str, const float & n) { str << n; }
template<> void toJSON<std::string>(std::ostream & str, const std::string & s)
{
toJSON(str, s.c_str(), s.c_str() + s.size());
}
template<> void toJSON<bool>(std::ostream & str, const bool & b)
{
str << (b ? "true" : "false");
}
template<> void toJSON<std::nullptr_t>(std::ostream & str, const std::nullptr_t & b)
{
str << "null";
}
JSONWriter::JSONWriter(std::ostream & str, bool indent)
: state(new JSONState(str, indent))
{
state->stack++;
}
JSONWriter::JSONWriter(JSONState * state)
: state(state)
{
state->stack++;
}
JSONWriter::~JSONWriter()
{
if (state) {
assertActive();
state->stack--;
if (state->stack == 0) delete state;
}
}
void JSONWriter::comma()
{
assertActive();
if (first) {
first = false;
} else {
state->str << ',';
}
if (state->indent) indent();
}
void JSONWriter::indent()
{
state->str << '\n' << std::string(state->depth * 2, ' ');
}
void JSONList::open()
{
state->depth++;
state->str << '[';
}
JSONList::~JSONList()
{
state->depth--;
if (state->indent && !first) indent();
state->str << "]";
}
JSONList JSONList::list()
{
comma();
return JSONList(state);
}
JSONObject JSONList::object()
{
comma();
return JSONObject(state);
}
JSONPlaceholder JSONList::placeholder()
{
comma();
return JSONPlaceholder(state);
}
void JSONObject::open()
{
state->depth++;
state->str << '{';
}
JSONObject::~JSONObject()
{
if (state) {
state->depth--;
if (state->indent && !first) indent();
state->str << "}";
}
}
void JSONObject::attr(const std::string & s)
{
comma();
toJSON(state->str, s);
state->str << ':';
if (state->indent) state->str << ' ';
}
JSONList JSONObject::list(const std::string & name)
{
attr(name);
return JSONList(state);
}
JSONObject JSONObject::object(const std::string & name)
{
attr(name);
return JSONObject(state);
}
JSONPlaceholder JSONObject::placeholder(const std::string & name)
{
attr(name);
return JSONPlaceholder(state);
}
JSONList JSONPlaceholder::list()
{
assertValid();
first = false;
return JSONList(state);
}
JSONObject JSONPlaceholder::object()
{
assertValid();
first = false;
return JSONObject(state);
}
}