lix/src/nix/search.cc
Jörg Thalheim 85c1932c94
nix/search: no error for empty search results if json is enabled
- result list will be always empty if --json is passed
- for scripts an empty search result is not really an error,
  we rather want to distinguish between evaluation errors and empty results
2020-05-06 14:43:54 +01:00

278 lines
9.1 KiB
C++

#include "command.hh"
#include "globals.hh"
#include "eval.hh"
#include "eval-inline.hh"
#include "names.hh"
#include "get-drvs.hh"
#include "common-args.hh"
#include "json.hh"
#include "json-to-value.hh"
#include "shared.hh"
#include <regex>
#include <fstream>
using namespace nix;
std::string wrap(std::string prefix, std::string s)
{
return prefix + s + ANSI_NORMAL;
}
std::string hilite(const std::string & s, const std::smatch & m, std::string postfix)
{
return
m.empty()
? s
: std::string(m.prefix())
+ ANSI_RED + std::string(m.str()) + postfix
+ std::string(m.suffix());
}
struct CmdSearch : SourceExprCommand, MixJSON
{
std::vector<std::string> res;
bool writeCache = true;
bool useCache = true;
CmdSearch()
{
expectArgs("regex", &res);
addFlag({
.longName = "update-cache",
.shortName = 'u',
.description = "update the package search cache",
.handler = {[&]() { writeCache = true; useCache = false; }}
});
addFlag({
.longName = "no-cache",
.description = "do not use or update the package search cache",
.handler = {[&]() { writeCache = false; useCache = false; }}
});
}
std::string description() override
{
return "query available packages";
}
Examples examples() override
{
return {
Example{
"To show all available packages:",
"nix search"
},
Example{
"To show any packages containing 'blender' in its name or description:",
"nix search blender"
},
Example{
"To search for Firefox or Chromium:",
"nix search 'firefox|chromium'"
},
Example{
"To search for git and frontend or gui:",
"nix search git 'frontend|gui'"
}
};
}
void run(ref<Store> store) override
{
settings.readOnlyMode = true;
// Empty search string should match all packages
// Use "^" here instead of ".*" due to differences in resulting highlighting
// (see #1893 -- libc++ claims empty search string is not in POSIX grammar)
if (res.empty()) {
res.push_back("^");
}
std::vector<std::regex> regexes;
regexes.reserve(res.size());
for (auto &re : res) {
regexes.push_back(std::regex(re, std::regex::extended | std::regex::icase));
}
auto state = getEvalState();
auto jsonOut = json ? std::make_unique<JSONObject>(std::cout) : nullptr;
auto sToplevel = state->symbols.create("_toplevel");
auto sRecurse = state->symbols.create("recurseForDerivations");
bool fromCache = false;
std::map<std::string, std::string> results;
std::function<void(Value *, std::string, bool, JSONObject *)> doExpr;
doExpr = [&](Value * v, std::string attrPath, bool toplevel, JSONObject * cache) {
debug("at attribute '%s'", attrPath);
try {
uint found = 0;
state->forceValue(*v);
if (v->type == tLambda && toplevel) {
Value * v2 = state->allocValue();
state->autoCallFunction(*state->allocBindings(1), *v, *v2);
v = v2;
state->forceValue(*v);
}
if (state->isDerivation(*v)) {
DrvInfo drv(*state, attrPath, v->attrs);
std::string description;
std::smatch attrPathMatch;
std::smatch descriptionMatch;
std::smatch nameMatch;
std::string name;
DrvName parsed(drv.queryName());
for (auto &regex : regexes) {
std::regex_search(attrPath, attrPathMatch, regex);
name = parsed.name;
std::regex_search(name, nameMatch, regex);
description = drv.queryMetaString("description");
std::replace(description.begin(), description.end(), '\n', ' ');
std::regex_search(description, descriptionMatch, regex);
if (!attrPathMatch.empty()
|| !nameMatch.empty()
|| !descriptionMatch.empty())
{
found++;
}
}
if (found == res.size()) {
if (json) {
auto jsonElem = jsonOut->object(attrPath);
jsonElem.attr("pkgName", parsed.name);
jsonElem.attr("version", parsed.version);
jsonElem.attr("description", description);
} else {
auto name = hilite(parsed.name, nameMatch, "\e[0;2m")
+ std::string(parsed.fullName, parsed.name.length());
results[attrPath] = fmt(
"* %s (%s)\n %s\n",
wrap("\e[0;1m", hilite(attrPath, attrPathMatch, "\e[0;1m")),
wrap("\e[0;2m", hilite(name, nameMatch, "\e[0;2m")),
hilite(description, descriptionMatch, ANSI_NORMAL));
}
}
if (cache) {
cache->attr("type", "derivation");
cache->attr("name", drv.queryName());
cache->attr("system", drv.querySystem());
if (description != "") {
auto meta(cache->object("meta"));
meta.attr("description", description);
}
}
}
else if (v->type == tAttrs) {
if (!toplevel) {
auto attrs = v->attrs;
Bindings::iterator j = attrs->find(sRecurse);
if (j == attrs->end() || !state->forceBool(*j->value, *j->pos)) {
debug("skip attribute '%s'", attrPath);
return;
}
}
bool toplevel2 = false;
if (!fromCache) {
Bindings::iterator j = v->attrs->find(sToplevel);
toplevel2 = j != v->attrs->end() && state->forceBool(*j->value, *j->pos);
}
for (auto & i : *v->attrs) {
auto cache2 =
cache ? std::make_unique<JSONObject>(cache->object(i.name)) : nullptr;
doExpr(i.value,
attrPath == "" ? (std::string) i.name : attrPath + "." + (std::string) i.name,
toplevel2 || fromCache, cache2 ? cache2.get() : nullptr);
}
}
} catch (AssertionError & e) {
} catch (Error & e) {
if (!toplevel) {
e.addPrefix(fmt("While evaluating the attribute '%s':\n", attrPath));
throw;
}
}
};
Path jsonCacheFileName = getCacheDir() + "/nix/package-search.json";
if (useCache && pathExists(jsonCacheFileName)) {
warn("using cached results; pass '-u' to update the cache");
Value vRoot;
parseJSON(*state, readFile(jsonCacheFileName), vRoot);
fromCache = true;
doExpr(&vRoot, "", true, nullptr);
}
else {
createDirs(dirOf(jsonCacheFileName));
Path tmpFile = fmt("%s.tmp.%d", jsonCacheFileName, getpid());
std::ofstream jsonCacheFile;
try {
// iostream considered harmful
jsonCacheFile.exceptions(std::ofstream::failbit);
jsonCacheFile.open(tmpFile);
auto cache = writeCache ? std::make_unique<JSONObject>(jsonCacheFile, false) : nullptr;
doExpr(getSourceExpr(*state), "", true, cache.get());
} catch (std::exception &) {
/* Fun fact: catching std::ios::failure does not work
due to C++11 ABI shenanigans.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66145 */
if (!jsonCacheFile)
throw Error("error writing to %s", tmpFile);
throw;
}
if (writeCache && rename(tmpFile.c_str(), jsonCacheFileName.c_str()) == -1)
throw SysError("cannot rename '%s' to '%s'", tmpFile, jsonCacheFileName);
}
if (!json && results.size() == 0)
throw Error("no results for the given search term(s)!");
RunPager pager;
for (auto el : results) std::cout << el.second << "\n";
}
};
static auto r1 = registerCommand<CmdSearch>("search");