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nix why-depends: Add option to show all edges causing a dependency

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For example, without --all:

  $ nix why-depends nixpkgs.nixUnstable nixpkgs.libssh2
  /nix/store/s9n5gvj2l49b4n19nz6xl832654nf7n7-nix-1.12pre5511_c94f3d55
  └───lib/libnixstore.so: …/lib:/nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0/lib…
      => /nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0
      └───lib/libcurl.la: …ib -L/nix/store/4mbayl1y5hpjbjzkx8ndyhkv98kqw1wi-libssh2-1.8.0/l…
          => /nix/store/4mbayl1y5hpjbjzkx8ndyhkv98kqw1wi-libssh2-1.8.0

but with --all:

  $ nix why-depends -a nixpkgs.nixUnstable nixpkgs.libssh2
  /nix/store/s9n5gvj2l49b4n19nz6xl832654nf7n7-nix-1.12pre5511_c94f3d55
  ├───lib/libnixstore.so: …/lib:/nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0/lib…
  │   => /nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0
  │   └───lib/libcurl.la: …ib -L/nix/store/4mbayl1y5hpjbjzkx8ndyhkv98kqw1wi-libssh2-1.8.0/l…
  │       lib/libcurl.so.4.4.0: …/lib:/nix/store/4mbayl1y5hpjbjzkx8ndyhkv98kqw1wi-libssh2-1.8.0/l…
  │       => /nix/store/4mbayl1y5hpjbjzkx8ndyhkv98kqw1wi-libssh2-1.8.0
  └───lib/libnixstore.so: …/lib:/nix/store/bx2i9vi76lps6w9rr73fxf6my31s4dg5-aws-sdk-cpp-1.0…
      => /nix/store/bx2i9vi76lps6w9rr73fxf6my31s4dg5-aws-sdk-cpp-1.0.153
      └───lib/libaws-cpp-sdk-core.so: …e.so./nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0/lib…
          lib/libaws-cpp-sdk-s3.so: …/lib:/nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0/lib…
          => /nix/store/w9ykqpl5v0r3vfwsgn408jqhs72cx96x-curl-7.55.0
This commit is contained in:
Eelco Dolstra 2017-09-11 16:21:27 +02:00
parent d41c5eb13f
commit fc0ded3408
No known key found for this signature in database
GPG key ID: 8170B4726D7198DE
1 changed files with 156 additions and 34 deletions
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190
src/nix/why-depends.cc
View file

@ -5,26 +5,44 @@
#include "progress-bar.hh"
#include "fs-accessor.hh"
#include <queue>
using namespace nix;
static std::string hilite(const std::string & s, size_t pos, size_t len)
static std::string hilite(const std::string & s, size_t pos, size_t len,
const std::string & colour = ANSI_RED)
{
return
std::string(s, 0, pos)
+ ANSI_RED
+ colour
+ std::string(s, pos, len)
+ ANSI_NORMAL
+ std::string(s, pos + len);
}
static std::string filterPrintable(const std::string & s)
{
std::string res;
for (char c : s)
res += isprint(c) ? c : '.';
return res;
}
struct CmdWhyDepends : SourceExprCommand
{
std::string _package, _dependency;
bool all = false;
CmdWhyDepends()
{
expectArg("package", &_package);
expectArg("dependency", &_dependency);
mkFlag()
.longName("all")
.shortName('a')
.description("show all edges in the dependency graph leading from 'package' to 'dependency', rather than just a shortest path")
.set(&all, true);
}
std::string name() override
@ -67,66 +85,170 @@ struct CmdWhyDepends : SourceExprCommand
auto accessor = store->getFSAccessor();
// FIXME: show the path through the dependency graph.
auto const inf = std::numeric_limits<size_t>::max();
bool first = true;
struct Node
{
Path path;
PathSet refs;
PathSet rrefs;
size_t dist = inf;
Node * prev = nullptr;
bool queued = false;
bool visited = false;
};
for (auto & path : closure) {
std::map<Path, Node> graph;
if (path == dependencyPath && packagePath != dependencyPath)
continue;
for (auto & path : closure)
graph.emplace(path, Node{path, store->queryPathInfo(path)->references});
if (!store->queryPathInfo(path)->references.count(dependencyPath))
continue;
// Transpose the graph.
for (auto & node : graph)
for (auto & ref : node.second.refs)
graph[ref].rrefs.insert(node.first);
if (!first) std::cerr << "\n";
first = false;
/* Run Dijkstra's shortest path algorithm to get the distance
of every path in the closure to 'dependency'. */
graph[dependencyPath].dist = 0;
std::cerr << fmt("%s:\n", path);
std::priority_queue<Node *> queue;
std::function<void(const Path &)> recurse;
queue.push(&graph.at(dependencyPath));
recurse = [&](const Path & p) {
while (!queue.empty()) {
auto & node = *queue.top();
queue.pop();
for (auto & rref : node.rrefs) {
auto & node2 = graph.at(rref);
auto dist = node.dist + 1;
if (dist < node2.dist) {
node2.dist = dist;
node2.prev = &node;
if (!node2.queued) {
node2.queued = true;
queue.push(&node2);
}
}
}
}
/* Print the subgraph of nodes that have 'dependency' in their
closure (i.e., that have a non-infinite distance to
'dependency'). Print every edge on a path between `package`
and `dependency`. */
std::function<void(Node &, const string &, const string &)> printNode;
const string treeConn = "├───";
const string treeLast = "└───";
const string treeLine = "│ ";
const string treeNull = " ";
struct BailOut { };
printNode = [&](Node & node, const string & firstPad, const string & tailPad) {
assert(node.dist != inf);
std::cerr << fmt("%s%s%s%s" ANSI_NORMAL "\n",
firstPad,
node.visited ? "\e[38;5;244m" : "",
firstPad != "" ? "=> " : "",
node.path);
if (node.path == dependencyPath && !all) throw BailOut();
if (node.visited) return;
node.visited = true;
/* Sort the references by distance to `dependency` to
ensure that the shortest path is printed first. */
std::multimap<size_t, Node *> refs;
std::set<std::string> hashes;
for (auto & ref : node.refs) {
if (ref == node.path) continue;
auto & node2 = graph.at(ref);
if (node2.dist == inf) continue;
refs.emplace(node2.dist, &node2);
hashes.insert(storePathToHash(node2.path));
}
/* For each reference, find the files and symlinks that
contain the reference. */
std::map<std::string, Strings> hits;
std::function<void(const Path &)> visitPath;
visitPath = [&](const Path & p) {
auto st = accessor->stat(p);
auto p2 = p == path ? "/" : std::string(p, path.size() + 1);
auto p2 = p == node.path ? "/" : std::string(p, node.path.size() + 1);
auto getColour = [&](const std::string & hash) {
return hash == dependencyPathHash ? ANSI_GREEN : ANSI_BLUE;
};
if (st.type == FSAccessor::Type::tDirectory) {
auto names = accessor->readDirectory(p);
for (auto & name : names)
recurse(p + "/" + name);
visitPath(p + "/" + name);
}
else if (st.type == FSAccessor::Type::tRegular) {
auto contents = accessor->readFile(p);
auto pos = contents.find(dependencyPathHash);
if (pos != std::string::npos) {
size_t margin = 16;
auto pos2 = pos >= margin ? pos - margin : 0;
std::string fragment;
for (char c : std::string(contents, pos2,
pos - pos2 + dependencyPathHash.size() + margin))
{
fragment += isprint(c) ? c : '.';
}
std::cerr << fmt(" %s: …%s…\n",
p2,
hilite(fragment, pos - pos2, storePathHashLen));
for (auto & hash : hashes) {
auto pos = contents.find(hash);
if (pos != std::string::npos) {
size_t margin = 16;
auto pos2 = pos >= margin ? pos - margin : 0;
hits[hash].emplace_back(fmt("%s: …%s…\n",
p2,
hilite(filterPrintable(
std::string(contents, pos2, pos - pos2 + hash.size() + margin)),
pos - pos2, storePathHashLen,
getColour(hash))));
}
}
}
else if (st.type == FSAccessor::Type::tSymlink) {
auto target = accessor->readLink(p);
auto pos = target.find(dependencyPathHash);
if (pos != std::string::npos) {
std::cerr << fmt(" %s -> %s\n", p2, hilite(target, pos, storePathHashLen));
for (auto & hash : hashes) {
auto pos = target.find(hash);
if (pos != std::string::npos)
hits[hash].emplace_back(fmt("%s -> %s\n", p2,
hilite(target, pos, storePathHashLen, getColour(hash))));
}
}
};
recurse(path);
}
visitPath(node.path);
for (auto & ref : refs) {
auto hash = storePathToHash(ref.second->path);
bool last = all ? ref == *refs.rbegin() : true;
for (auto & hit : hits[hash]) {
bool first = hit == *hits[hash].begin();
std::cerr << tailPad
<< (first ? (last ? treeLast : treeConn) : (last ? treeNull : treeLine))
<< hit;
if (!all) break;
}
printNode(*ref.second,
tailPad + (last ? treeNull : treeLine),
tailPad + (last ? treeNull : treeLine));
}
};
try {
printNode(graph.at(packagePath), "", "");
} catch (BailOut & ) { }
}
};