lix/src/nix-store/dotgraph.cc
Eelco Dolstra bbe97dff8b Make the Store API more type-safe
Most functions now take a StorePath argument rather than a Path (which
is just an alias for std::string). The StorePath constructor ensures
that the path is syntactically correct (i.e. it looks like
<store-dir>/<base32-hash>-<name>). Similarly, functions like
buildPaths() now take a StorePathWithOutputs, rather than abusing Path
by adding a '!<outputs>' suffix.

Note that the StorePath type is implemented in Rust. This involves
some hackery to allow Rust values to be used directly in C++, via a
helper type whose destructor calls the Rust type's drop()
function. The main issue is the dynamic nature of C++ move semantics:
after we have moved a Rust value, we should not call the drop function
on the original value. So when we move a value, we set the original
value to bitwise zero, and the destructor only calls drop() if the
value is not bitwise zero. This should be sufficient for most types.

Also lots of minor cleanups to the C++ API to make it more modern
(e.g. using std::optional and std::string_view in some places).
2019-12-10 22:06:05 +01:00

145 lines
3.6 KiB
C++

#include "dotgraph.hh"
#include "util.hh"
#include "store-api.hh"
#include <iostream>
using std::cout;
namespace nix {
static string dotQuote(std::string_view s)
{
return "\"" + std::string(s) + "\"";
}
static string nextColour()
{
static int n = 0;
static string colours[] =
{ "black", "red", "green", "blue"
, "magenta", "burlywood" };
return colours[n++ % (sizeof(colours) / sizeof(string))];
}
static string makeEdge(const string & src, const string & dst)
{
format f = format("%1% -> %2% [color = %3%];\n")
% dotQuote(src) % dotQuote(dst) % dotQuote(nextColour());
return f.str();
}
static string makeNode(const string & id, std::string_view label,
const string & colour)
{
format f = format("%1% [label = %2%, shape = box, "
"style = filled, fillcolor = %3%];\n")
% dotQuote(id) % dotQuote(label) % dotQuote(colour);
return f.str();
}
#if 0
string pathLabel(const Path & nePath, const string & elemPath)
{
return (string) nePath + "-" + elemPath;
}
void printClosure(const Path & nePath, const StoreExpr & fs)
{
PathSet workList(fs.closure.roots);
PathSet doneSet;
for (PathSet::iterator i = workList.begin(); i != workList.end(); ++i) {
cout << makeEdge(pathLabel(nePath, *i), nePath);
}
while (!workList.empty()) {
Path path = *(workList.begin());
workList.erase(path);
if (doneSet.insert(path).second) {
ClosureElems::const_iterator elem = fs.closure.elems.find(path);
if (elem == fs.closure.elems.end())
throw Error(format("bad closure, missing path '%1%'") % path);
for (StringSet::const_iterator i = elem->second.refs.begin();
i != elem->second.refs.end(); ++i)
{
workList.insert(*i);
cout << makeEdge(pathLabel(nePath, *i), pathLabel(nePath, path));
}
cout << makeNode(pathLabel(nePath, path),
symbolicName(path), "#ff0000");
}
}
}
#endif
void printDotGraph(ref<Store> store, StorePathSet && roots)
{
StorePathSet workList(std::move(roots));
StorePathSet doneSet;
cout << "digraph G {\n";
while (!workList.empty()) {
auto path = std::move(workList.extract(workList.begin()).value());
if (!doneSet.insert(path.clone()).second) continue;
cout << makeNode(std::string(path.to_string()), path.name(), "#ff0000");
for (auto & p : store->queryPathInfo(path)->references) {
if (p != path) {
workList.insert(p.clone());
cout << makeEdge(std::string(p.to_string()), std::string(p.to_string()));
}
}
#if 0
StoreExpr ne = storeExprFromPath(path);
string label, colour;
if (ne.type == StoreExpr::neDerivation) {
for (PathSet::iterator i = ne.derivation.inputs.begin();
i != ne.derivation.inputs.end(); ++i)
{
workList.insert(*i);
cout << makeEdge(*i, path);
}
label = "derivation";
colour = "#00ff00";
for (StringPairs::iterator i = ne.derivation.env.begin();
i != ne.derivation.env.end(); ++i)
if (i->first == "name") label = i->second;
}
else if (ne.type == StoreExpr::neClosure) {
label = "<closure>";
colour = "#00ffff";
printClosure(path, ne);
}
else abort();
cout << makeNode(path, label, colour);
#endif
}
cout << "}\n";
}
}