nix-env -q --out-path: Support multiple outputs

We now print all output paths of a package, e.g.

  openssl-1.0.0i  bin=/nix/store/gq2mvh0wb9l90djvsagln3aqywqmr6vl-openssl-1.0.0i-bin;man=/nix/store/7zwf5r5hsdarl3n86dasvb4chm2xzw9n-openssl-1.0.0i-man;/nix/store/cj7xvk7fjp9q887359j75pw3pzjfmqf1-openssl-1.0.0i

or (in XML mode)

  <item attrPath="openssl" name="openssl-1.0.0i" system="x86_64-linux">
    <output name="bin" path="/nix/store/gq2mvh0wb9l90djvsagln3aqywqmr6vl-openssl-1.0.0i-bin" />
    <output name="man" path="/nix/store/7zwf5r5hsdarl3n86dasvb4chm2xzw9n-openssl-1.0.0i-man" />
    <output name="out" path="/nix/store/cj7xvk7fjp9q887359j75pw3pzjfmqf1-openssl-1.0.0i" />
  </item>

src/libexpr/eval.cc

@@ -138,6 +138,7 @@ EvalState::EvalState()
     , sName(symbols.create("name"))
     , sSystem(symbols.create("system"))
     , sOverrides(symbols.create("__overrides"))
+    , sOutputs(symbols.create("outputs"))
     , sOutputName(symbols.create("outputName"))
     , sIgnoreNulls(symbols.create("__ignoreNulls"))
     , baseEnv(allocEnv(128))

src/libexpr/eval.hh

@@ -93,7 +93,7 @@ public:
     SymbolTable symbols;
 
     const Symbol sWith, sOutPath, sDrvPath, sType, sMeta, sName,
-        sSystem, sOverrides, sOutputName, sIgnoreNulls;
+        sSystem, sOverrides, sOutputs, sOutputName, sIgnoreNulls;
 
     /* If set, force copying files to the Nix store even if they
        already exist there. */

src/libexpr/get-drvs.cc

@@ -28,12 +28,42 @@ string DrvInfo::queryOutPath(EvalState & state) const
 }
 
 
+DrvInfo::Outputs DrvInfo::queryOutputs(EvalState & state)
+{
+    if (outputs.empty()) {
+        /* Get the ‘outputs’ list. */
+        Bindings::iterator i = attrs->find(state.sOutputs);
+
+        if (i == attrs->end())
+            outputs["out"] = queryOutPath(state);
+        else {
+            state.forceList(*i->value);
+
+            /* For each output... */
+            for (unsigned int j = 0; j < i->value->list.length; ++j) {
+                /* Evaluate the corresponding attribute set. */
+                string name = state.forceStringNoCtx(*i->value->list.elems[j]);
+                Bindings::iterator out = attrs->find(state.symbols.create(name));
+                if (out == attrs->end()) continue; // FIXME: throw error?
+                state.forceAttrs(*out->value);
+
+                /* And evaluate its ‘outPath’ attribute. */
+                Bindings::iterator outPath = out->value->attrs->find(state.sOutPath);
+                if (outPath == out->value->attrs->end()) continue; // FIXME: throw error?
+                PathSet context;
+                outputs[name] = state.coerceToPath(*outPath->value, context);
+            }
+        }
+    }
+    return outputs;
+}
+
+
 string DrvInfo::queryOutputName(EvalState & state) const
 {
     if (outputName == "" && attrs) {
         Bindings::iterator i = attrs->find(state.sOutputName);
-        PathSet context;
+        (string &) outputName = i != attrs->end() ? state.forceStringNoCtx(*i->value) : "";
-        (string &) outputName = i != attrs->end() ? state.coerceToString(*i->value, context) : "";
     }
     return outputName;
 }

src/libexpr/get-drvs.hh

@@ -25,10 +25,14 @@ typedef std::map<string, MetaValue> MetaInfo;
 
 struct DrvInfo
 {
+public:
+    typedef std::map<string, Path> Outputs;
+
 private:
     string drvPath;
     string outPath;
     string outputName;
+    Outputs outputs;
 
     bool metaInfoRead;
     MetaInfo meta;
@@ -48,6 +52,7 @@ public:
     string queryDrvPath(EvalState & state) const;
     string queryOutPath(EvalState & state) const;
     string queryOutputName(EvalState & state) const;
+    Outputs queryOutputs(EvalState & state);
     MetaInfo queryMetaInfo(EvalState & state) const;
     MetaValue queryMetaInfo(EvalState & state, const string & name) const;
 

src/nix-env/nix-env.cc

@@ -1041,12 +1041,15 @@ static void opQuery(Globals & globals,
                     columns.push_back(drvPath == "" ? "-" : drvPath);
             }
 
-            if (printOutPath) {
+            if (printOutPath && !xmlOutput) {
-                string outPath = i->queryOutPath(globals.state);
+                DrvInfo::Outputs outputs = i->queryOutputs(globals.state);
-                if (xmlOutput) {
+                string s;
-                    if (outPath != "") attrs["outPath"] = outPath;
+                foreach (DrvInfo::Outputs::iterator, j, outputs) {
-                } else
+                    if (!s.empty()) s += ';';
-                    columns.push_back(outPath);
+                    if (j->first != "out") { s += j->first; s += "="; }
+                    s += j->second;
+                }
+                columns.push_back(s);
             }
 
             if (printDescription) {
@@ -1059,9 +1062,19 @@ static void opQuery(Globals & globals,
                     columns.push_back(descr);
             }
 
-            if (xmlOutput)
+            if (xmlOutput) {
-                if (printMeta) {
+                if (printOutPath || printMeta) {
                     XMLOpenElement item(xml, "item", attrs);
+                    if (printOutPath) {
+                        DrvInfo::Outputs outputs = i->queryOutputs(globals.state);
+                        foreach (DrvInfo::Outputs::iterator, j, outputs) {
+                            XMLAttrs attrs2;
+                            attrs2["name"] = j->first;
+                            attrs2["path"] = j->second;
+                            xml.writeEmptyElement("output", attrs2);
+                        }
+                    }
+                    if (printMeta) {
                         MetaInfo meta = i->queryMetaInfo(globals.state);
                         for (MetaInfo::iterator j = meta.begin(); j != meta.end(); ++j) {
                             XMLAttrs attrs2;
@@ -1085,9 +1098,9 @@ static void opQuery(Globals & globals,
                             }
                         }
                     }
-                else
+                } else
                     xml.writeEmptyElement("item", attrs);
-            else
+            } else
                 table.push_back(columns);
 
             cout.flush();