From 37d1b1cafd17a18dc7dbef3b4ba7fb204158d58b Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Fri, 10 Mar 2006 16:20:42 +0000
Subject: * `nix-env -qa --description' shows human-readable descriptions of  
 packages (provided that they have a `meta.description' attribute).   E.g.,

  $ ./src/nix-env/nix-env -qa --description gcc
  gcc-4.0.2   GNU Compiler Collection, 4.0.x (cross-compiler for sparc-linux)
  gcc-4.0.2   GNU Compiler Collection, 4.0.x (cross-compiler for mips-linux)
  gcc-4.0.2   GNU Compiler Collection, 4.0.x (cross-compiler for arm-linux)
  gcc-4.0.2   GNU Compiler Collection, 4.0.x
---
 src/libexpr/get-drvs.cc | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

(limited to 'src/libexpr/get-drvs.cc')

diff --git a/src/libexpr/get-drvs.cc b/src/libexpr/get-drvs.cc
index 63e68eb6f489..ff38ff794812 100644
--- a/src/libexpr/get-drvs.cc
+++ b/src/libexpr/get-drvs.cc
@@ -2,6 +2,49 @@
 #include "nixexpr-ast.hh"
 
 
+string DrvInfo::queryDrvPath(EvalState & state) const
+{
+    if (drvPath == "") {
+        Expr a = attrs.get("drvPath");
+        (string &) drvPath = a ? evalPath(state, a) : "";
+    }
+    return drvPath;
+}
+
+
+string DrvInfo::queryOutPath(EvalState & state) const
+{
+    if (outPath == "") {
+        Expr a = attrs.get("outPath");
+        if (!a) throw Error("output path missing");
+        (string &) outPath = evalPath(state, a);
+    }
+    return outPath;
+}
+
+
+MetaInfo DrvInfo::queryMetaInfo(EvalState & state) const
+{
+    MetaInfo meta;
+    
+    Expr a = attrs.get("meta");
+    if (!a) return meta; /* fine, empty meta information */
+
+    ATermMap attrs2;
+    queryAllAttrs(evalExpr(state, a), attrs2);
+
+    for (ATermIterator i(attrs2.keys()); i; ++i) {
+        ATerm s = coerceToString(evalExpr(state, attrs2.get(*i)));
+        if (s)
+            meta[aterm2String(*i)] = aterm2String(s);
+        /* For future compatibility, ignore attribute values that are
+           not strings. */
+    }
+
+    return meta;
+}
+
+
 typedef set<Expr> Exprs;
 
 
-- 
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