From b7f0f65c1934851b038826b2ab78c0378a36143a Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Thu, 26 Apr 2007 14:20:31 +0000
Subject: [PATCH] =?UTF-8?q?*=20nix-env=20-q=20now=20has=20a=20flag=20--pre?=
 =?UTF-8?q?built-only=20(-b<)=20that=20causes=20nix-env=20=20=20to=20show?=
 =?UTF-8?q?=20only=20those=20derivations=20whose=20output=20is=20already?=
 =?UTF-8?q?=20in=20the=20Nix=20=20=20store=20or=20that=20can=20be=20substi?=
 =?UTF-8?q?tuted=20(i.e.,=20downloaded=20from=20somewhere).=20=20=20In=20o?=
 =?UTF-8?q?ther=20words,=20it=20shows=20the=20packages=20that=20can=20be?=
 =?UTF-8?q?=20installed=20=E2=80=9Cquickly=E2=80=9D,=20=20=20i.e.,=20don?=
 =?UTF-8?q?=E2=80=99t=20need=20to=20be=20built=20from=20source.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 doc/manual/release-notes.xml |  9 +++++++++
 src/nix-env/help.txt         | 14 ++++++++------
 src/nix-env/nix-env.cc       |  8 ++++++++
 3 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/doc/manual/release-notes.xml b/doc/manual/release-notes.xml
index 4830b323ef..e5d0adf74b 100644
--- a/doc/manual/release-notes.xml
+++ b/doc/manual/release-notes.xml
@@ -74,6 +74,15 @@
   <option>--set-flag</option>.</para></listitem>
   
 
+  <listitem><para><command>nix-env -q</command> now has a flag
+  <option>--prebuilt-only</option> (<option>-b</option>) that causes
+  <command>nix-env</command> to show only those derivations whose
+  output is already in the Nix store or that can be substituted (i.e.,
+  downloaded from somewhere).  In other words, it shows the packages
+  that can be installed “quickly”, i.e., don’t need to be built from
+  source.</para></listitem>
+  
+
   <listitem><para>TODO: new built-ins
   <function>builtins.attrNames</function>,
   <function>builtins.filterSource</function>,
diff --git a/src/nix-env/help.txt b/src/nix-env/help.txt
index 534d16ad3c..16e47a73e3 100644
--- a/src/nix-env/help.txt
+++ b/src/nix-env/help.txt
@@ -45,7 +45,12 @@ Upgrade flags:
   --eq: "upgrade" if the current version is equal
   --always: upgrade regardless of current version
 
-Query types:
+Query sources:
+
+  --installed: use installed derivations (default)
+  --available / -a: use derivations available in Nix expression
+
+Query flags:
 
   --status / -s: print installed/present status
   --no-name: hide derivation names
@@ -55,11 +60,8 @@ Query types:
   --compare-versions / -c: compare version to available or installed
   --drv-path: print path of derivation
   --out-path: print path of derivation output
-
-Query sources:
-
-  --installed: use installed derivations (default)
-  --available / -a: use derivations available in Nix expression
+  --prebuilt-only: only show derivations whose prebuilt binaries are
+      available on this machine or are downloadable
 
 Options:
 
diff --git a/src/nix-env/nix-env.cc b/src/nix-env/nix-env.cc
index 5dab2e60b2..77b7881711 100644
--- a/src/nix-env/nix-env.cc
+++ b/src/nix-env/nix-env.cc
@@ -831,6 +831,7 @@ static void opQuery(Globals & globals,
     bool printDrvPath = false;
     bool printOutPath = false;
     bool printDescription = false;
+    bool prebuiltOnly = false;
     bool compareVersions = false;
     bool xmlOutput = false;
 
@@ -849,6 +850,7 @@ static void opQuery(Globals & globals,
         else if (*i == "--out-path") printOutPath = true;
         else if (*i == "--installed") source = sInstalled;
         else if (*i == "--available" || *i == "-a") source = sAvailable;
+        else if (*i == "--prebuilt-only" || *i == "-b") prebuiltOnly = true;
         else if (*i == "--xml") xmlOutput = true;
         else throw UsageError(format("unknown flag `%1%'") % *i);
 
@@ -914,6 +916,12 @@ static void opQuery(Globals & globals,
 
             /* For XML output. */
             XMLAttrs attrs;
+
+            if (prebuiltOnly) {
+                if (!store->isValidPath(i->queryOutPath(globals.state)) &&
+                    !store->hasSubstitutes(i->queryOutPath(globals.state)))
+                    continue;
+            }
         
             if (printStatus) {
                 bool hasSubs = store->hasSubstitutes(i->queryOutPath(globals.state));