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authorEelco Dolstra <eelco.dolstra@logicblox.com>2016-04-29T18·14+0200
committerEelco Dolstra <eelco.dolstra@logicblox.com>2016-04-29T18·47+0200
commit38539b943a060d9cdfc24d6e5d997c0885b8aa2f (patch)
tree3f17e49cd6f969dec78befab26e7c68ce3c05956
parent83258225e6be25cd706df0f96dcbd4b04c352056 (diff)
Add fetchgit builtin
The function builtins.fetchgit fetches Git repositories at evaluation
time, similar to builtins.fetchTarball. (Perhaps the name should be
changed, being confusing with respect to Nixpkgs's fetchgit function,
with works at build time.)

Example:

  (import (builtins.fetchgit git://github.com/NixOS/nixpkgs) {}).hello

or

  (import (builtins.fetchgit {
    url = git://github.com/NixOS/nixpkgs-channels;
    rev = "nixos-16.03";
  }) {}).hello

Note that the result does not contain a .git directory.
-rw-r--r--src/libexpr/primops/fetchgit.cc77
-rw-r--r--src/libstore/download.cc2
2 files changed, 78 insertions, 1 deletions
diff --git a/src/libexpr/primops/fetchgit.cc b/src/libexpr/primops/fetchgit.cc
new file mode 100644
index 000000000000..e2a545ee0562
--- /dev/null
+++ b/src/libexpr/primops/fetchgit.cc
@@ -0,0 +1,77 @@
+#include "primops.hh"
+#include "eval-inline.hh"
+#include "download.hh"
+#include "store-api.hh"
+
+namespace nix {
+
+static void prim_fetchgit(EvalState & state, const Pos & pos, Value * * args, Value & v)
+{
+    // FIXME: cut&paste from fetch().
+    if (state.restricted) throw Error("‘fetchgit’ is not allowed in restricted mode");
+
+    std::string url;
+    std::string rev = "master";
+
+    state.forceValue(*args[0]);
+
+    if (args[0]->type == tAttrs) {
+
+        state.forceAttrs(*args[0], pos);
+
+        for (auto & attr : *args[0]->attrs) {
+            string name(attr.name);
+            if (name == "url")
+                url = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else if (name == "rev")
+                rev = state.forceStringNoCtx(*attr.value, *attr.pos);
+            else
+                throw EvalError(format("unsupported argument ‘%1%’ to ‘fetchgit’, at %3%") % attr.name % attr.pos);
+        }
+
+        if (url.empty())
+            throw EvalError(format("‘url’ argument required, at %1%") % pos);
+
+    } else
+        url = state.forceStringNoCtx(*args[0], pos);
+
+    if (!isUri(url))
+        throw EvalError(format("‘%s’ is not a valid URI, at %s") % url % pos);
+
+    Path cacheDir = getCacheDir() + "/nix/git";
+
+    if (!pathExists(cacheDir)) {
+        createDirs(cacheDir);
+        runProgram("git", true, { "init", "--bare", cacheDir });
+    }
+
+    Activity act(*logger, lvlInfo, format("fetching Git repository ‘%s’") % url);
+
+    std::string localRef = "pid-" + std::to_string(getpid());
+    Path localRefFile = cacheDir + "/refs/heads/" + localRef;
+
+    runProgram("git", true, { "-C", cacheDir, "fetch", url, rev + ":" + localRef });
+
+    std::string commitHash = chomp(readFile(localRefFile));
+
+    unlink(localRefFile.c_str());
+
+    debug(format("got revision ‘%s’") % commitHash);
+
+    // FIXME: should pipe this, or find some better way to extract a
+    // revision.
+    auto tar = runProgram("git", true, { "-C", cacheDir, "archive", commitHash });
+
+    Path tmpDir = createTempDir();
+    AutoDelete delTmpDir(tmpDir, true);
+
+    runProgram("tar", true, { "x", "-C", tmpDir }, tar);
+
+    Path storePath = state.store->addToStore("git-export", tmpDir);
+
+    mkString(v, storePath, PathSet({storePath}));
+}
+
+static RegisterPrimOp r("__fetchgit", 1, prim_fetchgit);
+
+}
diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index eed630517d11..6e39330e40d9 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -313,7 +313,7 @@ bool isUri(const string & s)
     size_t pos = s.find("://");
     if (pos == string::npos) return false;
     string scheme(s, 0, pos);
-    return scheme == "http" || scheme == "https" || scheme == "file" || scheme == "channel";
+    return scheme == "http" || scheme == "https" || scheme == "file" || scheme == "channel" || scheme == "git";
 }