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Merge pull request #8763 from hercules-ci/backport-7447-to-2.13-maintenance

Backport 7447 to 2.13 maintenance
This commit is contained in:
Eelco Dolstra 2023-08-07 19:30:27 +02:00 committed by GitHub
commit 5bc21dccc9
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8 changed files with 76 additions and 10 deletions

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@ -38,3 +38,12 @@
* You can now disable the global flake registry by setting the `flake-registry`
configuration option to an empty string. The same can be achieved at runtime with
`--flake-registry ""`.
* Since 2.13.5, a new function `builtins.readFileType` is available. It is similar to
`builtins.readDir` but acts on a single file or directory.
* Since 2.13.5, the `builtins.readDir` function has been optimized when encountering not-yet-known
file types from POSIX's `readdir`. In such cases the type of each file was
discovered by making multiple syscalls. This change makes these operations
lazy such that these lookups will only be performed if the attribute is used.
This optimization affects a minority of filesystems and operating systems.

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@ -1,2 +0,0 @@
# Release X.Y (202?-??-??)

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@ -1646,23 +1646,73 @@ static RegisterPrimOp primop_hashFile({
.fun = prim_hashFile,
});
/* Stringize a directory entry enum. Used by `readFileType' and `readDir'. */
static const char * dirEntTypeToString(unsigned char dtType)
{
/* Enum DT_(DIR|LNK|REG|UNKNOWN) */
switch(dtType) {
case DT_REG: return "regular"; break;
case DT_DIR: return "directory"; break;
case DT_LNK: return "symlink"; break;
default: return "unknown"; break;
}
return "unknown"; /* Unreachable */
}
static void prim_readFileType(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
auto path = realisePath(state, pos, *args[0]);
/* Retrieve the directory entry type and stringize it. */
v.mkString(dirEntTypeToString(getFileType(path)));
}
static RegisterPrimOp primop_readFileType({
.name = "__readFileType",
.args = {"p"},
.doc = R"(
Determine the directory entry type of a filesystem node, being
one of "directory", "regular", "symlink", or "unknown".
)",
.fun = prim_readFileType,
});
/* Read a directory (without . or ..) */
static void prim_readDir(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
auto path = realisePath(state, pos, *args[0]);
// Retrieve directory entries for all nodes in a directory.
// This is similar to `getFileType` but is optimized to reduce system calls
// on many systems.
DirEntries entries = readDirectory(path);
auto attrs = state.buildBindings(entries.size());
// If we hit unknown directory entry types we may need to fallback to
// using `getFileType` on some systems.
// In order to reduce system calls we make each lookup lazy by using
// `builtins.readFileType` application.
Value * readFileType = nullptr;
for (auto & ent : entries) {
if (ent.type == DT_UNKNOWN)
ent.type = getFileType(path + "/" + ent.name);
attrs.alloc(ent.name).mkString(
ent.type == DT_REG ? "regular" :
ent.type == DT_DIR ? "directory" :
ent.type == DT_LNK ? "symlink" :
"unknown");
auto & attr = attrs.alloc(ent.name);
if (ent.type == DT_UNKNOWN) {
// Some filesystems or operating systems may not be able to return
// detailed node info quickly in this case we produce a thunk to
// query the file type lazily.
auto epath = state.allocValue();
Path path2 = path + "/" + ent.name;
epath->mkString(path2);
if (!readFileType)
readFileType = &state.getBuiltin("readFileType");
attr.mkApp(readFileType, epath);
} else {
// This branch of the conditional is much more likely.
// Here we just stringize the directory entry type.
attr.mkString(dirEntTypeToString(ent.type));
}
}
v.mkAttrs(attrs);

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@ -1 +1 @@
{ bar = "regular"; foo = "directory"; }
{ bar = "regular"; foo = "directory"; ldir = "symlink"; linked = "symlink"; }

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@ -0,0 +1 @@
{ bar = "regular"; foo = "directory"; ldir = "symlink"; linked = "symlink"; }

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@ -0,0 +1,6 @@
{
bar = builtins.readFileType ./readDir/bar;
foo = builtins.readFileType ./readDir/foo;
linked = builtins.readFileType ./readDir/linked;
ldir = builtins.readFileType ./readDir/ldir;
}

1
tests/lang/readDir/ldir Symbolic link
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@ -0,0 +1 @@
foo

1
tests/lang/readDir/linked Symbolic link
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@ -0,0 +1 @@
foo/git-hates-directories