Add 'third_party/nix/' from commit 'be66c7a6b24e3c3c6157fd37b86c7203d14acf10' r/724

git-subtree-dir: third_party/nix
git-subtree-mainline: cf8cd640c1adf74a3706efbcb0ea4625da106fb2
git-subtree-split: be66c7a6b24e3c3c6157fd37b86c7203d14acf10

1 files changed, 248 insertions, 0 deletions

diff --git a/third_party/nix/src/nix-channel/nix-channel.cc b/third_party/nix/src/nix-channel/nix-channel.cc
new file mode 100755
index 000000000000..70aa5c96669d
--- /dev/null
+++ b/third_party/nix/src/nix-channel/nix-channel.cc
@@ -0,0 +1,248 @@
+#include "shared.hh"
+#include "globals.hh"
+#include "download.hh"
+#include "store-api.hh"
+#include "legacy.hh"
+
+#include <fcntl.h>
+#include <regex>
+#include <pwd.h>
+
+using namespace nix;
+
+typedef std::map<string,string> Channels;
+
+static Channels channels;
+static Path channelsList;
+
+// Reads the list of channels.
+static void readChannels()
+{
+    if (!pathExists(channelsList)) return;
+    auto channelsFile = readFile(channelsList);
+
+    for (const auto & line : tokenizeString<std::vector<string>>(channelsFile, "\n")) {
+        chomp(line);
+        if (std::regex_search(line, std::regex("^\\s*\\#")))
+            continue;
+        auto split = tokenizeString<std::vector<string>>(line, " ");
+        auto url = std::regex_replace(split[0], std::regex("/*$"), "");
+        auto name = split.size() > 1 ? split[1] : baseNameOf(url);
+        channels[name] = url;
+    }
+}
+
+// Writes the list of channels.
+static void writeChannels()
+{
+    auto channelsFD = AutoCloseFD{open(channelsList.c_str(), O_WRONLY | O_CLOEXEC | O_CREAT | O_TRUNC, 0644)};
+    if (!channelsFD)
+        throw SysError(format("opening '%1%' for writing") % channelsList);
+    for (const auto & channel : channels)
+        writeFull(channelsFD.get(), channel.second + " " + channel.first + "\n");
+}
+
+// Adds a channel.
+static void addChannel(const string & url, const string & name)
+{
+    if (!regex_search(url, std::regex("^(file|http|https)://")))
+        throw Error(format("invalid channel URL '%1%'") % url);
+    if (!regex_search(name, std::regex("^[a-zA-Z0-9_][a-zA-Z0-9_\\.-]*$")))
+        throw Error(format("invalid channel identifier '%1%'") % name);
+    readChannels();
+    channels[name] = url;
+    writeChannels();
+}
+
+static Path profile;
+
+// Remove a channel.
+static void removeChannel(const string & name)
+{
+    readChannels();
+    channels.erase(name);
+    writeChannels();
+
+    runProgram(settings.nixBinDir + "/nix-env", true, { "--profile", profile, "--uninstall", name });
+}
+
+static Path nixDefExpr;
+
+// Fetch Nix expressions and binary cache URLs from the subscribed channels.
+static void update(const StringSet & channelNames)
+{
+    readChannels();
+
+    auto store = openStore();
+
+    // Download each channel.
+    Strings exprs;
+    for (const auto & channel : channels) {
+        auto name = channel.first;
+        auto url = channel.second;
+        if (!(channelNames.empty() || channelNames.count(name)))
+            continue;
+
+        // We want to download the url to a file to see if it's a tarball while also checking if we
+        // got redirected in the process, so that we can grab the various parts of a nix channel
+        // definition from a consistent location if the redirect changes mid-download.
+        CachedDownloadRequest request(url);
+        request.ttl = 0;
+        auto dl = getDownloader();
+        auto result = dl->downloadCached(store, request);
+        auto filename = result.path;
+        url = chomp(result.effectiveUri);
+
+        // If the URL contains a version number, append it to the name
+        // attribute (so that "nix-env -q" on the channels profile
+        // shows something useful).
+        auto cname = name;
+        std::smatch match;
+        auto urlBase = baseNameOf(url);
+        if (std::regex_search(urlBase, match, std::regex("(-\\d.*)$"))) {
+            cname = cname + (string) match[1];
+        }
+
+        std::string extraAttrs;
+
+        bool unpacked = false;
+        if (std::regex_search(filename, std::regex("\\.tar\\.(gz|bz2|xz)$"))) {
+            runProgram(settings.nixBinDir + "/nix-build", false, { "--no-out-link", "--expr", "import <nix/unpack-channel.nix> "
+                        "{ name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; }" });
+            unpacked = true;
+        }
+
+        if (!unpacked) {
+            // Download the channel tarball.
+            try {
+                filename = dl->downloadCached(store, CachedDownloadRequest(url + "/nixexprs.tar.xz")).path;
+            } catch (DownloadError & e) {
+                filename = dl->downloadCached(store, CachedDownloadRequest(url + "/nixexprs.tar.bz2")).path;
+            }
+            chomp(filename);
+        }
+
+        // Regardless of where it came from, add the expression representing this channel to accumulated expression
+        exprs.push_back("f: f { name = \"" + cname + "\"; channelName = \"" + name + "\"; src = builtins.storePath \"" + filename + "\"; " + extraAttrs + " }");
+    }
+
+    // Unpack the channel tarballs into the Nix store and install them
+    // into the channels profile.
+    std::cerr << "unpacking channels...\n";
+    Strings envArgs{ "--profile", profile, "--file", "<nix/unpack-channel.nix>", "--install", "--from-expression" };
+    for (auto & expr : exprs)
+        envArgs.push_back(std::move(expr));
+    envArgs.push_back("--quiet");
+    runProgram(settings.nixBinDir + "/nix-env", false, envArgs);
+
+    // Make the channels appear in nix-env.
+    struct stat st;
+    if (lstat(nixDefExpr.c_str(), &st) == 0) {
+        if (S_ISLNK(st.st_mode))
+            // old-skool ~/.nix-defexpr
+            if (unlink(nixDefExpr.c_str()) == -1)
+                throw SysError(format("unlinking %1%") % nixDefExpr);
+    } else if (errno != ENOENT) {
+        throw SysError(format("getting status of %1%") % nixDefExpr);
+    }
+    createDirs(nixDefExpr);
+    auto channelLink = nixDefExpr + "/channels";
+    replaceSymlink(profile, channelLink);
+}
+
+static int _main(int argc, char ** argv)
+{
+    {
+        // Figure out the name of the `.nix-channels' file to use
+        auto home = getHome();
+        channelsList = home + "/.nix-channels";
+        nixDefExpr = home + "/.nix-defexpr";
+
+        // Figure out the name of the channels profile.
+        profile = fmt("%s/profiles/per-user/%s/channels", settings.nixStateDir, getUserName());
+
+        enum {
+            cNone,
+            cAdd,
+            cRemove,
+            cList,
+            cUpdate,
+            cRollback
+        } cmd = cNone;
+        std::vector<string> args;
+        parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
+            if (*arg == "--help") {
+                showManPage("nix-channel");
+            } else if (*arg == "--version") {
+                printVersion("nix-channel");
+            } else if (*arg == "--add") {
+                cmd = cAdd;
+            } else if (*arg == "--remove") {
+                cmd = cRemove;
+            } else if (*arg == "--list") {
+                cmd = cList;
+            } else if (*arg == "--update") {
+                cmd = cUpdate;
+            } else if (*arg == "--rollback") {
+                cmd = cRollback;
+            } else {
+                args.push_back(std::move(*arg));
+            }
+            return true;
+        });
+
+        initPlugins();
+
+        switch (cmd) {
+            case cNone:
+                throw UsageError("no command specified");
+            case cAdd:
+                if (args.size() < 1 || args.size() > 2)
+                    throw UsageError("'--add' requires one or two arguments");
+                {
+                auto url = args[0];
+                std::string name;
+                if (args.size() == 2) {
+                    name = args[1];
+                } else {
+                    name = baseNameOf(url);
+                    name = std::regex_replace(name, std::regex("-unstable$"), "");
+                    name = std::regex_replace(name, std::regex("-stable$"), "");
+                }
+                addChannel(url, name);
+                }
+                break;
+            case cRemove:
+                if (args.size() != 1)
+                    throw UsageError("'--remove' requires one argument");
+                removeChannel(args[0]);
+                break;
+            case cList:
+                if (!args.empty())
+                    throw UsageError("'--list' expects no arguments");
+                readChannels();
+                for (const auto & channel : channels)
+                    std::cout << channel.first << ' ' << channel.second << '\n';
+                break;
+            case cUpdate:
+                update(StringSet(args.begin(), args.end()));
+                break;
+            case cRollback:
+                if (args.size() > 1)
+                    throw UsageError("'--rollback' has at most one argument");
+                Strings envArgs{"--profile", profile};
+                if (args.size() == 1) {
+                    envArgs.push_back("--switch-generation");
+                    envArgs.push_back(args[0]);
+                } else {
+                    envArgs.push_back("--rollback");
+                }
+                runProgram(settings.nixBinDir + "/nix-env", false, envArgs);
+                break;
+        }
+
+        return 0;
+    }
+}
+
+static RegisterLegacyCommand s1("nix-channel", _main);