948 lines
35 KiB
C++
948 lines
35 KiB
C++
#include "download.hh"
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#include "util.hh"
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#include "globals.hh"
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#include "hash.hh"
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#include "store-api.hh"
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#include "archive.hh"
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#include "s3.hh"
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#include "compression.hh"
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#include "pathlocks.hh"
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#include "finally.hh"
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#include "tarfile.hh"
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#ifdef ENABLE_S3
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#include <aws/core/client/ClientConfiguration.h>
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#endif
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#include <unistd.h>
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#include <fcntl.h>
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#include <curl/curl.h>
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#include <algorithm>
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#include <cmath>
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#include <cstring>
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#include <iostream>
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#include <queue>
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#include <random>
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#include <thread>
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using namespace std::string_literals;
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namespace nix {
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DownloadSettings downloadSettings;
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static GlobalConfig::Register r1(&downloadSettings);
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CachedDownloadRequest::CachedDownloadRequest(const std::string & uri)
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: uri(uri), ttl(settings.tarballTtl)
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{ }
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std::string resolveUri(const std::string & uri)
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{
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if (uri.compare(0, 8, "channel:") == 0)
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return "https://nixos.org/channels/" + std::string(uri, 8) + "/nixexprs.tar.xz";
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else
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return uri;
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}
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struct CurlDownloader : public Downloader
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{
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CURLM * curlm = 0;
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std::random_device rd;
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std::mt19937 mt19937;
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struct DownloadItem : public std::enable_shared_from_this<DownloadItem>
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{
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CurlDownloader & downloader;
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DownloadRequest request;
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DownloadResult result;
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Activity act;
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bool done = false; // whether either the success or failure function has been called
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Callback<DownloadResult> callback;
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CURL * req = 0;
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bool active = false; // whether the handle has been added to the multi object
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std::string status;
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unsigned int attempt = 0;
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/* Don't start this download until the specified time point
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has been reached. */
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std::chrono::steady_clock::time_point embargo;
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struct curl_slist * requestHeaders = 0;
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std::string encoding;
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bool acceptRanges = false;
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curl_off_t writtenToSink = 0;
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DownloadItem(CurlDownloader & downloader,
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const DownloadRequest & request,
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Callback<DownloadResult> && callback)
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: downloader(downloader)
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, request(request)
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, act(*logger, lvlTalkative, actDownload,
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fmt(request.data ? "uploading '%s'" : "downloading '%s'", request.uri),
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{request.uri}, request.parentAct)
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, callback(std::move(callback))
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, finalSink([this](const unsigned char * data, size_t len) {
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if (this->request.dataCallback) {
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writtenToSink += len;
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this->request.dataCallback((char *) data, len);
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} else
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this->result.data->append((char *) data, len);
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})
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{
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if (!request.expectedETag.empty())
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requestHeaders = curl_slist_append(requestHeaders, ("If-None-Match: " + request.expectedETag).c_str());
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if (!request.mimeType.empty())
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requestHeaders = curl_slist_append(requestHeaders, ("Content-Type: " + request.mimeType).c_str());
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}
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~DownloadItem()
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{
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if (req) {
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if (active)
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curl_multi_remove_handle(downloader.curlm, req);
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curl_easy_cleanup(req);
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}
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if (requestHeaders) curl_slist_free_all(requestHeaders);
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try {
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if (!done)
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fail(DownloadError(Interrupted, format("download of '%s' was interrupted") % request.uri));
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} catch (...) {
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ignoreException();
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}
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}
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void failEx(std::exception_ptr ex)
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{
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assert(!done);
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done = true;
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callback.rethrow(ex);
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}
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template<class T>
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void fail(const T & e)
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{
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failEx(std::make_exception_ptr(e));
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}
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LambdaSink finalSink;
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std::shared_ptr<CompressionSink> decompressionSink;
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std::exception_ptr writeException;
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size_t writeCallback(void * contents, size_t size, size_t nmemb)
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{
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try {
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size_t realSize = size * nmemb;
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result.bodySize += realSize;
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if (!decompressionSink)
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decompressionSink = makeDecompressionSink(encoding, finalSink);
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(*decompressionSink)((unsigned char *) contents, realSize);
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return realSize;
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} catch (...) {
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writeException = std::current_exception();
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return 0;
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}
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}
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static size_t writeCallbackWrapper(void * contents, size_t size, size_t nmemb, void * userp)
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{
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return ((DownloadItem *) userp)->writeCallback(contents, size, nmemb);
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}
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size_t headerCallback(void * contents, size_t size, size_t nmemb)
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{
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size_t realSize = size * nmemb;
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std::string line((char *) contents, realSize);
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printMsg(lvlVomit, format("got header for '%s': %s") % request.uri % trim(line));
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if (line.compare(0, 5, "HTTP/") == 0) { // new response starts
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result.etag = "";
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auto ss = tokenizeString<vector<string>>(line, " ");
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status = ss.size() >= 2 ? ss[1] : "";
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result.data = std::make_shared<std::string>();
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result.bodySize = 0;
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acceptRanges = false;
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encoding = "";
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} else {
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auto i = line.find(':');
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if (i != string::npos) {
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string name = toLower(trim(string(line, 0, i)));
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if (name == "etag") {
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result.etag = trim(string(line, i + 1));
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/* Hack to work around a GitHub bug: it sends
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ETags, but ignores If-None-Match. So if we get
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the expected ETag on a 200 response, then shut
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down the connection because we already have the
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data. */
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if (result.etag == request.expectedETag && status == "200") {
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debug(format("shutting down on 200 HTTP response with expected ETag"));
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return 0;
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}
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} else if (name == "content-encoding")
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encoding = trim(string(line, i + 1));
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else if (name == "accept-ranges" && toLower(trim(std::string(line, i + 1))) == "bytes")
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acceptRanges = true;
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}
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}
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return realSize;
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}
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static size_t headerCallbackWrapper(void * contents, size_t size, size_t nmemb, void * userp)
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{
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return ((DownloadItem *) userp)->headerCallback(contents, size, nmemb);
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}
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int progressCallback(double dltotal, double dlnow)
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{
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try {
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act.progress(dlnow, dltotal);
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} catch (nix::Interrupted &) {
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assert(_isInterrupted);
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}
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return _isInterrupted;
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}
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static int progressCallbackWrapper(void * userp, double dltotal, double dlnow, double ultotal, double ulnow)
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{
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return ((DownloadItem *) userp)->progressCallback(dltotal, dlnow);
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}
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static int debugCallback(CURL * handle, curl_infotype type, char * data, size_t size, void * userptr)
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{
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if (type == CURLINFO_TEXT)
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vomit("curl: %s", chomp(std::string(data, size)));
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return 0;
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}
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size_t readOffset = 0;
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size_t readCallback(char *buffer, size_t size, size_t nitems)
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{
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if (readOffset == request.data->length())
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return 0;
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auto count = std::min(size * nitems, request.data->length() - readOffset);
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assert(count);
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memcpy(buffer, request.data->data() + readOffset, count);
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readOffset += count;
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return count;
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}
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static size_t readCallbackWrapper(char *buffer, size_t size, size_t nitems, void * userp)
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{
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return ((DownloadItem *) userp)->readCallback(buffer, size, nitems);
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}
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void init()
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{
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if (!req) req = curl_easy_init();
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curl_easy_reset(req);
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if (verbosity >= lvlVomit) {
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curl_easy_setopt(req, CURLOPT_VERBOSE, 1);
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curl_easy_setopt(req, CURLOPT_DEBUGFUNCTION, DownloadItem::debugCallback);
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}
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curl_easy_setopt(req, CURLOPT_URL, request.uri.c_str());
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curl_easy_setopt(req, CURLOPT_FOLLOWLOCATION, 1L);
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curl_easy_setopt(req, CURLOPT_MAXREDIRS, 10);
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curl_easy_setopt(req, CURLOPT_NOSIGNAL, 1);
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curl_easy_setopt(req, CURLOPT_USERAGENT,
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("curl/" LIBCURL_VERSION " Nix/" + nixVersion +
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(downloadSettings.userAgentSuffix != "" ? " " + downloadSettings.userAgentSuffix.get() : "")).c_str());
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#if LIBCURL_VERSION_NUM >= 0x072b00
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curl_easy_setopt(req, CURLOPT_PIPEWAIT, 1);
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#endif
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#if LIBCURL_VERSION_NUM >= 0x072f00
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if (downloadSettings.enableHttp2)
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curl_easy_setopt(req, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_2TLS);
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else
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curl_easy_setopt(req, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
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#endif
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curl_easy_setopt(req, CURLOPT_WRITEFUNCTION, DownloadItem::writeCallbackWrapper);
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curl_easy_setopt(req, CURLOPT_WRITEDATA, this);
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curl_easy_setopt(req, CURLOPT_HEADERFUNCTION, DownloadItem::headerCallbackWrapper);
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curl_easy_setopt(req, CURLOPT_HEADERDATA, this);
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curl_easy_setopt(req, CURLOPT_PROGRESSFUNCTION, progressCallbackWrapper);
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curl_easy_setopt(req, CURLOPT_PROGRESSDATA, this);
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curl_easy_setopt(req, CURLOPT_NOPROGRESS, 0);
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curl_easy_setopt(req, CURLOPT_HTTPHEADER, requestHeaders);
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if (request.head)
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curl_easy_setopt(req, CURLOPT_NOBODY, 1);
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if (request.data) {
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curl_easy_setopt(req, CURLOPT_UPLOAD, 1L);
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curl_easy_setopt(req, CURLOPT_READFUNCTION, readCallbackWrapper);
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curl_easy_setopt(req, CURLOPT_READDATA, this);
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curl_easy_setopt(req, CURLOPT_INFILESIZE_LARGE, (curl_off_t) request.data->length());
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}
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if (request.verifyTLS) {
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debug("verify TLS: Nix CA file = '%s'", settings.caFile);
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if (settings.caFile != "")
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curl_easy_setopt(req, CURLOPT_CAINFO, settings.caFile.c_str());
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} else {
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curl_easy_setopt(req, CURLOPT_SSL_VERIFYPEER, 0);
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curl_easy_setopt(req, CURLOPT_SSL_VERIFYHOST, 0);
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}
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curl_easy_setopt(req, CURLOPT_CONNECTTIMEOUT, downloadSettings.connectTimeout.get());
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curl_easy_setopt(req, CURLOPT_LOW_SPEED_LIMIT, 1L);
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curl_easy_setopt(req, CURLOPT_LOW_SPEED_TIME, downloadSettings.stalledDownloadTimeout.get());
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/* If no file exist in the specified path, curl continues to work
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anyway as if netrc support was disabled. */
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curl_easy_setopt(req, CURLOPT_NETRC_FILE, settings.netrcFile.get().c_str());
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curl_easy_setopt(req, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
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if (writtenToSink)
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curl_easy_setopt(req, CURLOPT_RESUME_FROM_LARGE, writtenToSink);
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result.data = std::make_shared<std::string>();
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result.bodySize = 0;
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}
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void finish(CURLcode code)
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{
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long httpStatus = 0;
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curl_easy_getinfo(req, CURLINFO_RESPONSE_CODE, &httpStatus);
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char * effectiveUriCStr;
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curl_easy_getinfo(req, CURLINFO_EFFECTIVE_URL, &effectiveUriCStr);
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if (effectiveUriCStr)
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result.effectiveUri = effectiveUriCStr;
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debug("finished %s of '%s'; curl status = %d, HTTP status = %d, body = %d bytes",
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request.verb(), request.uri, code, httpStatus, result.bodySize);
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if (decompressionSink) {
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try {
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decompressionSink->finish();
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} catch (...) {
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writeException = std::current_exception();
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}
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}
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if (code == CURLE_WRITE_ERROR && result.etag == request.expectedETag) {
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code = CURLE_OK;
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httpStatus = 304;
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}
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if (writeException)
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failEx(writeException);
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else if (code == CURLE_OK &&
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(httpStatus == 200 || httpStatus == 201 || httpStatus == 204 || httpStatus == 206 || httpStatus == 304 || httpStatus == 226 /* FTP */ || httpStatus == 0 /* other protocol */))
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{
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result.cached = httpStatus == 304;
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act.progress(result.bodySize, result.bodySize);
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done = true;
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callback(std::move(result));
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}
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else {
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// We treat most errors as transient, but won't retry when hopeless
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Error err = Transient;
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if (httpStatus == 404 || httpStatus == 410 || code == CURLE_FILE_COULDNT_READ_FILE) {
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// The file is definitely not there
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err = NotFound;
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} else if (httpStatus == 401 || httpStatus == 403 || httpStatus == 407) {
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// Don't retry on authentication/authorization failures
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err = Forbidden;
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} else if (httpStatus >= 400 && httpStatus < 500 && httpStatus != 408) {
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// Most 4xx errors are client errors and are probably not worth retrying:
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// * 408 means the server timed out waiting for us, so we try again
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err = Misc;
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} else if (httpStatus == 501 || httpStatus == 505 || httpStatus == 511) {
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// Let's treat most 5xx (server) errors as transient, except for a handful:
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// * 501 not implemented
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// * 505 http version not supported
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// * 511 we're behind a captive portal
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err = Misc;
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} else {
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// Don't bother retrying on certain cURL errors either
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switch (code) {
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case CURLE_FAILED_INIT:
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case CURLE_URL_MALFORMAT:
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case CURLE_NOT_BUILT_IN:
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case CURLE_REMOTE_ACCESS_DENIED:
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case CURLE_FILE_COULDNT_READ_FILE:
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case CURLE_FUNCTION_NOT_FOUND:
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case CURLE_ABORTED_BY_CALLBACK:
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case CURLE_BAD_FUNCTION_ARGUMENT:
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case CURLE_INTERFACE_FAILED:
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case CURLE_UNKNOWN_OPTION:
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case CURLE_SSL_CACERT_BADFILE:
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case CURLE_TOO_MANY_REDIRECTS:
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case CURLE_WRITE_ERROR:
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err = Misc;
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break;
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default: // Shut up warnings
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break;
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}
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}
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attempt++;
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auto exc =
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code == CURLE_ABORTED_BY_CALLBACK && _isInterrupted
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? DownloadError(Interrupted, fmt("%s of '%s' was interrupted", request.verb(), request.uri))
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: httpStatus != 0
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? DownloadError(err,
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fmt("unable to %s '%s': HTTP error %d",
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request.verb(), request.uri, httpStatus)
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+ (code == CURLE_OK ? "" : fmt(" (curl error: %s)", curl_easy_strerror(code)))
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)
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: DownloadError(err,
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fmt("unable to %s '%s': %s (%d)",
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request.verb(), request.uri, curl_easy_strerror(code), code));
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/* If this is a transient error, then maybe retry the
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download after a while. If we're writing to a
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sink, we can only retry if the server supports
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ranged requests. */
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if (err == Transient
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&& attempt < request.tries
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&& (!this->request.dataCallback
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|| writtenToSink == 0
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|| (acceptRanges && encoding.empty())))
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{
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int ms = request.baseRetryTimeMs * std::pow(2.0f, attempt - 1 + std::uniform_real_distribution<>(0.0, 0.5)(downloader.mt19937));
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if (writtenToSink)
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warn("%s; retrying from offset %d in %d ms", exc.what(), writtenToSink, ms);
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else
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warn("%s; retrying in %d ms", exc.what(), ms);
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embargo = std::chrono::steady_clock::now() + std::chrono::milliseconds(ms);
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downloader.enqueueItem(shared_from_this());
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}
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else
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fail(exc);
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}
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}
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};
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struct State
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{
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struct EmbargoComparator {
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bool operator() (const std::shared_ptr<DownloadItem> & i1, const std::shared_ptr<DownloadItem> & i2) {
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return i1->embargo > i2->embargo;
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}
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};
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bool quit = false;
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std::priority_queue<std::shared_ptr<DownloadItem>, std::vector<std::shared_ptr<DownloadItem>>, EmbargoComparator> incoming;
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};
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Sync<State> state_;
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/* We can't use a std::condition_variable to wake up the curl
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thread, because it only monitors file descriptors. So use a
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pipe instead. */
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Pipe wakeupPipe;
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std::thread workerThread;
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CurlDownloader()
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: mt19937(rd())
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{
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static std::once_flag globalInit;
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std::call_once(globalInit, curl_global_init, CURL_GLOBAL_ALL);
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curlm = curl_multi_init();
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#if LIBCURL_VERSION_NUM >= 0x072b00 // Multiplex requires >= 7.43.0
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curl_multi_setopt(curlm, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
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#endif
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#if LIBCURL_VERSION_NUM >= 0x071e00 // Max connections requires >= 7.30.0
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curl_multi_setopt(curlm, CURLMOPT_MAX_TOTAL_CONNECTIONS,
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downloadSettings.httpConnections.get());
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#endif
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wakeupPipe.create();
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fcntl(wakeupPipe.readSide.get(), F_SETFL, O_NONBLOCK);
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workerThread = std::thread([&]() { workerThreadEntry(); });
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}
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~CurlDownloader()
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{
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stopWorkerThread();
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workerThread.join();
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if (curlm) curl_multi_cleanup(curlm);
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}
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void stopWorkerThread()
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{
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/* Signal the worker thread to exit. */
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{
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auto state(state_.lock());
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state->quit = true;
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}
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writeFull(wakeupPipe.writeSide.get(), " ", false);
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}
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void workerThreadMain()
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{
|
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/* Cause this thread to be notified on SIGINT. */
|
|
auto callback = createInterruptCallback([&]() {
|
|
stopWorkerThread();
|
|
});
|
|
|
|
std::map<CURL *, std::shared_ptr<DownloadItem>> items;
|
|
|
|
bool quit = false;
|
|
|
|
std::chrono::steady_clock::time_point nextWakeup;
|
|
|
|
while (!quit) {
|
|
checkInterrupt();
|
|
|
|
/* Let curl do its thing. */
|
|
int running;
|
|
CURLMcode mc = curl_multi_perform(curlm, &running);
|
|
if (mc != CURLM_OK)
|
|
throw nix::Error(format("unexpected error from curl_multi_perform(): %s") % curl_multi_strerror(mc));
|
|
|
|
/* Set the promises of any finished requests. */
|
|
CURLMsg * msg;
|
|
int left;
|
|
while ((msg = curl_multi_info_read(curlm, &left))) {
|
|
if (msg->msg == CURLMSG_DONE) {
|
|
auto i = items.find(msg->easy_handle);
|
|
assert(i != items.end());
|
|
i->second->finish(msg->data.result);
|
|
curl_multi_remove_handle(curlm, i->second->req);
|
|
i->second->active = false;
|
|
items.erase(i);
|
|
}
|
|
}
|
|
|
|
/* Wait for activity, including wakeup events. */
|
|
int numfds = 0;
|
|
struct curl_waitfd extraFDs[1];
|
|
extraFDs[0].fd = wakeupPipe.readSide.get();
|
|
extraFDs[0].events = CURL_WAIT_POLLIN;
|
|
extraFDs[0].revents = 0;
|
|
long maxSleepTimeMs = items.empty() ? 10000 : 100;
|
|
auto sleepTimeMs =
|
|
nextWakeup != std::chrono::steady_clock::time_point()
|
|
? std::max(0, (int) std::chrono::duration_cast<std::chrono::milliseconds>(nextWakeup - std::chrono::steady_clock::now()).count())
|
|
: maxSleepTimeMs;
|
|
vomit("download thread waiting for %d ms", sleepTimeMs);
|
|
mc = curl_multi_wait(curlm, extraFDs, 1, sleepTimeMs, &numfds);
|
|
if (mc != CURLM_OK)
|
|
throw nix::Error(format("unexpected error from curl_multi_wait(): %s") % curl_multi_strerror(mc));
|
|
|
|
nextWakeup = std::chrono::steady_clock::time_point();
|
|
|
|
/* Add new curl requests from the incoming requests queue,
|
|
except for requests that are embargoed (waiting for a
|
|
retry timeout to expire). */
|
|
if (extraFDs[0].revents & CURL_WAIT_POLLIN) {
|
|
char buf[1024];
|
|
auto res = read(extraFDs[0].fd, buf, sizeof(buf));
|
|
if (res == -1 && errno != EINTR)
|
|
throw SysError("reading curl wakeup socket");
|
|
}
|
|
|
|
std::vector<std::shared_ptr<DownloadItem>> incoming;
|
|
auto now = std::chrono::steady_clock::now();
|
|
|
|
{
|
|
auto state(state_.lock());
|
|
while (!state->incoming.empty()) {
|
|
auto item = state->incoming.top();
|
|
if (item->embargo <= now) {
|
|
incoming.push_back(item);
|
|
state->incoming.pop();
|
|
} else {
|
|
if (nextWakeup == std::chrono::steady_clock::time_point()
|
|
|| item->embargo < nextWakeup)
|
|
nextWakeup = item->embargo;
|
|
break;
|
|
}
|
|
}
|
|
quit = state->quit;
|
|
}
|
|
|
|
for (auto & item : incoming) {
|
|
debug("starting %s of %s", item->request.verb(), item->request.uri);
|
|
item->init();
|
|
curl_multi_add_handle(curlm, item->req);
|
|
item->active = true;
|
|
items[item->req] = item;
|
|
}
|
|
}
|
|
|
|
debug("download thread shutting down");
|
|
}
|
|
|
|
void workerThreadEntry()
|
|
{
|
|
try {
|
|
workerThreadMain();
|
|
} catch (nix::Interrupted & e) {
|
|
} catch (std::exception & e) {
|
|
printError("unexpected error in download thread: %s", e.what());
|
|
}
|
|
|
|
{
|
|
auto state(state_.lock());
|
|
while (!state->incoming.empty()) state->incoming.pop();
|
|
state->quit = true;
|
|
}
|
|
}
|
|
|
|
void enqueueItem(std::shared_ptr<DownloadItem> item)
|
|
{
|
|
if (item->request.data
|
|
&& !hasPrefix(item->request.uri, "http://")
|
|
&& !hasPrefix(item->request.uri, "https://"))
|
|
throw nix::Error("uploading to '%s' is not supported", item->request.uri);
|
|
|
|
{
|
|
auto state(state_.lock());
|
|
if (state->quit)
|
|
throw nix::Error("cannot enqueue download request because the download thread is shutting down");
|
|
state->incoming.push(item);
|
|
}
|
|
writeFull(wakeupPipe.writeSide.get(), " ");
|
|
}
|
|
|
|
#ifdef ENABLE_S3
|
|
std::tuple<std::string, std::string, Store::Params> parseS3Uri(std::string uri)
|
|
{
|
|
auto [path, params] = splitUriAndParams(uri);
|
|
|
|
auto slash = path.find('/', 5); // 5 is the length of "s3://" prefix
|
|
if (slash == std::string::npos)
|
|
throw nix::Error("bad S3 URI '%s'", path);
|
|
|
|
std::string bucketName(path, 5, slash - 5);
|
|
std::string key(path, slash + 1);
|
|
|
|
return {bucketName, key, params};
|
|
}
|
|
#endif
|
|
|
|
void enqueueDownload(const DownloadRequest & request,
|
|
Callback<DownloadResult> callback) override
|
|
{
|
|
/* Ugly hack to support s3:// URIs. */
|
|
if (hasPrefix(request.uri, "s3://")) {
|
|
// FIXME: do this on a worker thread
|
|
try {
|
|
#ifdef ENABLE_S3
|
|
auto [bucketName, key, params] = parseS3Uri(request.uri);
|
|
|
|
std::string profile = get(params, "profile").value_or("");
|
|
std::string region = get(params, "region").value_or(Aws::Region::US_EAST_1);
|
|
std::string scheme = get(params, "scheme").value_or("");
|
|
std::string endpoint = get(params, "endpoint").value_or("");
|
|
|
|
S3Helper s3Helper(profile, region, scheme, endpoint);
|
|
|
|
// FIXME: implement ETag
|
|
auto s3Res = s3Helper.getObject(bucketName, key);
|
|
DownloadResult res;
|
|
if (!s3Res.data)
|
|
throw DownloadError(NotFound, fmt("S3 object '%s' does not exist", request.uri));
|
|
res.data = s3Res.data;
|
|
callback(std::move(res));
|
|
#else
|
|
throw nix::Error("cannot download '%s' because Nix is not built with S3 support", request.uri);
|
|
#endif
|
|
} catch (...) { callback.rethrow(); }
|
|
return;
|
|
}
|
|
|
|
enqueueItem(std::make_shared<DownloadItem>(*this, request, std::move(callback)));
|
|
}
|
|
};
|
|
|
|
ref<Downloader> getDownloader()
|
|
{
|
|
static ref<Downloader> downloader = makeDownloader();
|
|
return downloader;
|
|
}
|
|
|
|
ref<Downloader> makeDownloader()
|
|
{
|
|
return make_ref<CurlDownloader>();
|
|
}
|
|
|
|
std::future<DownloadResult> Downloader::enqueueDownload(const DownloadRequest & request)
|
|
{
|
|
auto promise = std::make_shared<std::promise<DownloadResult>>();
|
|
enqueueDownload(request,
|
|
{[promise](std::future<DownloadResult> fut) {
|
|
try {
|
|
promise->set_value(fut.get());
|
|
} catch (...) {
|
|
promise->set_exception(std::current_exception());
|
|
}
|
|
}});
|
|
return promise->get_future();
|
|
}
|
|
|
|
DownloadResult Downloader::download(const DownloadRequest & request)
|
|
{
|
|
return enqueueDownload(request).get();
|
|
}
|
|
|
|
void Downloader::download(DownloadRequest && request, Sink & sink)
|
|
{
|
|
/* Note: we can't call 'sink' via request.dataCallback, because
|
|
that would cause the sink to execute on the downloader
|
|
thread. If 'sink' is a coroutine, this will fail. Also, if the
|
|
sink is expensive (e.g. one that does decompression and writing
|
|
to the Nix store), it would stall the download thread too much.
|
|
Therefore we use a buffer to communicate data between the
|
|
download thread and the calling thread. */
|
|
|
|
struct State {
|
|
bool quit = false;
|
|
std::exception_ptr exc;
|
|
std::string data;
|
|
std::condition_variable avail, request;
|
|
};
|
|
|
|
auto _state = std::make_shared<Sync<State>>();
|
|
|
|
/* In case of an exception, wake up the download thread. FIXME:
|
|
abort the download request. */
|
|
Finally finally([&]() {
|
|
auto state(_state->lock());
|
|
state->quit = true;
|
|
state->request.notify_one();
|
|
});
|
|
|
|
request.dataCallback = [_state](char * buf, size_t len) {
|
|
|
|
auto state(_state->lock());
|
|
|
|
if (state->quit) return;
|
|
|
|
/* If the buffer is full, then go to sleep until the calling
|
|
thread wakes us up (i.e. when it has removed data from the
|
|
buffer). We don't wait forever to prevent stalling the
|
|
download thread. (Hopefully sleeping will throttle the
|
|
sender.) */
|
|
if (state->data.size() > 1024 * 1024) {
|
|
debug("download buffer is full; going to sleep");
|
|
state.wait_for(state->request, std::chrono::seconds(10));
|
|
}
|
|
|
|
/* Append data to the buffer and wake up the calling
|
|
thread. */
|
|
state->data.append(buf, len);
|
|
state->avail.notify_one();
|
|
};
|
|
|
|
enqueueDownload(request,
|
|
{[_state](std::future<DownloadResult> fut) {
|
|
auto state(_state->lock());
|
|
state->quit = true;
|
|
try {
|
|
fut.get();
|
|
} catch (...) {
|
|
state->exc = std::current_exception();
|
|
}
|
|
state->avail.notify_one();
|
|
state->request.notify_one();
|
|
}});
|
|
|
|
while (true) {
|
|
checkInterrupt();
|
|
|
|
std::string chunk;
|
|
|
|
/* Grab data if available, otherwise wait for the download
|
|
thread to wake us up. */
|
|
{
|
|
auto state(_state->lock());
|
|
|
|
while (state->data.empty()) {
|
|
|
|
if (state->quit) {
|
|
if (state->exc) std::rethrow_exception(state->exc);
|
|
return;
|
|
}
|
|
|
|
state.wait(state->avail);
|
|
}
|
|
|
|
chunk = std::move(state->data);
|
|
|
|
state->request.notify_one();
|
|
}
|
|
|
|
/* Flush the data to the sink and wake up the download thread
|
|
if it's blocked on a full buffer. We don't hold the state
|
|
lock while doing this to prevent blocking the download
|
|
thread if sink() takes a long time. */
|
|
sink((unsigned char *) chunk.data(), chunk.size());
|
|
}
|
|
}
|
|
|
|
CachedDownloadResult Downloader::downloadCached(
|
|
ref<Store> store, const CachedDownloadRequest & request)
|
|
{
|
|
auto url = resolveUri(request.uri);
|
|
|
|
auto name = request.name;
|
|
if (name == "") {
|
|
auto p = url.rfind('/');
|
|
if (p != string::npos) name = string(url, p + 1);
|
|
}
|
|
|
|
std::optional<StorePath> expectedStorePath;
|
|
if (request.expectedHash) {
|
|
expectedStorePath = store->makeFixedOutputPath(request.unpack, request.expectedHash, name);
|
|
if (store->isValidPath(*expectedStorePath)) {
|
|
CachedDownloadResult result;
|
|
result.storePath = store->printStorePath(*expectedStorePath);
|
|
result.path = store->toRealPath(result.storePath);
|
|
return result;
|
|
}
|
|
}
|
|
|
|
Path cacheDir = getCacheDir() + "/nix/tarballs";
|
|
createDirs(cacheDir);
|
|
|
|
string urlHash = hashString(htSHA256, name + std::string("\0"s) + url).to_string(Base32, false);
|
|
|
|
Path dataFile = cacheDir + "/" + urlHash + ".info";
|
|
Path fileLink = cacheDir + "/" + urlHash + "-file";
|
|
|
|
PathLocks lock({fileLink}, fmt("waiting for lock on '%1%'...", fileLink));
|
|
|
|
std::optional<StorePath> storePath;
|
|
|
|
string expectedETag;
|
|
|
|
bool skip = false;
|
|
|
|
CachedDownloadResult result;
|
|
|
|
if (pathExists(fileLink) && pathExists(dataFile)) {
|
|
storePath = store->parseStorePath(readLink(fileLink));
|
|
// FIXME
|
|
store->addTempRoot(*storePath);
|
|
if (store->isValidPath(*storePath)) {
|
|
auto ss = tokenizeString<vector<string>>(readFile(dataFile), "\n");
|
|
if (ss.size() >= 3 && ss[0] == url) {
|
|
time_t lastChecked;
|
|
if (string2Int(ss[2], lastChecked) && (uint64_t) lastChecked + request.ttl >= (uint64_t) time(0)) {
|
|
skip = true;
|
|
result.effectiveUri = request.uri;
|
|
result.etag = ss[1];
|
|
} else if (!ss[1].empty()) {
|
|
debug(format("verifying previous ETag '%1%'") % ss[1]);
|
|
expectedETag = ss[1];
|
|
}
|
|
}
|
|
} else
|
|
storePath.reset();
|
|
}
|
|
|
|
if (!skip) {
|
|
|
|
try {
|
|
DownloadRequest request2(url);
|
|
request2.expectedETag = expectedETag;
|
|
auto res = download(request2);
|
|
result.effectiveUri = res.effectiveUri;
|
|
result.etag = res.etag;
|
|
|
|
if (!res.cached) {
|
|
StringSink sink;
|
|
dumpString(*res.data, sink);
|
|
Hash hash = hashString(request.expectedHash ? request.expectedHash.type : htSHA256, *res.data);
|
|
ValidPathInfo info(store->makeFixedOutputPath(false, hash, name));
|
|
info.narHash = hashString(htSHA256, *sink.s);
|
|
info.narSize = sink.s->size();
|
|
info.ca = makeFixedOutputCA(false, hash);
|
|
store->addToStore(info, sink.s, NoRepair, NoCheckSigs);
|
|
storePath = info.path.clone();
|
|
}
|
|
|
|
assert(storePath);
|
|
replaceSymlink(store->printStorePath(*storePath), fileLink);
|
|
|
|
writeFile(dataFile, url + "\n" + res.etag + "\n" + std::to_string(time(0)) + "\n");
|
|
} catch (DownloadError & e) {
|
|
if (!storePath) throw;
|
|
warn("warning: %s; using cached result", e.msg());
|
|
result.etag = expectedETag;
|
|
}
|
|
}
|
|
|
|
if (request.unpack) {
|
|
Path unpackedLink = cacheDir + "/" + ((std::string) storePath->to_string()) + "-unpacked";
|
|
PathLocks lock2({unpackedLink}, fmt("waiting for lock on '%1%'...", unpackedLink));
|
|
std::optional<StorePath> unpackedStorePath;
|
|
if (pathExists(unpackedLink)) {
|
|
unpackedStorePath = store->parseStorePath(readLink(unpackedLink));
|
|
// FIXME
|
|
store->addTempRoot(*unpackedStorePath);
|
|
if (!store->isValidPath(*unpackedStorePath))
|
|
unpackedStorePath.reset();
|
|
}
|
|
if (!unpackedStorePath) {
|
|
printInfo("unpacking '%s'...", url);
|
|
Path tmpDir = createTempDir();
|
|
AutoDelete autoDelete(tmpDir, true);
|
|
unpackTarfile(store->toRealPath(store->printStorePath(*storePath)), tmpDir);
|
|
auto members = readDirectory(tmpDir);
|
|
if (members.size() != 1)
|
|
throw nix::Error("tarball '%s' contains an unexpected number of top-level files", url);
|
|
auto topDir = tmpDir + "/" + members.begin()->name;
|
|
unpackedStorePath = store->addToStore(name, topDir, true, htSHA256, defaultPathFilter, NoRepair);
|
|
}
|
|
replaceSymlink(store->printStorePath(*unpackedStorePath), unpackedLink);
|
|
storePath = std::move(*unpackedStorePath);
|
|
}
|
|
|
|
if (expectedStorePath && *storePath != *expectedStorePath) {
|
|
unsigned int statusCode = 102;
|
|
Hash gotHash = request.unpack
|
|
? hashPath(request.expectedHash.type, store->toRealPath(store->printStorePath(*storePath))).first
|
|
: hashFile(request.expectedHash.type, store->toRealPath(store->printStorePath(*storePath)));
|
|
throw nix::Error(statusCode, "hash mismatch in file downloaded from '%s':\n wanted: %s\n got: %s",
|
|
url, request.expectedHash.to_string(), gotHash.to_string());
|
|
}
|
|
|
|
result.storePath = store->printStorePath(*storePath);
|
|
result.path = store->toRealPath(result.storePath);
|
|
return result;
|
|
}
|
|
|
|
|
|
bool isUri(const string & s)
|
|
{
|
|
if (s.compare(0, 8, "channel:") == 0) return true;
|
|
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" || scheme == "git" || scheme == "s3" || scheme == "ssh";
|
|
}
|
|
|
|
|
|
}
|