Move curl stuff into a separate file

3 files changed, 150 insertions, 112 deletions

diff --git a/src/libexpr/download.cc b/src/libexpr/download.cc
new file mode 100644
index 000000000..050e8d69c
--- /dev/null
+++ b/src/libexpr/download.cc
@@ -0,0 +1,128 @@
+#include "download.hh"
+#include "util.hh"
+#include "globals.hh"
+
+#include <curl/curl.h>
+
+namespace nix {
+
+struct Curl
+{
+    CURL * curl;
+    string data;
+    string etag, status, expectedETag;
+
+    struct curl_slist * requestHeaders;
+
+    static size_t writeCallback(void * contents, size_t size, size_t nmemb, void * userp)
+    {
+        Curl & c(* (Curl *) userp);
+        size_t realSize = size * nmemb;
+        c.data.append((char *) contents, realSize);
+        return realSize;
+    }
+
+    static size_t headerCallback(void * contents, size_t size, size_t nmemb, void * userp)
+    {
+        Curl & c(* (Curl *) userp);
+        size_t realSize = size * nmemb;
+        string line = string((char *) contents, realSize);
+        printMsg(lvlVomit, format("got header: %1%") % trim(line));
+        if (line.compare(0, 5, "HTTP/") == 0) { // new response starts
+            c.etag = "";
+            auto ss = tokenizeString<vector<string>>(line, " ");
+            c.status = ss.size() >= 2 ? ss[1] : "";
+        } else {
+            auto i = line.find(':');
+            if (i != string::npos) {
+                string name = trim(string(line, 0, i));
+                if (name == "ETag") { // FIXME: case
+                    c.etag = trim(string(line, i + 1));
+                    /* Hack to work around a GitHub bug: it sends
+                       ETags, but ignores If-None-Match. So if we get
+                       the expected ETag on a 200 response, then shut
+                       down the connection because we already have the
+                       data. */
+                    printMsg(lvlDebug, format("got ETag: %1%") % c.etag);
+                    if (c.etag == c.expectedETag && c.status == "200") {
+                        printMsg(lvlDebug, format("shutting down on 200 HTTP response with expected ETag"));
+                        return 0;
+                    }
+                }
+            }
+        }
+        return realSize;
+    }
+
+    Curl()
+    {
+        requestHeaders = 0;
+
+        curl = curl_easy_init();
+        if (!curl) throw Error("unable to initialize curl");
+
+        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
+        curl_easy_setopt(curl, CURLOPT_CAINFO, getEnv("SSL_CERT_FILE", "/etc/ssl/certs/ca-certificates.crt").c_str());
+        curl_easy_setopt(curl, CURLOPT_USERAGENT, ("Nix/" + nixVersion).c_str());
+        curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
+
+        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeCallback);
+        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *) &curl);
+
+        curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, headerCallback);
+        curl_easy_setopt(curl, CURLOPT_HEADERDATA, (void *) &curl);
+    }
+
+    ~Curl()
+    {
+        if (curl) curl_easy_cleanup(curl);
+        if (requestHeaders) curl_slist_free_all(requestHeaders);
+    }
+
+    bool fetch(const string & url, const string & expectedETag = "")
+    {
+        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
+
+        data.clear();
+
+        if (requestHeaders) {
+            curl_slist_free_all(requestHeaders);
+            requestHeaders = 0;
+        }
+
+        if (!expectedETag.empty()) {
+            this->expectedETag = expectedETag;
+            requestHeaders = curl_slist_append(requestHeaders, ("If-None-Match: " + expectedETag).c_str());
+        }
+
+        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, requestHeaders);
+
+        CURLcode res = curl_easy_perform(curl);
+        if (res == CURLE_WRITE_ERROR && etag == expectedETag) return false;
+        if (res != CURLE_OK)
+            throw Error(format("unable to download ‘%1%’: %2% (%3%)")
+                % url % curl_easy_strerror(res) % res);
+
+        long httpStatus = 0;
+        curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &httpStatus);
+        if (httpStatus == 304) return false;
+
+        return true;
+    }
+};
+
+
+DownloadResult downloadFile(string url, string expectedETag)
+{
+    DownloadResult res;
+    Curl curl;
+    if (curl.fetch(url, expectedETag)) {
+        res.cached = false;
+        res.data = curl.data;
+    } else
+        res.cached = true;
+    res.etag = curl.etag;
+    return res;
+}
+
+}
diff --git a/src/libexpr/download.hh b/src/libexpr/download.hh
new file mode 100644
index 000000000..aa4fd5083
--- /dev/null
+++ b/src/libexpr/download.hh
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "types.hh"
+#include <string>
+
+namespace nix {
+
+struct DownloadResult
+{
+    bool cached;
+    string data, etag;
+};
+
+DownloadResult downloadFile(string url, string expectedETag = "");
+
+}
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 03a3c8286..33ec26d26 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -9,6 +9,7 @@
 #include "json-to-value.hh"
 #include "names.hh"
 #include "eval-inline.hh"
+#include "download.hh"
 
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -18,8 +19,6 @@
 #include <cstring>
 #include <dlfcn.h>
 
-#include <curl/curl.h>
-
 
 namespace nix {
 
@@ -1486,112 +1485,6 @@ static void prim_compareVersions(EvalState & state, const Pos & pos, Value * * a
  *************************************************************/
 
 
-struct Curl
-{
-    CURL * curl;
-    string data;
-    string etag, status, expectedETag;
-
-    struct curl_slist * requestHeaders;
-
-    static size_t writeCallback(void * contents, size_t size, size_t nmemb, void * userp)
-    {
-        Curl & c(* (Curl *) userp);
-        size_t realSize = size * nmemb;
-        c.data.append((char *) contents, realSize);
-        return realSize;
-    }
-
-    static size_t headerCallback(void * contents, size_t size, size_t nmemb, void * userp)
-    {
-        Curl & c(* (Curl *) userp);
-        size_t realSize = size * nmemb;
-        string line = string((char *) contents, realSize);
-        printMsg(lvlVomit, format("got header: %1%") % trim(line));
-        if (line.compare(0, 5, "HTTP/") == 0) { // new response starts
-            c.etag = "";
-            auto ss = tokenizeString<vector<string>>(line, " ");
-            c.status = ss.size() >= 2 ? ss[1] : "";
-        } else {
-            auto i = line.find(':');
-            if (i != string::npos) {
-                string name = trim(string(line, 0, i));
-                if (name == "ETag") { // FIXME: case
-                    c.etag = trim(string(line, i + 1));
-                    /* Hack to work around a GitHub bug: it sends
-                       ETags, but ignores If-None-Match. So if we get
-                       the expected ETag on a 200 response, then shut
-                       down the connection because we already have the
-                       data. */
-                    printMsg(lvlDebug, format("got ETag: %1%") % c.etag);
-                    if (c.etag == c.expectedETag && c.status == "200") {
-                        printMsg(lvlDebug, format("shutting down on 200 HTTP response with expected ETag"));
-                        return 0;
-                    }
-                }
-            }
-        }
-        return realSize;
-    }
-
-    Curl()
-    {
-        requestHeaders = 0;
-
-        curl = curl_easy_init();
-        if (!curl) throw Error("unable to initialize curl");
-
-        curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
-        curl_easy_setopt(curl, CURLOPT_CAINFO, getEnv("SSL_CERT_FILE", "/etc/ssl/certs/ca-certificates.crt").c_str());
-        curl_easy_setopt(curl, CURLOPT_USERAGENT, ("Nix/" + nixVersion).c_str());
-        curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
-
-        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writeCallback);
-        curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *) &curl);
-
-        curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, headerCallback);
-        curl_easy_setopt(curl, CURLOPT_HEADERDATA, (void *) &curl);
-    }
-
-    ~Curl()
-    {
-        if (curl) curl_easy_cleanup(curl);
-        if (requestHeaders) curl_slist_free_all(requestHeaders);
-    }
-
-    bool fetch(const string & url, const string & expectedETag = "")
-    {
-        curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
-
-        data.clear();
-
-        if (requestHeaders) {
-            curl_slist_free_all(requestHeaders);
-            requestHeaders = 0;
-        }
-
-        if (!expectedETag.empty()) {
-            this->expectedETag = expectedETag;
-            requestHeaders = curl_slist_append(requestHeaders, ("If-None-Match: " + expectedETag).c_str());
-        }
-
-        curl_easy_setopt(curl, CURLOPT_HTTPHEADER, requestHeaders);
-
-        CURLcode res = curl_easy_perform(curl);
-        if (res == CURLE_WRITE_ERROR && etag == expectedETag) return false;
-        if (res != CURLE_OK)
-            throw Error(format("unable to download ‘%1%’: %2% (%3%)")
-                % url % curl_easy_strerror(res) % res);
-
-        long httpStatus = 0;
-        curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &httpStatus);
-        if (httpStatus == 304) return false;
-
-        return true;
-    }
-};
-
-
 void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
     const string & who, bool unpack)
 {
@@ -1662,15 +1555,16 @@ void fetch(EvalState & state, const Pos & pos, Value * * args, Value & v,
             printMsg(lvlInfo, format("downloading ‘%1%’...") % url);
         else
             printMsg(lvlInfo, format("checking ‘%1%’...") % url);
-        Curl curl;
 
-        if (curl.fetch(url, expectedETag))
-            storePath = store->addTextToStore(name, curl.data, PathSet(), state.repair);
+        auto res = downloadFile(url, expectedETag);
+
+        if (!res.cached)
+            storePath = store->addTextToStore(name, res.data, PathSet(), state.repair);
 
         assert(!storePath.empty());
         replaceSymlink(storePath, fileLink);
 
-        writeFile(dataFile, url + "\n" + curl.etag + "\n" + int2String(time(0)) + "\n");
+        writeFile(dataFile, url + "\n" + res.etag + "\n" + int2String(time(0)) + "\n");
     }
 
     if (unpack) {