detect 416 complete file in partial by expected hash

If we have the expected hashes we can check with them if the file we
have in partial we got a 416 for is the expected file. We detected this
with same-size before, but not every server sends a good Content-Range
header with a 416 response.

3 files changed, 46 insertions, 11 deletions

diff --git a/methods/https.cc b/methods/https.cc
index c6b75d9ad..712e9ee73 100644
--- a/methods/https.cc
+++ b/methods/https.cc
@@ -40,7 +40,9 @@ using namespace std;
 struct APT_HIDDEN CURLUserPointer {
    HttpsMethod * const https;
    HttpsMethod::FetchResult * const Res;
-   CURLUserPointer(HttpsMethod * const https, HttpsMethod::FetchResult * const Res) : https(https), Res(Res) {}
+   HttpsMethod::FetchItem const * const Itm;
+   CURLUserPointer(HttpsMethod * const https, HttpsMethod::FetchResult * const Res,
+	 HttpsMethod::FetchItem const * const Itm) : https(https), Res(Res), Itm(Itm) {}
 };
 
 size_t
@@ -61,13 +63,32 @@ HttpsMethod::parse_header(void *buffer, size_t size, size_t nmemb, void *userp)
    {
       if (me->https->Server->Result != 416 && me->https->Server->StartPos != 0)
 	 ;
-      else if (me->https->Server->Result == 416 && me->https->Server->Size == me->https->File->FileSize())
+      else if (me->https->Server->Result == 416)
       {
-         me->https->Server->Result = 200;
-	 me->https->Server->StartPos = me->https->Server->Size;
-	 // the actual size is not important for https as curl will deal with it
-	 // by itself and e.g. doesn't bother us with transport-encoding…
-	 me->https->Server->JunkSize = std::numeric_limits<unsigned long long>::max();
+	 bool partialHit = false;
+	 if (me->Itm->ExpectedHashes.usable() == true)
+	 {
+	    Hashes resultHashes(me->Itm->ExpectedHashes);
+	    FileFd file(me->Itm->DestFile, FileFd::ReadOnly);
+	    me->https->Server->Size = file.FileSize();
+	    me->https->Server->Date = file.ModificationTime();
+	    resultHashes.AddFD(file);
+	    HashStringList const hashList = resultHashes.GetHashStringList();
+	    partialHit = (me->Itm->ExpectedHashes == hashList);
+	 }
+	 else if (me->https->Server->Result == 416 && me->https->Server->Size == me->https->File->FileSize())
+	    partialHit = true;
+
+	 if (partialHit == true)
+	 {
+	    me->https->Server->Result = 200;
+	    me->https->Server->StartPos = me->https->Server->Size;
+	    // the actual size is not important for https as curl will deal with it
+	    // by itself and e.g. doesn't bother us with transport-encoding…
+	    me->https->Server->JunkSize = std::numeric_limits<unsigned long long>::max();
+	 }
+	 else
+	    me->https->Server->StartPos = 0;
       }
       else
 	 me->https->Server->StartPos = 0;
@@ -221,7 +242,7 @@ bool HttpsMethod::Fetch(FetchItem *Itm)
    maybe_add_auth (Uri, _config->FindFile("Dir::Etc::netrc"));
 
    FetchResult Res;
-   CURLUserPointer userp(this, &Res);
+   CURLUserPointer userp(this, &Res, Itm);
    // callbacks
    curl_easy_setopt(curl, CURLOPT_URL, static_cast<string>(Uri).c_str());
    curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, parse_header);
diff --git a/methods/https.h b/methods/https.h
index 6e32e8d3d..57fc292ee 100644
--- a/methods/https.h
+++ b/methods/https.h
@@ -79,6 +79,7 @@ class HttpsMethod : public ServerMethod
    virtual bool Configuration(std::string Message);
    virtual ServerState * CreateServerState(URI uri);
    using pkgAcqMethod::FetchResult;
+   using pkgAcqMethod::FetchItem;
 
    HttpsMethod() : ServerMethod("1.2",Pipeline | SendConfig), File(NULL)
    {
diff --git a/methods/server.cc b/methods/server.cc
index 2116926b0..bd01c3e98 100644
--- a/methods/server.cc
+++ b/methods/server.cc
@@ -269,7 +269,7 @@ ServerMethod::DealWithHeaders(FetchResult &Res)
       Res.LastModified = Queue->LastModified;
       return IMS_HIT;
    }
-   
+
    /* Redirect
     *
     * Note that it is only OK for us to treat all redirection the same
@@ -314,7 +314,20 @@ ServerMethod::DealWithHeaders(FetchResult &Res)
       struct stat SBuf;
       if (stat(Queue->DestFile.c_str(),&SBuf) >= 0 && SBuf.st_size > 0)
       {
-	 if ((unsigned long long)SBuf.st_size == Server->Size)
+	 bool partialHit = false;
+	 if (Queue->ExpectedHashes.usable() == true)
+	 {
+	    Hashes resultHashes(Queue->ExpectedHashes);
+	    FileFd file(Queue->DestFile, FileFd::ReadOnly);
+	    Server->Size = file.FileSize();
+	    Server->Date = file.ModificationTime();
+	    resultHashes.AddFD(file);
+	    HashStringList const hashList = resultHashes.GetHashStringList();
+	    partialHit = (Queue->ExpectedHashes == hashList);
+	 }
+	 else if ((unsigned long long)SBuf.st_size == Server->Size)
+	    partialHit = true;
+	 if (partialHit == true)
 	 {
 	    // the file is completely downloaded, but was not moved
 	    if (Server->HaveContent == true)
@@ -351,7 +364,7 @@ ServerMethod::DealWithHeaders(FetchResult &Res)
    // This is some sort of 2xx 'data follows' reply
    Res.LastModified = Server->Date;
    Res.Size = Server->Size;
-   
+
    // Open the file
    delete File;
    File = new FileFd(Queue->DestFile,FileFd::WriteAny);