refactor: use OutputIterator for url-escaped info hash strings (#3672)

libtransmission/announcer-http.cc

@@ -56,14 +56,10 @@ static tr_urlbuf announce_url_new(tr_session const* session, tr_announce_request
     auto url = tr_urlbuf{};
     auto out = std::back_inserter(url);
 
-    auto escaped_info_hash = std::array<char, SHA_DIGEST_LENGTH * 3 + 1>{};
-    tr_http_escape_sha1(std::data(escaped_info_hash), req->info_hash);
-
     fmt::format_to(
         out,
         "{url}"
-        "{sep}info_hash={info_hash}"
-        "&peer_id={peer_id}"
+        "{sep}peer_id={peer_id}"
         "&port={port}"
         "&uploaded={uploaded}"
         "&downloaded={downloaded}"
@@ -74,7 +70,6 @@ static tr_urlbuf announce_url_new(tr_session const* session, tr_announce_request
         "&supportcrypto=1",
         fmt::arg("url", req->announce_url),
         fmt::arg("sep", tr_strvContains(req->announce_url.sv(), '?') ? '&' : '?'),
-        fmt::arg("info_hash", std::data(escaped_info_hash)),
         fmt::arg("peer_id", std::string_view{ std::data(req->peer_id), std::size(req->peer_id) }),
         fmt::arg("port", req->port.host()),
         fmt::arg("uploaded", req->up),
@@ -83,6 +78,9 @@ static tr_urlbuf announce_url_new(tr_session const* session, tr_announce_request
         fmt::arg("numwant", req->numwant),
         fmt::arg("key", req->key));
 
+    fmt::format_to(out, "&info_hash=");
+    tr_http_escape(out, req->info_hash);
+
     if (session->encryptionMode() == TR_ENCRYPTION_REQUIRED)
     {
         fmt::format_to(out, "&requirecrypto=1");
@@ -652,12 +650,12 @@ static auto scrape_url_new(tr_scrape_request const* req)
     char delimiter = tr_strvContains(sv, '?') ? '&' : '?';
 
     auto scrape_url = tr_pathbuf{ sv };
+    auto out = std::back_inserter(scrape_url);
 
     for (int i = 0; i < req->info_hash_count; ++i)
     {
-        char str[SHA_DIGEST_LENGTH * 3 + 1];
-        tr_http_escape_sha1(str, req->info_hash[i]);
-        scrape_url.append(delimiter, "info_hash=", str);
+        fmt::format_to(out, "{}info_hash=", delimiter);
+        tr_http_escape(out, req->info_hash[i]);
         delimiter = '&';
     }
 

libtransmission/web-utils.cc

@@ -172,29 +172,6 @@ char const* tr_webGetResponseStr(long code)
     }
 }
 
-static bool is_rfc2396_alnum(uint8_t ch)
-{
-    return ('0' <= ch && ch <= '9') || ('A' <= ch && ch <= 'Z') || ('a' <= ch && ch <= 'z') || ch == '.' || ch == '-' ||
-        ch == '_' || ch == '~';
-}
-
-void tr_http_escape_sha1(char* out, tr_sha1_digest_t const& digest)
-{
-    for (auto const b : digest)
-    {
-        if (is_rfc2396_alnum(uint8_t(b)))
-        {
-            *out++ = (char)b;
-        }
-        else
-        {
-            out = fmt::format_to(out, FMT_STRING("%{:02x}"), unsigned(b));
-        }
-    }
-
-    *out = '\0';
-}
-
 //// URLs
 
 namespace

libtransmission/web-utils.h

@@ -111,7 +111,11 @@ void tr_http_escape(OutputIt out, std::string_view in, bool escape_reserved)
     }
 }
 
-void tr_http_escape_sha1(char* out, tr_sha1_digest_t const& digest);
+template<typename OutputIt>
+void tr_http_escape(OutputIt out, tr_sha1_digest_t const& digest)
+{
+    tr_http_escape(out, std::string_view{ reinterpret_cast<char const*>(digest.data()), std::size(digest) }, false);
+}
 
 char const* tr_webGetResponseStr(long response_code);
 

utils/show.cc

@@ -8,6 +8,7 @@
 #include <cinttypes> // PRIu64
 #include <cstdio>
 #include <ctime>
+#include <iterator>
 #include <string>
 #include <string_view>
 
@@ -339,14 +340,9 @@ void doScrape(tr_torrent_metainfo const& metainfo)
         }
 
         // build the full scrape URL
-        auto escaped = std::array<char, TR_SHA1_DIGEST_LEN * 3 + 1>{};
-        tr_http_escape_sha1(std::data(escaped), metainfo.infoHash());
         auto const scrape = tracker.scrape.sv();
-        auto const url = tr_urlbuf{ scrape,
-                                    tr_strvContains(scrape, '?') ? '&' : '?',
-                                    "info_hash="sv,
-                                    std::string_view{ std::data(escaped) } };
-
+        auto url = tr_urlbuf{ scrape, tr_strvContains(scrape, '?') ? '&' : '?', "info_hash="sv };
+        tr_http_escape(std::back_inserter(url), metainfo.infoHash());
         printf("%" TR_PRIsv " ... ", TR_PRIsv_ARG(url));
         fflush(stdout);