Merge branch 'ye/http-accept-language'

Using environment variable LANGUAGE and friends on the client side,
HTTP-based transports now send Accept-Language when making requests.

* ye/http-accept-language:
http: add Accept-Language header if possible

diff --cc http.c
index 2cdf67d8307f3067673324647e681b0874565d55,8b659b66963c38c84c498a0850105e68668b1e16..efdab0979692153f016bdf1fdb1a2e782738f1bc
--- 1/http.c
--- 2/http.c
+++ b/http.c
@@@ -995,7 -991,142 +1000,143 @@@ static void extract_content_type(struc
                strbuf_addstr(charset, "ISO-8859-1");
  }
  
 +
+ /*
+  * Guess the user's preferred languages from the value in LANGUAGE environment
+  * variable and LC_MESSAGES locale category if NO_GETTEXT is not defined.
+  *
+  * The result can be a colon-separated list like "ko:ja:en".
+  */
+ static const char *get_preferred_languages(void)
+ {
+       const char *retval;
+ 
+       retval = getenv("LANGUAGE");
+       if (retval && *retval)
+               return retval;
+ 
+ #ifndef NO_GETTEXT
+       retval = setlocale(LC_MESSAGES, NULL);
+       if (retval && *retval &&
+               strcmp(retval, "C") &&
+               strcmp(retval, "POSIX"))
+               return retval;
+ #endif
+ 
+       return NULL;
+ }
+ 
+ static void write_accept_language(struct strbuf *buf)
+ {
+       /*
+        * MAX_DECIMAL_PLACES must not be larger than 3. If it is larger than
+        * that, q-value will be smaller than 0.001, the minimum q-value the
+        * HTTP specification allows. See
+        * http://tools.ietf.org/html/rfc7231#section-5.3.1 for q-value.
+        */
+       const int MAX_DECIMAL_PLACES = 3;
+       const int MAX_LANGUAGE_TAGS = 1000;
+       const int MAX_ACCEPT_LANGUAGE_HEADER_SIZE = 4000;
+       char **language_tags = NULL;
+       int num_langs = 0;
+       const char *s = get_preferred_languages();
+       int i;
+       struct strbuf tag = STRBUF_INIT;
+ 
+       /* Don't add Accept-Language header if no language is preferred. */
+       if (!s)
+               return;
+ 
+       /*
+        * Split the colon-separated string of preferred languages into
+        * language_tags array.
+        */
+       do {
+               /* collect language tag */
+               for (; *s && (isalnum(*s) || *s == '_'); s++)
+                       strbuf_addch(&tag, *s == '_' ? '-' : *s);
+ 
+               /* skip .codeset, @modifier and any other unnecessary parts */
+               while (*s && *s != ':')
+                       s++;
+ 
+               if (tag.len) {
+                       num_langs++;
+                       REALLOC_ARRAY(language_tags, num_langs);
+                       language_tags[num_langs - 1] = strbuf_detach(&tag, NULL);
+                       if (num_langs >= MAX_LANGUAGE_TAGS - 1) /* -1 for '*' */
+                               break;
+               }
+       } while (*s++);
+ 
+       /* write Accept-Language header into buf */
+       if (num_langs) {
+               int last_buf_len = 0;
+               int max_q;
+               int decimal_places;
+               char q_format[32];
+ 
+               /* add '*' */
+               REALLOC_ARRAY(language_tags, num_langs + 1);
+               language_tags[num_langs++] = "*"; /* it's OK; this won't be freed */
+ 
+               /* compute decimal_places */
+               for (max_q = 1, decimal_places = 0;
+                    max_q < num_langs && decimal_places <= MAX_DECIMAL_PLACES;
+                    decimal_places++, max_q *= 10)
+                       ;
+ 
+               sprintf(q_format, ";q=0.%%0%dd", decimal_places);
+ 
+               strbuf_addstr(buf, "Accept-Language: ");
+ 
+               for (i = 0; i < num_langs; i++) {
+                       if (i > 0)
+                               strbuf_addstr(buf, ", ");
+ 
+                       strbuf_addstr(buf, language_tags[i]);
+ 
+                       if (i > 0)
+                               strbuf_addf(buf, q_format, max_q - i);
+ 
+                       if (buf->len > MAX_ACCEPT_LANGUAGE_HEADER_SIZE) {
+                               strbuf_remove(buf, last_buf_len, buf->len - last_buf_len);
+                               break;
+                       }
+ 
+                       last_buf_len = buf->len;
+               }
+       }
+ 
+       /* free language tags -- last one is a static '*' */
+       for (i = 0; i < num_langs - 1; i++)
+               free(language_tags[i]);
+       free(language_tags);
+ }
+ 
+ /*
+  * Get an Accept-Language header which indicates user's preferred languages.
+  *
+  * Examples:
+  *   LANGUAGE= -> ""
+  *   LANGUAGE=ko:en -> "Accept-Language: ko, en; q=0.9, *; q=0.1"
+  *   LANGUAGE=ko_KR.UTF-8:sr@latin -> "Accept-Language: ko-KR, sr; q=0.9, *; q=0.1"
+  *   LANGUAGE=ko LANG=en_US.UTF-8 -> "Accept-Language: ko, *; q=0.1"
+  *   LANGUAGE= LANG=en_US.UTF-8 -> "Accept-Language: en-US, *; q=0.1"
+  *   LANGUAGE= LANG=C -> ""
+  */
+ static const char *get_accept_language(void)
+ {
+       if (!cached_accept_language) {
+               struct strbuf buf = STRBUF_INIT;
+               write_accept_language(&buf);
+               if (buf.len > 0)
+                       cached_accept_language = strbuf_detach(&buf, NULL);
+       }
+ 
+       return cached_accept_language;
+ }
+ 
  /* http_request() targets */
  #define HTTP_REQUEST_STRBUF   0
  #define HTTP_REQUEST_FILE     1

diff --cc remote-curl.c
Simple merge

diff --cc t/t5550-http-fetch-dumb.sh
Simple merge