tool_getparam: add support for --longopt=value

If the long option name ends with an equals sign (`=`), the argument is
the text following on its right side.

This makes the command line parser accept this common style in addition
to the existing way to accept option arguments more similar to how other
command line tools do.

Example: `curl --user-agent=curl-2000 https://example.com/`

Change a few existing tests to use this syntax: 206, 1333, 1335, 1442

Closes #17789

docs/cmdline-opts/_OPTIONS.md

@@ -24,6 +24,9 @@ When --next is used, it resets the parser state and you start again with a
 clean option state, except for the options that are global. Global options
 retain their values and meaning even after --next.
 
+If the long option name ends with an equals sign (`=`), the argument is the
+text following on its right side. (Added in 8.16.0)
+
 The first argument that is exactly two dashes (`--`), marks the end of
 options; any argument after the end of options is interpreted as a URL
 argument even if it starts with a dash.

src/tool_getparam.c

@@ -2803,6 +2803,9 @@ static ParameterError opt_filestring(struct OperationConfig *config,
   return err;
 }
 
+/* the longest command line option, excluding the leading -- */
+#define MAX_OPTION_LEN 26
+
 ParameterError getparameter(const char *flag, /* f or -long-flag */
                             const char *nextarg,    /* NULL if unset */
                             bool *usedarg,    /* set to TRUE if the arg
@@ -2816,6 +2819,7 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
   bool toggle = TRUE; /* how to switch boolean options, on or off. Controlled
                          by using --OPTION or --no-OPTION */
   bool nextalloc = FALSE; /* if nextarg is allocated */
+  bool consumearg = TRUE; /* the argument comes separate */
   const struct LongShort *a = NULL;
   struct GlobalConfig *global = config->global;
   verbose_nopts = 0; /* options processed in `flag`*/
@@ -2827,6 +2831,8 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
     const char *word = ('-' == flag[0]) ? flag + 2 : flag;
     bool noflagged = FALSE;
     bool expand = FALSE;
+    const char *p;
+    struct Curl_str out;
 
     if(!strncmp(word, "no-", 3)) {
       /* disable this option but ignore the "no-" part when looking for it */
@@ -2840,7 +2846,21 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
       expand = TRUE;
     }
 
-    a = findlongopt(word);
+    p = word;
+    /* is there an '=' ? */
+    if(!curlx_str_until(&p, &out, MAX_OPTION_LEN, '=') &&
+       !curlx_str_single(&p, '=') ) {
+      /* there's an equal sign */
+      char tempword[MAX_OPTION_LEN + 1];
+      memcpy(tempword, curlx_str(&out), curlx_strlen(&out));
+      tempword[curlx_strlen(&out)] = 0;
+      a = findlongopt(tempword);
+      nextarg = p;
+      consumearg = FALSE; /* it is not separate */
+    }
+    else
+      a = findlongopt(word);
+
     if(a) {
       longopt = TRUE;
     }
@@ -2910,7 +2930,7 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
         break;
       }
       else {
-        *usedarg = TRUE; /* mark it as used */
+        *usedarg = consumearg; /* mark it as used */
       }
       if(a->desc & ARG_DEPR) {
         opt_depr(global, a);

tests/data/test1333

@@ -31,7 +31,7 @@ http
 HTTP POST zero length, chunked-encoded
 </name>
 <command>
--d "" --header "Transfer-Encoding: chunked" http://%HOSTIP:%HTTPPORT/%TESTNUMBER
+-d "" --header="Transfer-Encoding: chunked" http://%HOSTIP:%HTTPPORT/%TESTNUMBER
 </command>
 </client>
 

tests/data/test1335

@@ -30,7 +30,7 @@ http
 HTTP GET with -O without Content-Disposition, -D stdout
 </name>
 <command option="no-output,no-include">
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER -O -D - --output-dir %LOGDIR
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER -O -D - --output-dir="%LOGDIR"
 </command>
 </client>
 

tests/data/test1442

@@ -19,7 +19,7 @@ file
 Check --write-out with trailing \
 </name>
 <command>
-file://localhost/%FILE_PWD/%LOGDIR/non-existent-file.txt --write-out '\'
+file://localhost/%FILE_PWD/%LOGDIR/non-existent-file.txt --write-out='\'
 </command>
 </client>
 

tests/data/test206

@@ -80,7 +80,7 @@ digest
 HTTP proxy CONNECT auth Digest
 </name>
 <command>
-http://test.remote.haxx.se.%TESTNUMBER:8990/path/%TESTNUMBER0002 --proxy http://%HOSTIP:%HTTPPORT --proxy-user silly:person --proxy-digest --proxytunnel
+http://test.remote.haxx.se.%TESTNUMBER:8990/path/%TESTNUMBER0002 --proxy=http://%HOSTIP:%HTTPPORT --proxy-user=silly:person --proxy-digest --proxytunnel
 </command>
 </client>