Revert "mime: do not perform more than one read in a row"

This reverts commit ed0f357f7d25566110d4302f33759f4ffb5a6f83.

2 files changed, 50 insertions, 149 deletions

diff --git a/lib/mime.c b/lib/mime.c
index 7d754e63b..5f928a171 100644
--- a/lib/mime.c
+++ b/lib/mime.c
@@ -26,7 +26,6 @@
 
 #include "mime.h"
 #include "non-ascii.h"
-#include "warnless.h"
 #include "urldata.h"
 #include "sendf.h"
 
@@ -53,10 +52,6 @@
 
 
 #define READ_ERROR                      ((size_t) -1)
-#define STOP_FILLING                    ((size_t) -2)
-
-static size_t mime_subparts_read(char *buffer, size_t size, size_t nitems,
-                                 void *instream, bool *hasread);
 
 /* Encoders. */
 static size_t encoder_nop_read(char *buffer, size_t size, bool ateof,
@@ -359,15 +354,10 @@ static size_t encoder_nop_read(char *buffer, size_t size, bool ateof,
 
   (void) ateof;
 
-  if(!size)
-    return STOP_FILLING;
-
   if(size > insize)
     size = insize;
-
   if(size)
     memcpy(buffer, st->buf, size);
-
   st->bufbeg += size;
   return size;
 }
@@ -387,9 +377,6 @@ static size_t encoder_7bit_read(char *buffer, size_t size, bool ateof,
 
   (void) ateof;
 
-  if(!size)
-    return STOP_FILLING;
-
   if(size > cursize)
     size = cursize;
 
@@ -417,11 +404,8 @@ static size_t encoder_base64_read(char *buffer, size_t size, bool ateof,
     /* Line full ? */
     if(st->pos > MAX_ENCODED_LINE_LENGTH - 4) {
       /* Yes, we need 2 characters for CRLF. */
-      if(size < 2) {
-        if(!cursize)
-          return STOP_FILLING;
+      if(size < 2)
         break;
-      }
       *ptr++ = '\r';
       *ptr++ = '\n';
       st->pos = 0;
@@ -430,12 +414,7 @@ static size_t encoder_base64_read(char *buffer, size_t size, bool ateof,
     }
 
     /* Be sure there is enough space and input data for a base64 group. */
-    if(size < 4) {
-      if(!cursize)
-        return STOP_FILLING;
-      break;
-    }
-    if(st->bufend - st->bufbeg < 3)
+    if(size < 4 || st->bufend - st->bufbeg < 3)
       break;
 
     /* Encode three bytes as four characters. */
@@ -452,31 +431,25 @@ static size_t encoder_base64_read(char *buffer, size_t size, bool ateof,
   }
 
   /* If at eof, we have to flush the buffered data. */
-  if(ateof) {
-    if(size < 4) {
-      if(!cursize)
-        return STOP_FILLING;
-    }
-    else {
-      /* Buffered data size can only be 0, 1 or 2. */
-      ptr[2] = ptr[3] = '=';
-      i = 0;
-      switch(st->bufend - st->bufbeg) {
-      case 2:
-        i = (st->buf[st->bufbeg + 1] & 0xFF) << 8;
-        /* FALLTHROUGH */
-      case 1:
-        i |= (st->buf[st->bufbeg] & 0xFF) << 16;
-        ptr[0] = base64[(i >> 18) & 0x3F];
-        ptr[1] = base64[(i >> 12) & 0x3F];
-        if(++st->bufbeg != st->bufend) {
-          ptr[2] = base64[(i >> 6) & 0x3F];
-          st->bufbeg++;
-        }
-        cursize += 4;
-        st->pos += 4;
-        break;
+  if(ateof && size >= 4) {
+    /* Buffered data size can only be 0, 1 or 2. */
+    ptr[2] = ptr[3] = '=';
+    i = 0;
+    switch(st->bufend - st->bufbeg) {
+    case 2:
+      i = (st->buf[st->bufbeg + 1] & 0xFF) << 8;
+      /* FALLTHROUGH */
+    case 1:
+      i |= (st->buf[st->bufbeg] & 0xFF) << 16;
+      ptr[0] = base64[(i >> 18) & 0x3F];
+      ptr[1] = base64[(i >> 12) & 0x3F];
+      if(++st->bufbeg != st->bufend) {
+        ptr[2] = base64[(i >> 6) & 0x3F];
+        st->bufbeg++;
       }
+      cursize += 4;
+      st->pos += 4;
+      break;
     }
   }
 
@@ -608,11 +581,8 @@ static size_t encoder_qp_read(char *buffer, size_t size, bool ateof,
     }
 
     /* If the output buffer would overflow, do not store. */
-    if(len > size) {
-      if(!cursize)
-        return STOP_FILLING;
+    if(len > size)
       break;
-    }
 
     /* Append to output buffer. */
     memcpy(ptr, buf, len);
@@ -642,18 +612,16 @@ static size_t mime_mem_read(char *buffer, size_t size, size_t nitems,
                             void *instream)
 {
   curl_mimepart *part = (curl_mimepart *) instream;
-  size_t sz = curlx_sotouz(part->datasize - part->state.offset);
+  size_t sz = (size_t) part->datasize - part->state.offset;
   (void) size;   /* Always 1.*/
 
-  if(!nitems)
-    return STOP_FILLING;
-
   if(sz > nitems)
     sz = nitems;
 
   if(sz)
-    memcpy(buffer, part->data + curlx_sotouz(part->state.offset), sz);
+    memcpy(buffer, (char *) &part->data[part->state.offset], sz);
 
+  part->state.offset += sz;
   return sz;
 }
 
@@ -673,7 +641,7 @@ static int mime_mem_seek(void *instream, curl_off_t offset, int whence)
   if(offset < 0 || offset > part->datasize)
     return CURL_SEEKFUNC_FAIL;
 
-  part->state.offset = offset;
+  part->state.offset = (size_t) offset;
   return CURL_SEEKFUNC_OK;
 }
 
@@ -700,9 +668,6 @@ static size_t mime_file_read(char *buffer, size_t size, size_t nitems,
 {
   curl_mimepart *part = (curl_mimepart *) instream;
 
-  if(!nitems)
-    return STOP_FILLING;
-
   if(mime_open_file(part))
     return READ_ERROR;
 
@@ -746,16 +711,15 @@ static size_t readback_bytes(mime_state *state,
                              const char *trail)
 {
   size_t sz;
-  size_t offset = curlx_sotouz(state->offset);
 
-  if(numbytes > offset) {
-    sz = numbytes - offset;
-    bytes += offset;
+  if(numbytes > state->offset) {
+    sz = numbytes - state->offset;
+    bytes += state->offset;
   }
   else {
     size_t tsz = strlen(trail);
 
-    sz = offset - numbytes;
+    sz = state->offset - numbytes;
     if(sz >= tsz)
       return 0;
     bytes = trail + sz;
@@ -772,7 +736,7 @@ static size_t readback_bytes(mime_state *state,
 
 /* Read a non-encoded part content. */
 static size_t read_part_content(curl_mimepart *part,
-                                char *buffer, size_t bufsize, bool *hasread)
+                                char *buffer, size_t bufsize)
 {
   size_t sz = 0;
 
@@ -781,70 +745,26 @@ static size_t read_part_content(curl_mimepart *part,
   case CURL_READFUNC_ABORT:
   case CURL_READFUNC_PAUSE:
   case READ_ERROR:
-    return part->lastreadstatus;
-  default:
-    break;
-  }
-
-  /* If we can determine we are at end of part data, spare a read. */
-  if(part->datasize != (curl_off_t) -1 &&
-     part->state.offset >= part->datasize) {
-    /* sz is already zero. */
-  }
-  else {
-    switch(part->kind) {
-    case MIMEKIND_MULTIPART:
-      /*
-       * Cannot be processed as other kinds since read function requires
-       * an additional parameter and is highly recursive.
-       */
-       sz = mime_subparts_read(buffer, 1, bufsize, part->arg, hasread);
-       break;
-    case MIMEKIND_FILE:
-      if(part->fp && feof(part->fp))
-        break;  /* At EOF. */
-      /* FALLTHROUGH */
-    default:
-      if(part->readfunc) {
-        if(!(part->flags & MIME_FAST_READ)) {
-          if(*hasread)
-            return STOP_FILLING;
-          *hasread = TRUE;
-        }
-        sz = part->readfunc(buffer, 1, bufsize, part->arg);
-      }
-      break;
-    }
-  }
-
-  switch(sz) {
-  case STOP_FILLING:
-    break;
-  case 0:
-  case CURL_READFUNC_ABORT:
-  case CURL_READFUNC_PAUSE:
-  case READ_ERROR:
-    part->lastreadstatus = sz;
     break;
   default:
-    part->state.offset += sz;
+    if(part->readfunc)
+      sz = part->readfunc(buffer, 1, bufsize, part->arg);
     part->lastreadstatus = sz;
     break;
   }
-
-  return sz;
+  return part->lastreadstatus;
 }
 
 /* Read and encode part content. */
-static size_t read_encoded_part_content(curl_mimepart *part, char *buffer,
-                                        size_t bufsize, bool *hasread)
+static size_t read_encoded_part_content(curl_mimepart *part,
+                                        char *buffer, size_t bufsize)
 {
   mime_encoder_state *st = &part->encstate;
   size_t cursize = 0;
   size_t sz;
   bool ateof = FALSE;
 
-  for(;;) {
+  while(bufsize) {
     if(st->bufbeg < st->bufend || ateof) {
       /* Encode buffered data. */
       sz = part->encoder->encodefunc(buffer, bufsize, ateof, part);
@@ -853,8 +773,9 @@ static size_t read_encoded_part_content(curl_mimepart *part, char *buffer,
         if(ateof)
           return cursize;
         break;
+      case CURL_READFUNC_ABORT:
+      case CURL_READFUNC_PAUSE:
       case READ_ERROR:
-      case STOP_FILLING:
         return cursize? cursize: sz;
       default:
         cursize += sz;
@@ -876,7 +797,7 @@ static size_t read_encoded_part_content(curl_mimepart *part, char *buffer,
     if(st->bufend >= sizeof(st->buf))
       return cursize? cursize: READ_ERROR;    /* Buffer full. */
     sz = read_part_content(part, st->buf + st->bufend,
-                           sizeof(st->buf) - st->bufend, hasread);
+                           sizeof(st->buf) - st->bufend);
     switch(sz) {
     case 0:
       ateof = TRUE;
@@ -884,7 +805,6 @@ static size_t read_encoded_part_content(curl_mimepart *part, char *buffer,
     case CURL_READFUNC_ABORT:
     case CURL_READFUNC_PAUSE:
     case READ_ERROR:
-    case STOP_FILLING:
       return cursize? cursize: sz;
     default:
       st->bufend += sz;
@@ -892,12 +812,12 @@ static size_t read_encoded_part_content(curl_mimepart *part, char *buffer,
     }
   }
 
-  /* NOTREACHED */
+  return cursize;
 }
 
 /* Readback a mime part. */
 static size_t readback_part(curl_mimepart *part,
-                            char *buffer, size_t bufsize, bool *hasread)
+                            char *buffer, size_t bufsize)
 {
   size_t cursize = 0;
 #ifdef CURL_DOES_CONVERSIONS
@@ -956,9 +876,9 @@ static size_t readback_part(curl_mimepart *part,
       break;
     case MIMESTATE_CONTENT:
       if(part->encoder)
-        sz = read_encoded_part_content(part, buffer, bufsize, hasread);
+        sz = read_encoded_part_content(part, buffer, bufsize);
       else
-        sz = read_part_content(part, buffer, bufsize, hasread);
+        sz = read_part_content(part, buffer, bufsize);
       switch(sz) {
       case 0:
         mimesetstate(&part->state, MIMESTATE_END, NULL);
@@ -971,7 +891,6 @@ static size_t readback_part(curl_mimepart *part,
       case CURL_READFUNC_ABORT:
       case CURL_READFUNC_PAUSE:
       case READ_ERROR:
-      case STOP_FILLING:
         return cursize? cursize: sz;
       }
       break;
@@ -1000,9 +919,9 @@ static size_t readback_part(curl_mimepart *part,
   return cursize;
 }
 
-/* Readback from mime. Warning: not a read callback function. */
+/* Readback from mime. */
 static size_t mime_subparts_read(char *buffer, size_t size, size_t nitems,
-                                 void *instream, bool *hasread)
+                                 void *instream)
 {
   curl_mime *mime = (curl_mime *) instream;
   size_t cursize = 0;
@@ -1023,7 +942,7 @@ static size_t mime_subparts_read(char *buffer, size_t size, size_t nitems,
 #endif
       mimesetstate(&mime->state, MIMESTATE_BOUNDARY1, mime->firstpart);
       /* The first boundary always follows the header termination empty line,
-         so is always preceded by a CRLF. We can then spare 2 characters
+         so is always preceded by a CRLK. We can then spare 2 characters
          by skipping the leading CRLF in boundary. */
       mime->state.offset += 2;
       break;
@@ -1053,12 +972,11 @@ static size_t mime_subparts_read(char *buffer, size_t size, size_t nitems,
         mimesetstate(&mime->state, MIMESTATE_END, NULL);
         break;
       }
-      sz = readback_part(part, buffer, nitems, hasread);
+      sz = readback_part(part, buffer, nitems);
       switch(sz) {
       case CURL_READFUNC_ABORT:
       case CURL_READFUNC_PAUSE:
       case READ_ERROR:
-      case STOP_FILLING:
         return cursize? cursize: sz;
       case 0:
 #ifdef CURL_DOES_CONVERSIONS
@@ -1166,7 +1084,6 @@ static void cleanup_part_content(curl_mimepart *part)
   part->datasize = (curl_off_t) 0;    /* No size yet. */
   cleanup_encoder_state(&part->encstate);
   part->kind = MIMEKIND_NONE;
-  part->flags &= ~MIME_FAST_READ;
   part->lastreadstatus = 1; /* Successful read status. */
 }
 
@@ -1424,7 +1341,6 @@ CURLcode curl_mime_data(curl_mimepart *part,
     part->readfunc = mime_mem_read;
     part->seekfunc = mime_mem_seek;
     part->freefunc = mime_mem_free;
-    part->flags |= MIME_FAST_READ;
     part->kind = MIMEKIND_DATA;
   }
 
@@ -1599,7 +1515,7 @@ CURLcode Curl_mime_set_subparts(curl_mimepart *part,
     }
 
     subparts->parent = part;
-    /* Subparts are processed internally: no read callback. */
+    part->readfunc = mime_subparts_read;
     part->seekfunc = mime_subparts_seek;
     part->freefunc = take_ownership? mime_subparts_free: mime_subparts_unbind;
     part->arg = subparts;
@@ -1621,23 +1537,9 @@ CURLcode curl_mime_subparts(curl_mimepart *part, curl_mime *subparts)
 size_t Curl_mime_read(char *buffer, size_t size, size_t nitems, void *instream)
 {
   curl_mimepart *part = (curl_mimepart *) instream;
-  size_t ret;
-  bool hasread;
 
   (void) size;   /* Always 1. */
-
-  do {
-    hasread = FALSE;
-    ret = readback_part(part, buffer, nitems, &hasread);
-    /*
-     * If this is not possible to get some data without calling more than
-     * one read callback (probably because a content encoder is not able to
-     * deliver a new bunch for the few data accumulated so far), force another
-     * read until we get enough data or a special exit code.
-     */
-  } while(ret == STOP_FILLING);
-
-  return ret;
+  return readback_part(part, buffer, nitems);
 }
 
 /* Rewind mime stream. */
diff --git a/lib/mime.h b/lib/mime.h
index d7f25132e..c6d374ec1 100644
--- a/lib/mime.h
+++ b/lib/mime.h
@@ -31,7 +31,6 @@
 /* Part flags. */
 #define MIME_USERHEADERS_OWNER  (1 << 0)
 #define MIME_BODY_ONLY          (1 << 1)
-#define MIME_FAST_READ          (1 << 2)
 
 #define FILE_CONTENTTYPE_DEFAULT        "application/octet-stream"
 #define MULTIPART_CONTENTTYPE_DEFAULT   "multipart/mixed"
@@ -88,7 +87,7 @@ typedef struct {
 typedef struct {
   enum mimestate state;       /* Current state token. */
   void *ptr;                  /* State-dependent pointer. */
-  curl_off_t offset;          /* State-dependent offset. */
+  size_t offset;              /* State-dependent offset. */
 }  mime_state;
 
 /* minimum buffer size for the boundary string */