Support linearized loading

public/fpdf_dataavail.h

Index: public/fpdf_dataavail.h
diff --git a/public/fpdf_dataavail.h b/public/fpdf_dataavail.h
index c17f0311ab3e599387f3efc1432433e19ea2cfc2..00f55870e7998355314b16fe9d66e0b02a1ab26e 100644
--- a/public/fpdf_dataavail.h
+++ b/public/fpdf_dataavail.h
@@ -11,10 +11,15 @@
 
 #include "fpdfview.h"
 
-/** The result of the process which check linearized PDF. */
-#define FSDK_IS_LINEARIZED 1
-#define FSDK_NOT_LINEARIZED 0
-#define FSDK_UNKNOW_LINEARIZED -1
+#define PDF_LINEARIZATION_UNKNOWN -1
+#define PDF_NOT_LINEARIZED 0
+#define PDF_LINEARIZED 1
+#define PDF_DATA_ERROR -1
+#define PDF_DATA_NOTAVAIL 0
+#define PDF_DATA_AVAIL 1
+#define PDF_FORM_NOTAVAIL 0
+#define PDF_FORM_AVAIL 1
+#define PDF_FORM_NOTEXIST 2
 
 #ifdef __cplusplus
 extern "C" {
@@ -130,17 +135,19 @@ typedef struct _FX_DOWNLOADHINTS {
 *           hints       -   Pointer to a download hints interface, receiving
 * generated hints
 * Return value:
-*           Non-zero for page is fully available, 0 for page not yet available.
+*           PDF_DATA_ERROR: A common error is returned. It can't tell

[Tom Sepez, 2015/10/21 17:53:08]

Public API change. Can we do what we need to do without breaking compatibliity?

[jun_fang, 2015/10/22 00:50:06]

This public API was designed for linearization functionality.
Before this CL, this functionality wasn't implemented correctly.
This is the first time that applications can call this API 
in the right way. So this API is almost a new API.

In the other hand, I define PDF_DATA_ERROR as -1. It follows the
legacy logic. Before this CL, it returns true even this are any
errors. So there are two possibilities for 'true', data available or error. Both
of them are non-zero.

+*                           whehter data are availabe or not.
+*           PDF_DATA_NOTAVAIL: Data are not yet available.
+*           PDF_DATA_AVAIL: Data are available.
 * Comments:
 *           The application should call this function whenever new data arrived,
 * and process all the
-*           generated download hints if any, until the function returns non-zero
-* value. Then the
-*           application can call FPDFAvail_GetDocument() to get a document
+*           generated download hints if any, until the function returns true.
+* Then the application can call FPDFAvail_GetDocument() to get a document
 * handle.
 */
-DLLEXPORT int STDCALL FPDFAvail_IsDocAvail(FPDF_AVAIL avail,
-                                           FX_DOWNLOADHINTS* hints);
+DLLEXPORT int STDCALL
+FPDFAvail_IsDocAvail(FPDF_AVAIL avail, FX_DOWNLOADHINTS* hints);
 
 /**
 * Function: FPDFAvail_GetDocument
@@ -189,15 +196,17 @@ DLLEXPORT int STDCALL FPDFAvail_GetFirstPageNum(FPDF_DOCUMENT doc);
 *           hints       -   Pointer to a download hints interface, receiving
 * generated hints
 * Return value:
-*           Non-zero for page is fully available, 0 for page not yet available.
+*           PDF_DATA_ERROR: A common error is returned. It can't tell
+*                           whehter data are availabe or not.
+*           PDF_DATA_NOTAVAIL: Data are not yet available.
+*           PDF_DATA_AVAIL: Data are available.
 * Comments:
 *           This function call be called only after FPDFAvail_GetDocument if
 * called.
 *           The application should call this function whenever new data arrived,
 * and process all the
-*           generated download hints if any, until the function returns non-zero
-* value. Then the
-*           application can perform page loading.
+*           generated download hints if any, until the function returns true.
+* Then the application can perform page loading.
 */
 DLLEXPORT int STDCALL FPDFAvail_IsPageAvail(FPDF_AVAIL avail,
                                             int page_index,
@@ -243,18 +252,19 @@ DLLEXPORT int STDCALL FPDFAvail_IsFormAvail(FPDF_AVAIL avail,
 *           avail       -   Handle to document availability provider returned by
 * FPDFAvail_Create
 * Return value:
-*           return TRUE means the document is linearized PDF else not.
-*           FSDK_IS_LINEARIZED is a linearize file.
-*           FSDK_NOT_LINEARIZED is not a linearize file.
-*           FSDK_UNKNOW_LINEARIZED don't know whether the file is a linearize
-* file.
+*           PDF_LINEARIZED is a linearize file.
+*           PDF_NOT_LINEARIZED is not a linearize file.
+*           PDF_LINEARIZATION_UNKNOWN doesn't know whether the file is a
+*linearize file.
+*
 * Comments:
-*           It return TRUE/FALSE as soon as we have first 1K data.  If the
-* file's size less than
-*           1K,we don't known whether the PDF is a linearized file.
+*           It return PDF_LINEARIZED or PDF_NOT_LINEARIZED as soon as
+*           we have first 1K data.  If the file's size less than 1K, it returns
+*           PDF_LINEARIZATION_UNKNOWN because there is not enough information to
+*           tell whether a PDF file is a linearized file or not.
 *
 */
-DLLEXPORT FPDF_BOOL STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail);
+DLLEXPORT int STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail);
 
 #ifdef __cplusplus
 }