dany/pdfio
1
0
Fork 0
mirror of https://github.com/michaelrsweet/pdfio.git synced 2025-08-29 15:22:06 +02:00
Code Issues Packages Projects Releases Wiki Activity

Clarify error callback API, and actually use the return value.

Browse Source 
Improve repair implementation.
This commit is contained in:
Michael R Sweet
2025-04-23 14:43:14 -04:00
parent 1e6bb710e3
commit 278ddb7fa7
7 changed files with 168 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

141
pdfio-file.c
View File

@@ -188,8 +188,9 @@ pdfioFileClose(pdfio_file_t *pdf) // I - PDF file
// of 8.27x11in (the intersection of US Letter and ISO A4) is used.
//
// The "error_cb" and "error_cbdata" arguments specify an error handler callback
// and its data pointer - if `NULL` the default error handler is used that
// writes error messages to `stderr`.
// and its data pointer - if `NULL` then the default error handler is used that
// writes error messages to `stderr`. The error handler callback should return
// `true` to continue writing the PDF file or `false` to stop.
//
pdfio_file_t * // O - PDF file or `NULL` on error
@@ -426,8 +427,9 @@ _pdfioFileCreateObj(
// of 8.27x11in (the intersection of US Letter and ISO A4) is used.
//
// The "error_cb" and "error_cbdata" arguments specify an error handler callback
// and its data pointer - if `NULL` the default error handler is used that
// writes error messages to `stderr`.
// and its data pointer - if `NULL` then the default error handler is used that
// writes error messages to `stderr`. The error handler callback should return
// `true` to continue writing the PDF file or `false` to stop.
//
// > *Note*: Files created using this API are slightly larger than those
// > created using the @link pdfioFileCreate@ function since stream lengths are
@@ -1019,8 +1021,14 @@ pdfioFileGetVersion(
// PDF file requires a password, the open will always fail.
//
// The "error_cb" and "error_cbdata" arguments specify an error handler callback
// and its data pointer - if `NULL` the default error handler is used that
// writes error messages to `stderr`.
// and its data pointer - if `NULL` then the default error handler is used that
// writes error messages to `stderr`. The error handler callback should return
// `true` to continue reading the PDF file or `false` to stop.
//
// > Note: Error messages starting with "WARNING:" are actually warning
// > messages - the callback should normally return `true` to allow PDFio to
// > try to resolve the issue. In addition, some errors are unrecoverable and
// > ignore the return value of the error callback.
//
pdfio_file_t * // O - PDF file
@@ -1119,16 +1127,20 @@ pdfioFileOpen(
if (ptr >= end)
{
_pdfioFileError(pdf, "Unable to find start of xref table.");
goto error;
}
xref_offset = (off_t)strtol(ptr + 9, NULL, 10);
if (!load_xref(pdf, xref_offset, password_cb, password_cbdata))
{
if (!repair_xref(pdf, password_cb, password_cbdata))
goto error;
}
else
{
xref_offset = (off_t)strtol(ptr + 9, NULL, 10);
if (!load_xref(pdf, xref_offset, password_cb, password_cbdata))
{
if (!repair_xref(pdf, password_cb, password_cbdata))
goto error;
}
}
return (pdf);
@@ -1755,7 +1767,10 @@ load_pages(pdfio_file_t *pdf, // I - PDF file
}
if ((type = pdfioDictGetName(dict, "Type")) == NULL || (strcmp(type, "Pages") && strcmp(type, "Page")))
return (false);
{
if (!_pdfioFileError(pdf, "WARNING: No Type value for pages object."))
return (false);
}
// If there is a Kids array, then this is a parent node and we have to look
// at the child objects...
@@ -1948,7 +1963,9 @@ load_xref(
w_2 = w[0];
w_3 = w[0] + w[1];
if (w[1] == 0 || w[2] > 4 || w[0] > sizeof(buffer) || w[1] > sizeof(buffer) || w[2] > sizeof(buffer) || w_total > sizeof(buffer))
PDFIO_DEBUG("W=[%u %u %u], w_total=%u\n", (unsigned)w[0], (unsigned)w[1], (unsigned)w[2], (unsigned)w_total);
if (pdfioArrayGetSize(w_array) > 3 || w[1] == 0 || w[2] > 4 || w[0] > sizeof(buffer) || w[1] > sizeof(buffer) || w[2] > sizeof(buffer) || w_total > sizeof(buffer))
{
_pdfioFileError(pdf, "Cross-reference stream has invalid W key [%u %u %u].", (unsigned)w[0], (unsigned)w[1], (unsigned)w[2]);
return (false);
@@ -1977,7 +1994,20 @@ load_xref(
{
count --;
PDFIO_DEBUG("load_xref: number=%u %02X%02X%02X%02X%02X\n", (unsigned)number, buffer[0], buffer[1], buffer[2], buffer[3], buffer[4]);
#ifdef DEBUG
if (w_total > 5)
PDFIO_DEBUG("load_xref: number=%u %02X%02X%02X%02X%02X...\n", (unsigned)number, buffer[0], buffer[1], buffer[2], buffer[3], buffer[4]);
else if (w_total == 5)
PDFIO_DEBUG("load_xref: number=%u %02X%02X%02X%02X%02X\n", (unsigned)number, buffer[0], buffer[1], buffer[2], buffer[3], buffer[4]);
else if (w_total == 4)
PDFIO_DEBUG("load_xref: number=%u %02X%02X%02X%02X\n", (unsigned)number, buffer[0], buffer[1], buffer[2], buffer[3]);
else if (w_total == 3)
PDFIO_DEBUG("load_xref: number=%u %02X%02X%02X\n", (unsigned)number, buffer[0], buffer[1], buffer[2]);
else if (w_total == 2)
PDFIO_DEBUG("load_xref: number=%u %02X%02X\n", (unsigned)number, buffer[0], buffer[1]);
else
PDFIO_DEBUG("load_xref: number=%u %02X\n", (unsigned)number, buffer[0]);
#endif // DEBUG
// Check whether this is an object definition...
if (w[0] > 0)
@@ -2288,7 +2318,7 @@ repair_xref(
pdfio_password_cb_t password_cb, // I - Password callback or `NULL` for none
void *password_data) // I - Password callback data, if any
{
char line[16384], // Line from file
char line[65536], // Line from file
*ptr; // Pointer into line
off_t line_offset; // Offset in file
intmax_t number; // Object number
@@ -2296,10 +2326,13 @@ repair_xref(
size_t i; // Looping var
size_t num_sobjs = 0; // Number of object streams
pdfio_obj_t *sobjs[16384]; // Object streams to load
pdfio_dict_t *backup_trailer = NULL; // Backup trailer dictionary
pdfio_obj_t *pages_obj; // Pages object
// Let caller know something is wrong...
_pdfioFileError(pdf, "WARNING: Cross-reference table is damaged, attempting to rebuild.");
if (!_pdfioFileError(pdf, "WARNING: Cross-reference table is damaged, attempting to rebuild."))
return (false);
// Read from the beginning of the file, looking for
if ((line_offset = _pdfioFileSeek(pdf, 0, SEEK_SET)) < 0)
@@ -2311,6 +2344,8 @@ repair_xref(
if (line[0] >= '1' && line[0] <= '9')
{
// Maybe, look some more...
PDFIO_DEBUG("repair_xref: line=\"%s\"\n", line);
if ((number = strtoimax(line, &ptr, 10)) >= 1 && (generation = (int)strtol(ptr, &ptr, 10)) >= 0 && generation < 65536)
{
while (isspace(*ptr & 255))
@@ -2322,7 +2357,7 @@ repair_xref(
pdfio_obj_t *obj; // Object
_pdfio_token_t tb; // Token buffer/stack
PDFIO_DEBUG("OBJECT %ld %d at offset %ld\n", (long)number, generation, (long)line_offset);
PDFIO_DEBUG("repair_xref: OBJECT %ld %d at offset %ld\n", (long)number, generation, (long)line_offset);
if ((obj = add_obj(pdf, (size_t)number, (unsigned short)generation, line_offset)) == NULL)
{
@@ -2338,27 +2373,46 @@ repair_xref(
return (false);
}
if (_pdfioTokenGet(&tb, line, sizeof(line)) && strcmp(line, "stream"))
if (_pdfioTokenGet(&tb, line, sizeof(line)))
{
const char *type = pdfioObjGetType(obj);
// Object type
_pdfioTokenFlush(&tb);
obj->stream_offset = _pdfioFileTell(pdf);
if (type && !strcmp(type, "ObjStm") && num_sobjs < (sizeof(sobjs) / sizeof(sobjs[0])))
{
sobjs[num_sobjs] = obj;
num_sobjs ++;
}
if (type && !strcmp(type, "XRef") && !pdf->trailer_dict)
if (type && !strcmp(line, "stream"))
{
// Save the trailer dictionary...
pdf->trailer_dict = pdfioObjGetDict(obj);
pdf->encrypt_obj = pdfioDictGetObj(pdf->trailer_dict, "Encrypt");
pdf->id_array = pdfioDictGetArray(pdf->trailer_dict, "ID");
}
// Possible object or XRef stream...
obj->stream_offset = _pdfioFileTell(pdf);
if (!strcmp(type, "ObjStm") && num_sobjs < (sizeof(sobjs) / sizeof(sobjs[0])))
{
PDFIO_DEBUG("repair_xref: Object stream...\n");
sobjs[num_sobjs] = obj;
num_sobjs ++;
}
if (!strcmp(type, "XRef") && !pdf->trailer_dict)
{
// Save the trailer dictionary...
PDFIO_DEBUG("repair_xref: XRef stream...\n");
pdf->trailer_dict = pdfioObjGetDict(obj);
pdf->encrypt_obj = pdfioDictGetObj(pdf->trailer_dict, "Encrypt");
pdf->id_array = pdfioDictGetArray(pdf->trailer_dict, "ID");
}
}
else if (type && !strcmp(line, "endobj"))
{
// Possible catalog or pages object...
if (!strcmp(type, "Catalog"))
{
PDFIO_DEBUG("repair_xref: Catalog (root) object...\n");
if (!backup_trailer)
backup_trailer = pdfioDictCreate(pdf);
pdfioDictSetObj(backup_trailer, "Root", obj);
}
}
}
}
}
@@ -2369,6 +2423,8 @@ repair_xref(
_pdfio_token_t tb; // Token buffer/stack
_pdfio_value_t trailer; // Trailer
PDFIO_DEBUG("repair_xref: line=\"%s\"\n", line);
if (line[7])
{
// Probably the start of the trailer dictionary, rewind the file so
@@ -2376,7 +2432,7 @@ repair_xref(
_pdfioFileSeek(pdf, line_offset + 7, SEEK_SET);
}
PDFIO_DEBUG("TRAILER at offset %ld\n", (long)line_offset);
PDFIO_DEBUG("repair_xref: TRAILER at offset %ld\n", (long)line_offset);
_pdfioTokenInit(&tb, pdf, (_pdfio_tconsume_cb_t)_pdfioFileConsume, (_pdfio_tpeek_cb_t)_pdfioFilePeek, pdf);
if (!_pdfioValueRead(pdf, NULL, &tb, &trailer, 0))
@@ -2396,6 +2452,8 @@ repair_xref(
{
// Save the trailer dictionary and grab the root (catalog) and info
// objects...
PDFIO_DEBUG("repair_xref: Using this trailer dictionary.\n");
pdf->trailer_dict = trailer.value.dict;
pdf->encrypt_obj = pdfioDictGetObj(pdf->trailer_dict, "Encrypt");
pdf->id_array = pdfioDictGetArray(pdf->trailer_dict, "ID");
@@ -2406,11 +2464,18 @@ repair_xref(
line_offset = _pdfioFileTell(pdf);
}
PDFIO_DEBUG("repair_xref: Stopped at line_offset=%lu\n", (unsigned long)line_offset);
if (!pdf->trailer_dict && backup_trailer)
pdf->trailer_dict = backup_trailer;
// If the trailer contains an Encrypt key, try unlocking the file...
if (pdf->encrypt_obj && !_pdfioCryptoUnlock(pdf, password_cb, password_data))
return (false);
// Load any stream objects...
PDFIO_DEBUG("repair_xref: Found %lu stream objects.\n", (unsigned long)num_sobjs);
for (i = 0; i < num_sobjs; i ++)
{
if (!load_obj_stream(sobjs[i]))
@@ -2429,8 +2494,16 @@ repair_xref(
PDFIO_DEBUG("repair_xref: Root=%p(%lu)\n", pdf->root_obj, (unsigned long)pdf->root_obj->number);
if ((pages_obj = pdfioDictGetObj(pdfioObjGetDict(pdf->root_obj), "Pages")) == NULL)
{
_pdfioFileError(pdf, "Missing Pages object.");
return (false);
}
PDFIO_DEBUG("repair_xref: Pages=%p(%lu)\n", pages_obj, (unsigned long)pages_obj->number);
// Load pages...
return (load_pages(pdf, pdfioDictGetObj(pdfioObjGetDict(pdf->root_obj), "Pages"), 0));
return (load_pages(pdf, pages_obj, 0));
}