context.h

#ifndef MUPDF_FITZ_CONTEXT_H
#define MUPDF_FITZ_CONTEXT_H

#include "mupdf/fitz/version.h"
#include "mupdf/fitz/system.h"

/*
	Contexts
*/

typedef struct fz_alloc_context_s fz_alloc_context;
typedef struct fz_error_context_s fz_error_context;
typedef struct fz_id_context_s fz_id_context;
typedef struct fz_warn_context_s fz_warn_context;
typedef struct fz_font_context_s fz_font_context;
typedef struct fz_colorspace_context_s fz_colorspace_context;
typedef struct fz_aa_context_s fz_aa_context;
typedef struct fz_locks_context_s fz_locks_context;
typedef struct fz_store_s fz_store;
typedef struct fz_glyph_cache_s fz_glyph_cache;
typedef struct fz_document_handler_context_s fz_document_handler_context;
typedef struct fz_context_s fz_context;

struct fz_alloc_context_s
{
	void *user;
	void *(*malloc)(void *, unsigned int);
	void *(*realloc)(void *, void *, unsigned int);
	void (*free)(void *, void *);
};

struct fz_error_context_s
{
	int top;
	struct {
		int code;
		fz_jmp_buf buffer;
	} stack[256];
	int errcode;
	char message[256];
};

void fz_var_imp(void *);
#define fz_var(var) fz_var_imp((void *)&(var))

/*
	Exception macro definitions. Just treat these as a black box - pay no
	attention to the man behind the curtain.
*/

#define fz_try(ctx) \
	if (fz_push_try(ctx->error) && \
		((ctx->error->stack[ctx->error->top].code = fz_setjmp(ctx->error->stack[ctx->error->top].buffer)) == 0))\
	{ do {

#define fz_always(ctx) \
		} while (0); \
	} \
	if (ctx->error->stack[ctx->error->top].code < 3) \
	{ \
		ctx->error->stack[ctx->error->top].code++; \
		do { \

#define fz_catch(ctx) \
		} while(0); \
	} \
	if (ctx->error->stack[ctx->error->top--].code > 1)

int fz_push_try(fz_error_context *ex);
FZ_NORETURN void fz_throw(fz_context *, int errcode, const char *, ...) __printflike(3, 4);
FZ_NORETURN void fz_rethrow(fz_context *);
FZ_NORETURN void fz_rethrow_message(fz_context *, const char *, ...)  __printflike(2, 3);
void fz_warn(fz_context *ctx, const char *fmt, ...) __printflike(2, 3);
const char *fz_caught_message(fz_context *ctx);
int fz_caught(fz_context *ctx);
void fz_rethrow_if(fz_context *ctx, int errcode);

enum
{
	FZ_ERROR_NONE = 0,
	FZ_ERROR_GENERIC = 1,
	FZ_ERROR_SYNTAX = 2,
	FZ_ERROR_TRYLATER = 3,
	FZ_ERROR_ABORT = 4,
	FZ_ERROR_COUNT
};

/*
	fz_flush_warnings: Flush any repeated warnings.

	Repeated warnings are buffered, counted and eventually printed
	along with the number of repetitions. Call fz_flush_warnings
	to force printing of the latest buffered warning and the
	number of repetitions, for example to make sure that all
	warnings are printed before exiting an application.

	Does not throw exceptions.
*/
void fz_flush_warnings(fz_context *ctx);

struct fz_context_s
{
	fz_alloc_context *alloc;
	fz_locks_context *locks;
	fz_id_context *id;
	fz_error_context *error;
	fz_warn_context *warn;
	fz_font_context *font;
	fz_colorspace_context *colorspace;
	fz_aa_context *aa;
	fz_store *store;
	fz_glyph_cache *glyph_cache;
	fz_document_handler_context *handler;
};

/*
	Specifies the maximum size in bytes of the resource store in
	fz_context. Given as argument to fz_new_context.

	FZ_STORE_UNLIMITED: Let resource store grow unbounded.

	FZ_STORE_DEFAULT: A reasonable upper bound on the size, for
	devices that are not memory constrained.
*/
enum {
	FZ_STORE_UNLIMITED = 0,
	FZ_STORE_DEFAULT = 256 << 20,
};

/*
	fz_new_context: Allocate context containing global state.

	The global state contains an exception stack, resource store,
	etc. Most functions in MuPDF take a context argument to be
	able to reference the global state. See fz_drop_context for
	freeing an allocated context.

	alloc: Supply a custom memory allocator through a set of
	function pointers. Set to NULL for the standard library
	allocator. The context will keep the allocator pointer, so the
	data it points to must not be modified or freed during the
	lifetime of the context.

	locks: Supply a set of locks and functions to lock/unlock
	them, intended for multi-threaded applications. Set to NULL
	when using MuPDF in a single-threaded applications. The
	context will keep the locks pointer, so the data it points to
	must not be modified or freed during the lifetime of the
	context.

	max_store: Maximum size in bytes of the resource store, before
	it will start evicting cached resources such as fonts and
	images. FZ_STORE_UNLIMITED can be used if a hard limit is not
	desired. Use FZ_STORE_DEFAULT to get a reasonable size.

	Does not throw exceptions, but may return NULL.
*/
fz_context *fz_new_context_imp(fz_alloc_context *alloc, fz_locks_context *locks, unsigned int max_store, const char *version);

#define fz_new_context(alloc, locks, max_store) fz_new_context_imp(alloc, locks, max_store, FZ_VERSION)

/*
	fz_clone_context: Make a clone of an existing context.

	This function is meant to be used in multi-threaded
	applications where each thread requires its own context, yet
	parts of the global state, for example caching, is shared.

	ctx: Context obtained from fz_new_context to make a copy of.
	ctx must have had locks and lock/functions setup when created.
	The two contexts will share the memory allocator, resource
	store, locks and lock/unlock functions. They will each have
	their own exception stacks though.

	Does not throw exception, but may return NULL.
*/
fz_context *fz_clone_context(fz_context *ctx);

/*
	fz_drop_context: Free a context and its global state.

	The context and all of its global state is freed, and any
	buffered warnings are flushed (see fz_flush_warnings). If NULL
	is passed in nothing will happen.

	Does not throw exceptions.
*/
void fz_drop_context(fz_context *ctx);

/*
	fz_aa_level: Get the number of bits of antialiasing we are
	using. Between 0 and 8.
*/
int fz_aa_level(fz_context *ctx);

/*
	fz_set_aa_level: Set the number of bits of antialiasing we should use.

	bits: The number of bits of antialiasing to use (values are clamped
	to within the 0 to 8 range).
*/
void fz_set_aa_level(fz_context *ctx, int bits);

/*
	Locking functions

	MuPDF is kept deliberately free of any knowledge of particular
	threading systems. As such, in order for safe multi-threaded
	operation, we rely on callbacks to client provided functions.

	A client is expected to provide FZ_LOCK_MAX number of mutexes,
	and a function to lock/unlock each of them. These may be
	recursive mutexes, but do not have to be.

	If a client does not intend to use multiple threads, then it
	may pass NULL instead of a lock structure.

	In order to avoid deadlocks, we have one simple rule
	internally as to how we use locks: We can never take lock n
	when we already hold any lock i, where 0 <= i <= n. In order
	to verify this, we have some debugging code, that can be
	enabled by defining FITZ_DEBUG_LOCKING.
*/

struct fz_locks_context_s
{
	void *user;
	void (*lock)(void *user, int lock);
	void (*unlock)(void *user, int lock);
};

enum {
	FZ_LOCK_ALLOC = 0,
	FZ_LOCK_FILE, /* Unused now */
	FZ_LOCK_FREETYPE,
	FZ_LOCK_GLYPHCACHE,
	FZ_LOCK_MAX
};

/*
	Memory Allocation and Scavenging:

	All calls to MuPDFs allocator functions pass through to the
	underlying allocators passed in when the initial context is
	created, after locks are taken (using the supplied locking function)
	to ensure that only one thread at a time calls through.

	If the underlying allocator fails, MuPDF attempts to make room for
	the allocation by evicting elements from the store, then retrying.

	Any call to allocate may then result in several calls to the underlying
	allocator, and result in elements that are only referred to by the
	store being freed.
*/

/*
	fz_malloc: Allocate a block of memory (with scavenging)

	size: The number of bytes to allocate.

	Returns a pointer to the allocated block. May return NULL if size is
	0. Throws exception on failure to allocate.
*/
void *fz_malloc(fz_context *ctx, unsigned int size);

/*
	fz_calloc: Allocate a zeroed block of memory (with scavenging)

	count: The number of objects to allocate space for.

	size: The size (in bytes) of each object.

	Returns a pointer to the allocated block. May return NULL if size
	and/or count are 0. Throws exception on failure to allocate.
*/
void *fz_calloc(fz_context *ctx, unsigned int count, unsigned int size);

/*
	fz_malloc_struct: Allocate storage for a structure (with scavenging),
	clear it, and (in Memento builds) tag the pointer as belonging to a
	struct of this type.

	CTX: The context.

	STRUCT: The structure type.

	Returns a pointer to allocated (and cleared) structure. Throws
	exception on failure to allocate.
*/
#define fz_malloc_struct(CTX, STRUCT) \
	((STRUCT *)Memento_label(fz_calloc(CTX,1,sizeof(STRUCT)), #STRUCT))

/*
	fz_malloc_array: Allocate a block of (non zeroed) memory (with
	scavenging). Equivalent to fz_calloc without the memory clearing.

	count: The number of objects to allocate space for.

	size: The size (in bytes) of each object.

	Returns a pointer to the allocated block. May return NULL if size
	and/or count are 0. Throws exception on failure to allocate.
*/
void *fz_malloc_array(fz_context *ctx, unsigned int count, unsigned int size);

/*
	fz_resize_array: Resize a block of memory (with scavenging).

	p: The existing block to resize

	count: The number of objects to resize to.

	size: The size (in bytes) of each object.

	Returns a pointer to the resized block. May return NULL if size
	and/or count are 0. Throws exception on failure to resize (original
	block is left unchanged).
*/
void *fz_resize_array(fz_context *ctx, void *p, unsigned int count, unsigned int size);

/*
	fz_strdup: Duplicate a C string (with scavenging)

	s: The string to duplicate.

	Returns a pointer to a duplicated string. Throws exception on failure
	to allocate.
*/
char *fz_strdup(fz_context *ctx, const char *s);

/*
	fz_free: Frees an allocation.

	Does not throw exceptions.
*/
void fz_free(fz_context *ctx, void *p);

/*
	fz_malloc_no_throw: Allocate a block of memory (with scavenging)

	size: The number of bytes to allocate.

	Returns a pointer to the allocated block. May return NULL if size is
	0. Returns NULL on failure to allocate.
*/
void *fz_malloc_no_throw(fz_context *ctx, unsigned int size);

/*
	fz_calloc_no_throw: Allocate a zeroed block of memory (with scavenging)

	count: The number of objects to allocate space for.

	size: The size (in bytes) of each object.

	Returns a pointer to the allocated block. May return NULL if size
	and/or count are 0. Returns NULL on failure to allocate.
*/
void *fz_calloc_no_throw(fz_context *ctx, unsigned int count, unsigned int size);

/*
	fz_malloc_array_no_throw: Allocate a block of (non zeroed) memory
	(with scavenging). Equivalent to fz_calloc_no_throw without the
	memory clearing.

	count: The number of objects to allocate space for.

	size: The size (in bytes) of each object.

	Returns a pointer to the allocated block. May return NULL if size
	and/or count are 0. Returns NULL on failure to allocate.
*/
void *fz_malloc_array_no_throw(fz_context *ctx, unsigned int count, unsigned int size);

/*
	fz_resize_array_no_throw: Resize a block of memory (with scavenging).

	p: The existing block to resize

	count: The number of objects to resize to.

	size: The size (in bytes) of each object.

	Returns a pointer to the resized block. May return NULL if size
	and/or count are 0. Returns NULL on failure to resize (original
	block is left unchanged).
*/
void *fz_resize_array_no_throw(fz_context *ctx, void *p, unsigned int count, unsigned int size);

/*
	fz_strdup_no_throw: Duplicate a C string (with scavenging)

	s: The string to duplicate.

	Returns a pointer to a duplicated string. Returns NULL on failure
	to allocate.
*/
char *fz_strdup_no_throw(fz_context *ctx, const char *s);

/*
	fz_gen_id: Generate an id (guaranteed unique within this family of
	contexts).
*/
int fz_gen_id(fz_context *ctx);

struct fz_warn_context_s
{
	char message[256];
	int count;
};

fz_context *fz_clone_context_internal(fz_context *ctx);

void fz_new_aa_context(fz_context *ctx);
void fz_drop_aa_context(fz_context *ctx);
void fz_copy_aa_context(fz_context *dst, fz_context *src);

void fz_new_document_handler_context(fz_context *ctx);
void fz_drop_document_handler_context(fz_context *ctx);
fz_document_handler_context *fz_keep_document_handler_context(fz_context *ctx);

/* Default allocator */
extern fz_alloc_context fz_alloc_default;

/* Default locks */
extern fz_locks_context fz_locks_default;

#if defined(MEMENTO) || defined(DEBUG)
#define FITZ_DEBUG_LOCKING
#endif

#ifdef FITZ_DEBUG_LOCKING

void fz_assert_lock_held(fz_context *ctx, int lock);
void fz_assert_lock_not_held(fz_context *ctx, int lock);
void fz_lock_debug_lock(fz_context *ctx, int lock);
void fz_lock_debug_unlock(fz_context *ctx, int lock);

#else

#define fz_assert_lock_held(A,B) do { } while (0)
#define fz_assert_lock_not_held(A,B) do { } while (0)
#define fz_lock_debug_lock(A,B) do { } while (0)
#define fz_lock_debug_unlock(A,B) do { } while (0)

#endif /* !FITZ_DEBUG_LOCKING */

static inline void
fz_lock(fz_context *ctx, int lock)
{
	fz_lock_debug_lock(ctx, lock);
	ctx->locks->lock(ctx->locks->user, lock);
}

static inline void
fz_unlock(fz_context *ctx, int lock)
{
	fz_lock_debug_unlock(ctx, lock);
	ctx->locks->unlock(ctx->locks->user, lock);
}

static inline void *
fz_keep_imp(fz_context *ctx, void *p, int *refs)
{
	if (p)
	{
		fz_lock(ctx, FZ_LOCK_ALLOC);
		if (*refs > 0)
			++*refs;
		fz_unlock(ctx, FZ_LOCK_ALLOC);
	}
	return p;
}

static inline void *
fz_keep_imp8(fz_context *ctx, void *p, int8_t *refs)
{
	if (p)
	{
		fz_lock(ctx, FZ_LOCK_ALLOC);
		if (*refs > 0)
			++*refs;
		fz_unlock(ctx, FZ_LOCK_ALLOC);
	}
	return p;
}

static inline int
fz_drop_imp(fz_context *ctx, void *p, int *refs)
{
	if (p)
	{
		int drop;
		fz_lock(ctx, FZ_LOCK_ALLOC);
		if (*refs > 0)
			drop = --*refs == 0;
		else
			drop = 0;
		fz_unlock(ctx, FZ_LOCK_ALLOC);
		return drop;
	}
	return 0;
}

static inline int
fz_drop_imp8(fz_context *ctx, void *p, int8_t *refs)
{
	if (p)
	{
		int drop;
		fz_lock(ctx, FZ_LOCK_ALLOC);
		if (*refs > 0)
			drop = --*refs == 0;
		else
			drop = 0;
		fz_unlock(ctx, FZ_LOCK_ALLOC);
		return drop;
	}
	return 0;
}

#endif