Add true streaming (initial commit)

Tests are still missing.
It works with luajit, but produces slightly wrong images with Lua 5.2, 5.3 and crashes with Lua 5.4

Author: rolandlo

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to `lua-vips` will be documented in this file.
 
 # master
 
+- add `vips.Connection`, `vips.Source` and `vips.Target` for true streaming support [rolandlo]
+  
 # 1.1-11 - 2024-04-16
 
 - add standard Lua support [rolandlo]

lua-vips-1.1-11.rockspec

@@ -47,6 +47,9 @@ build = {
        ["vips.voperation"] = "src/vips/voperation.lua",
        ["vips.Image"] = "src/vips/Image.lua",
        ["vips.Image_methods"] = "src/vips/Image_methods.lua",
-       ["vips.Interpolate"] = "src/vips/Interpolate.lua"
+       ["vips.Interpolate"] = "src/vips/Interpolate.lua",
+       ["vips.Connection"] = "src/vips/Connection.lua",
+       ["vips.Source"] = "src/vips/Source.lua",
+       ["vips.Target"] = "src/vips/Target.lua",
    }
 }

src/vips.lua

@@ -23,6 +23,9 @@ local vips = {
     voperation = require "vips.voperation",
     Image = require "vips.Image_methods",
     Interpolate = require "vips.Interpolate",
+    Connection = require "vips.Connection",
+    Source = require "vips.Source",
+    Target = require "vips.Target",
 }
 
 function vips.leak_set(leak)

src/vips/Connection.lua

@@ -0,0 +1,43 @@
+-- abstract base Connection class
+
+local ffi = require "ffi"
+
+local vobject = require "vips.vobject"
+
+local vips_lib = ffi.load(ffi.os == "Windows" and "libvips-42.dll" or "vips")
+
+local Connection = {}
+
+Connection.vobject = function(self)
+    return ffi.cast(vobject.typeof, self)
+end
+
+Connection.new = function(self)
+    return vobject.new(self)
+end
+Connection.filename = function(self)
+    -- Get the filename asscoiated with a connection. Return nil if there is no associated file.
+    local so = ffi.cast('VipsConnection *', self.pointer)
+    local filename = vips_lib.vips_connection_filename(so)
+    if filename == ffi.NULL then
+        return nil
+    else
+        return ffi.string(filename)
+    end
+end
+
+Connection.nick = function(self)
+    -- Make a human-readable name for a connection suitable for error messages.
+
+    local so = ffi.cast('VipsConnection *', self.pointer)
+    local nick = vips_lib.vips_connection_nick(so)
+    if nick == ffi.NULL then
+        return nil
+    else
+        return ffi.string(nick)
+    end
+end
+
+return ffi.metatype("VipsConnection", {
+    __index = Connection
+})

src/vips/Image_methods.lua

@@ -218,6 +218,14 @@ function Image.new_from_image(base_image, value)
     return image
 end
 
+function Image.new_from_source(source, options, ...)
+    local name = vips_lib.vips_foreign_find_load_source(source.vobject)
+    if name == ffi.NULL then
+        error("Unable to load from source")
+    end
+
+    return voperation.call(ffi.string(name), options, source, unpack { ... })
+end
 -- overloads
 
 function Image.mt.__add(a, b)
@@ -413,6 +421,18 @@ function Image_method:write_to_memory_ptr()
     return ffi.gc(vips_memory, glib_lib.g_free), tonumber(psize[0])
 end
 
+function Image_method:write_to_target(target, format_string, ...)
+    collectgarbage("stop")
+    local options = to_string_copy(vips_lib.vips_filename_get_options(format_string))
+    local name = vips_lib.vips_foreign_find_save_target(format_string)
+    collectgarbage("restart")
+    if name == ffi.NULL then
+        error(verror.get())
+    end
+    print(ffi.string(name), options, target)
+
+    return voperation.call(ffi.string(name), options, self, target, unpack { ... })
+end
 -- get/set metadata
 
 function Image_method:get_typeof(name)

src/vips/Source.lua

@@ -0,0 +1,46 @@
+-- An input connection
+
+local ffi = require "ffi"
+
+local verror = require "vips.verror"
+local vobject = require "vips.vobject"
+local Connection = require "vips.Connection"
+
+local vips_lib = ffi.load(ffi.os == "Windows" and "libvips-42.dll" or "vips")
+
+local Source = {}
+
+Source.vobject = function(self)
+    return ffi.cast(vobject.typeof, self)
+end
+
+Source.new_from_descriptor = function(descriptor)
+    local source = vips_lib.vips_source_new_from_descriptor(descriptor)
+    if source == ffi.NULL then
+        error("Can't create source from descriptor " .. descriptor .. "\n" .. verror.get())
+    end
+
+    return Connection.new(source)
+end
+
+Source.new_from_file = function(filename)
+    local source = vips_lib.vips_source_new_from_file(filename)
+    if source == ffi.NULL then
+        error("Can't create source from filename " .. filename .. "\n" .. verror.get())
+    end
+
+    return Connection.new(source)
+end
+
+Source.new_from_memory = function(data) -- data is an FFI memory array formatted as a C-style array
+    local source = vips_lib.vips_source_new_from_memory(data, ffi.sizeof(data))
+    if source == ffi.NULL then
+        error("Can't create input source from memory \n" .. verror.get())
+    end
+
+    return Connection.new(source)
+end
+
+return ffi.metatype("VipsSource", {
+    __index = Source
+})

src/vips/Target.lua

@@ -0,0 +1,45 @@
+-- An input connection
+
+local ffi = require "ffi"
+
+local vobject = require "vips.vobject"
+local Connection = require "vips.Connection"
+
+local vips_lib = ffi.load(ffi.os == "Windows" and "libvips-42.dll" or "vips")
+
+local Target = {}
+
+Target.vobject = function(self)
+    return ffi.cast(vobject.typeof, self)
+end
+
+Target.new_to_descriptor = function(descriptor)
+    local target = vips_lib.vips_target_new_to_descriptor(descriptor)
+    if target == ffi.NULL then
+        error("can't create output target from descriptor " .. descriptor)
+    else
+        return Connection.new(target)
+    end
+end
+
+Target.new_to_file = function(filename)
+    local target = vips_lib.vips_target_new_to_file(filename)
+    if target == ffi.NULL then
+        error("can't create output target from filename " .. filename)
+    else
+        return Connection.new(target)
+    end
+end
+
+Target.new_to_memory = function()
+    local target = vips_lib.vips_target_new_to_memory()
+    if target == ffi.NULL then
+        error("can't create output target from memory")
+    else
+        return Connection.new(target)
+    end
+end
+
+return ffi.metatype("VipsTarget", {
+    __index = Target
+})

src/vips/cdefs.lua

@@ -166,10 +166,71 @@ ffi.cdef [[
         // opaque
     } VipsImage;
 
+    typedef struct _VipsConnection {
+        VipsObject parent_instance;
+
+        // opaque
+    } VipsConnection;
+
+    const char *vips_connection_filename (VipsConnection *connection);
+    const char *vips_connection_nick (VipsConnection *connection);
+
+    typedef struct _VipsSource {
+        VipsConnection parent_instance;
+
+        // opaque
+    } VipsSource;
+
+    typedef struct _VipsTarget {
+        VipsConnection parent_instance;
+
+        // opaque
+    } VipsTarget;
+
+    VipsSource *vips_source_new_from_descriptor (int descriptor);
+    VipsSource *vips_source_new_from_file (const char *filename);
+    // VipsSource *vips_source_new_from_blob (VipsBlob *blob);
+    // VipsSource *vips_source_new_from_target (VipsTarget *target);
+    VipsSource *vips_source_new_from_memory (const void *data, size_t size);
+    // VipsSource *vips_source_new_from_options (const char *options);
+    // void vips_source_minimise (VipsSource *source);
+    // int vips_source_decode (VipsSource *source);
+    // gint64 vips_source_read (VipsSource *source, void *data, size_t length);
+    // gboolean vips_source_is_mappable (VipsSource *source);
+    // gboolean vips_source_is_file (VipsSource *source);
+    // const void *vips_source_map (VipsSource *source, size_t *length);
+    // VipsBlob *vips_source_map_blob (VipsSource *source);
+    // gint64 vips_source_seek (VipsSource *source, gint64 offset, int whence);
+    // int vips_source_rewind (VipsSource *source);
+    // gint64 vips_source_sniff_at_most (VipsSource *source, unsigned char **data, size_t length);
+    // unsigned char *vips_source_sniff (VipsSource *source, size_t length);
+    // gint64 vips_source_length (VipsSource *source);
+    // VipsSourceCustom *vips_source_custom_new (void);
+    // GInputStream *vips_g_input_stream_new_from_source (VipsSource *source);
+    // VipsSourceGInputStream *vips_source_g_input_stream_new (GInputStream *stream);
+
+    VipsTarget *vips_target_new_to_descriptor (int descriptor);
+    VipsTarget *vips_target_new_to_file (const char *filename);
+    VipsTarget *vips_target_new_to_memory (void);
+    // VipsTarget *vips_target_new_temp (VipsTarget *target);
+    // int vips_target_write (VipsTarget *target, const void *data, size_t length);
+    // gint64 vips_target_read (VipsTarget *target, void *buffer, size_t length);
+    // gint64 vips_target_seek (VipsTarget *target, gint64 offset, int whence);
+    // int vips_target_end (VipsTarget *target);
+    // unsigned char *vips_target_steal (VipsTarget *target, size_t *length);
+    // char *vips_target_steal_text (VipsTarget *target);
+    // int vips_target_putc (VipsTarget *target, int ch);
+    // int vips_target_writes (VipsTarget *target, const char *str);
+    // int vips_target_writef (VipsTarget *target, const char *fmt, ...);
+    // int vips_target_write_amp (VipsTarget *target, const char *str);
+    // VipsTargetCustom *vips_target_custom_new (void);
+
     const char *vips_foreign_find_load (const char *name);
     const char *vips_foreign_find_load_buffer (const void *data, size_t size);
     const char *vips_foreign_find_save (const char *name);
     const char *vips_foreign_find_save_buffer (const char *suffix);
+    const char* vips_foreign_find_load_source (VipsSource *source);
+    const char* vips_foreign_find_save_target (const char* suffix);
 
     VipsImage *vips_image_new_matrix_from_array (int width, int height,
         const double *array, int size);

src/vips/gvalue.lua

@@ -40,6 +40,9 @@ gvalue.double_arr_typeof = ffi.typeof("const double[?]")
 gvalue.psize_typeof = ffi.typeof("size_t[?]")
 gvalue.mem_typeof = ffi.typeof("unsigned char[?]")
 gvalue.interpolate_typeof = ffi.typeof("VipsInterpolate*")
+gvalue.connection_typeof = ffi.typeof("VipsConnection*")
+gvalue.source_typeof = ffi.typeof("VipsSource*")
+gvalue.target_typeof = ffi.typeof("VipsTarget*")
 
 -- look up some common gtypes at init for speed
 gvalue.gbool_type = gobject_lib.g_type_from_name("gboolean")
@@ -57,6 +60,9 @@ gvalue.blob_type = gobject_lib.g_type_from_name("VipsBlob")
 gvalue.band_format_type = gobject_lib.g_type_from_name("VipsBandFormat")
 gvalue.blend_mode_type = version.at_least(8, 6) and gobject_lib.g_type_from_name("VipsBlendMode") or 0
 gvalue.interpolate_type = gobject_lib.g_type_from_name("VipsInterpolate")
+gvalue.connection_type = gobject_lib.g_type_from_name("VipsConnection")
+gvalue.source_type = gobject_lib.g_type_from_name("VipsSource")
+gvalue.target_type = gobject_lib.g_type_from_name("VipsTarget")
 
 -- gvalue.*_type can be of type cdata or number depending on the OS and Lua version
 -- gtypes as returned by vips_lib can also be of type cdata or number
@@ -159,6 +165,12 @@ gvalue.set = function(gv, value)
         end
     elseif gtype_comp == gvalue.interpolate_type then
         gobject_lib.g_value_set_object(gv, value)
+    elseif gtype_comp == gvalue.connection_type then
+        gobject_lib.g_value_set_object(gv, value)
+    elseif gtype_comp == gvalue.source_type then
+        gobject_lib.g_value_set_object(gv, value)
+    elseif gtype_comp == gvalue.target_type then
+        gobject_lib.g_value_set_object(gv, value)
     else
         error("unsupported gtype for set " .. gvalue.type_name(gtype))
     end
@@ -256,6 +268,15 @@ gvalue.get = function(gv)
     elseif gtype_comp == gvalue.interpolate_type then
         local vo = gobject_lib.g_value_get_object(gv)
         result = ffi.cast(gvalue.interpolate_typeof, vo)
+    elseif gtype_comp == gvalue.connection_type then
+        local vo = gobject_lib.g_value_get_object(gv)
+        result = ffi.cast(gvalue.connection_typeof, vo)
+    elseif gtype_comp == gvalue.source_type then
+        local vo = gobject_lib.g_value_get_object(gv)
+        result = ffi.cast(gvalue.source_typeof, vo)
+    elseif gtype_comp == gvalue.target_type then
+        local vo = gobject_lib.g_value_get_object(gv)
+        result = ffi.cast(gvalue.target_typeof, vo)
     else
         error("unsupported gtype for get " .. gvalue.type_name(gtype))
     end