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Midgard2 Reference Manual | |
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| Top | Description | Object Hierarchy | Properties | ||||
#include <midgard/midgard.h>
MidgardBlob;
struct MidgardBlobClass;
MidgardBlob * midgard_blob_new (MidgardObject *attachment,
const gchar *encoding);
MidgardBlob * midgard_blob_create_blob (MidgardObject *attachment,
const gchar *encoding);
gchar * midgard_blob_read_content (MidgardBlob *self,
gsize *bytes_read);
gboolean midgard_blob_write_content (MidgardBlob *self,
const gchar *content);
GIOChannel * midgard_blob_get_handler (MidgardBlob *self,
const gchar *mode,
GError **error);
const gchar * midgard_blob_get_path (MidgardBlob *self);
gboolean midgard_blob_exists (MidgardBlob *self);
gboolean midgard_blob_remove_file (MidgardBlob *self,
GError **error);
"attachment" MidgardObject* : Read / Write / Construct Only "content" gchar* : Read / Write "encoding" gchar* : Read / Write / Construct Only "parentguid" gchar* : Read / Write
MidgardBlob class provides transparent access to real files located in filesystem. It's a proxy between database objects (usually midgard_attachment) and real files like images or documents.
Main MidgardBlob approaches:
Binary data doesn't have to be stored together with database record ( MidgardObject ).
One object may have unlimited attachments.
One blob may be shared among different objects ( of different classes even ).
You may attach attachment to another attachment ( notes to documentation or image thumbnails ).
Binary file is independent from objects
struct MidgardBlobClass {
GObjectClass parent;
gchar *(*read_content) (MidgardBlob *self, gsize *bytes_read);
gboolean (*write_content) (MidgardBlob *self, const gchar *content);
gboolean (*remove_file) (MidgardBlob *self, GError **error);
gboolean (*exists) (MidgardBlob *self);
const gchar *(*get_path) (MidgardBlob *self);
GIOChannel *(*get_handler) (MidgardBlob *self, const gchar *mode, GError **error);
};
MidgardBlob * midgard_blob_new (MidgardObject *attachment,const gchar *encoding);
Default encoding is UTF-8. Set NULL encoding if such is required.
Instatiate new Midgard Blob object for the given midgard_attachment object.
This constructor defines new relative path for attachment, if midgard_attachment is associated with midgard_blob and its location is empty. In any other case, location is not changed.
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MidgardObject of MIDGARD_TYPE_ATTACHMENT type. |
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file encoding. [allow-none] |
Returns : |
newly instatiated MidgardBlob object or NULL on failure |
MidgardBlob * midgard_blob_create_blob (MidgardObject *attachment,const gchar *encoding);
Invokes midgard_blob_new() and it's designed for language bindings, in whic,
that function can not be invoked explicitly.
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MidgardObject of MIDGARD_TYPE_ATTACHMENT type. |
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file encoding. [allow-none] |
Returns : |
new MidgardBlob instance. [transfer full] |
Since 10.05.1
gchar * midgard_blob_read_content (MidgardBlob *self,gsize *bytes_read);
Returned content should be freed when no longer needed.
bytes_read holds size of returned content.
This function should be used to get content of small files. For large and huge ones midgard_blob_get_handler should be used to get file handle.
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MidgardBlob self instance |
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number of bytes read. [out] |
Returns : |
content of the file, or NULL on failure |
gboolean midgard_blob_write_content (MidgardBlob *self,const gchar *content);
Write given content to a file.
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MidgardBlob self instance. |
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content which should be written to file. |
Returns : |
TRUE if content has been written to file, FALSE otherwise. |
GIOChannel * midgard_blob_get_handler (MidgardBlob *self,const gchar *mode,GError **error);
The main idea is to get file handler. On C level it returns GIOChannel, but language bindings could return typical file handler or anything else which is needed for particular language.
Returned channel is owned by midgard_blob and should not be freed or unreferenced.
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MidgardBlob instance |
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fopen mode (r, w, a, b). Default is 'w'. |
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a pointer to store error. [allow-none] |
Returns : |
GIOChannel or NULL. [transfer none]
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const gchar * midgard_blob_get_path (MidgardBlob *self);
Returned path is owned by midgard_blob and should not be freed. It basically contains blobdir and relative file's location.
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MidgardBlob instance |
Returns : |
absolute path or NULL if path is not set yet. |
gboolean midgard_blob_exists (MidgardBlob *self);
Check if file associated with midgard_blob exists. This function will also return FALSE, if file is not yet associated.
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MidgardBlob instance |
Returns : |
TRUE if file exists, FALSE otherwise |
gboolean midgard_blob_remove_file (MidgardBlob *self,GError **error);
Deletes a file which is associated with blob and located at attachment's location which is initialized for blob. midgard_blob_exists should be invoked if file may be already deleted, for example when one file is shared among many attachments.
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MidgardBlob self instance. |
Returns : |
TRUE on success, FALSE otherwise |