* UCW Library -- Configuration files
*
* (c) 2001--2006 Robert Spalek <robert@ucw.cz>
- * (c) 2003--2006 Martin Mares <mj@ucw.cz>
+ * (c) 2003--2012 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#ifndef _UCW_CONF_H
#define _UCW_CONF_H
+#include <ucw/clists.h>
+
+struct mempool;
+
+/***
+ * [[conf_ctxt]]
+ * Configuration contexts
+ * ~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The state of the configuration parser is stored within a configuration context.
+ * One such context is automatically created during initialization of the library
+ * and you need not care about more, as long as you use a single configuration file.
+ *
+ * In full generality, you can define as many contexts as you wish and switch
+ * between them. Each thread has its own pointer to the current context, which
+ * must not be shared with other threads.
+ ***/
+
+/** Create a new configuration context. **/
+struct cf_context *cf_new_context(void);
+
+/**
+ * Free a configuration context. The context must not be set as current
+ * for any thread, nor can it be the default context.
+ *
+ * All configuration settings made within the context are rolled back
+ * (except when journalling is turned off). All memory allocated on behalf
+ * of the context is freed, which includes memory obtained by calls to
+ * cf_malloc().
+ **/
+void cf_delete_context(struct cf_context *cc);
+
+/**
+ * Make the given configuration context current and return the previously
+ * active context. Both the new and the old context may be NULL.
+ **/
+struct cf_context *cf_switch_context(struct cf_context *cc);
+
+/***
+ * [[conf_load]]
+ * Safe configuration loading
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * These functions can be used to to safely load or reload configuration.
+ */
+
+/**
+ * Load configuration from @file.
+ * Returns a non-zero value upon error. In that case, all changes to the
+ * configuration specified in the file are undone.
+ **/
+int cf_load(const char *file);
+
+/**
+ * Reload configuration from @file, replace the old one.
+ * If @file is NULL, reload all loaded configuration files and re-apply
+ * bits of configuration passed to cf_set().
+ * Returns a non-zero value upon error. In that case, all configuration
+ * settings are rolled back to the state before calling this function.
+ **/
+int cf_reload(const char *file);
+
+/**
+ * Parse some part of configuration passed in @string.
+ * The syntax is the same as in the <<config:,configuration file>>.
+ * Returns a non-zero value upon error. In that case, all changes to the
+ * configuration specified by the already executed parts of the string
+ * are undone.
+ **/
+int cf_set(const char *string);
+
+/**
+ * Sometimes, the configuration is split to multiple files and when only
+ * some of the are loaded, the settings are not consistent -- for example,
+ * they might have been rejected by a commit hook, because a mandatory setting
+ * is missing.
+ *
+ * This function opens a configuration group, in which multiple files can be
+ * loaded and all commit hooks are deferred until the group is closed.
+ **/
+void cf_open_group(void);
+
+/**
+ * Close a group opened by cf_open_group(). Returns a non-zero value upon error,
+ * which usually means that a commit hook has failed.
+ **/
+int cf_close_group(void);
+
+/**
+ * Return all configuration items to their initial state before loading the
+ * configuration file. If journalling is disabled, it does nothing.
+ **/
+void cf_revert(void);
+
/*** === Data types [[conf_types]] ***/
enum cf_class { /** Class of the configuration item. **/
* save some typing.
*/
-/* Declaration of cf_section */
+/***
+ * Declaration of <<struct_cf_section,`cf_section`>>
+ * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ *
+ * These macros can be used to configure the <<struct_cf_section,`cf_section`>>
+ * structure.
+ ***/
+
+/**
+ * Data type of a section.
+ * If you store the section into a structure, use this macro.
+ *
+ * Storing a section into a structure is useful mostly when you may have multiple instances of the
+ * section (eg. <<conf_multi,array or list>>).
+ *
+ * Example:
+ *
+ * struct list_node {
+ * cnode n; // This one is for the list itself
+ * char *name;
+ * uns value;
+ * };
+ *
+ * static struct clist nodes;
+ *
+ * static struct cf_section node = {
+ * CF_TYPE(struct list_node),
+ * CF_ITEMS {
+ * CF_STRING("name", PTR_TO(struct list_node, name)),
+ * CF_UNS("value", PTR_TO(struct list_node, value)),
+ * CF_END
+ * }
+ * };
+ *
+ * static struct cf_section section = {
+ * CF_LIST("node", &nodes, &node),
+ * CF_END
+ * };
+ *
+ * You could use <<def_CF_STATIC,`CF_STATIC`>> or <<def_CF_DYNAMIC,`CF_DYNAMIC`>>
+ * macros to create arrays.
+ */
#define CF_TYPE(s) .size = sizeof(s)
+/**
+ * An init <<hooks,hook>>.
+ * You can use this to initialize dynamically allocated items (for a dynamic array or list).
+ * The hook returns an error message or NULL if everything was OK.
+ */
#define CF_INIT(f) .init = (cf_hook*) f
+/**
+ * A commit <<hooks,hook>>.
+ * You can use this one to check sanity of loaded data and postprocess them.
+ * You must call @cf_journal_block() if you change anything.
+ *
+ * Return error message or NULL if everything went OK.
+ **/
#define CF_COMMIT(f) .commit = (cf_hook*) f
-#define CF_COPY(f) .copy = (cf_copier*) f
-#define CF_ITEMS .cfg = ( struct cf_item[] )
-#define CF_END { .cls = CC_END }
-/* Configuration items */
+/**
+ * A <<hooks,copy function>>.
+ * You need to provide one for too complicated sections where a memcpy is not
+ * enough to copy it properly. It happens, for example, when you have a dynamically
+ * allocated section containing a list of other sections.
+ *
+ * You return an error message or NULL if you succeed.
+ **/
+#define CF_COPY(f) .copy = (cf_copier*) f /** **/
+#define CF_ITEMS .cfg = ( struct cf_item[] ) /** List of sub-items. **/
+#define CF_END { .cls = CC_END } /** End of the structure. **/
+/***
+ * Declaration of a configuration item
+ * ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ *
+ * Each of these describe single <<struct_cf_item,configuration item>>. They are mostly
+ * for internal use, do not use them directly unless you really know what you are doing.
+ ***/
+
+/**
+ * Static array of items.
+ * Expects you to allocate the memory and provide pointer to it.
+ **/
#define CF_STATIC(n,p,T,t,c) { .cls = CC_STATIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t*) }
+/**
+ * Dynamic array of items.
+ * Expects you to provide pointer to your pointer to data and it will allocate new memory for it
+ * and set your pointer to it.
+ **/
#define CF_DYNAMIC(n,p,T,t,c) { .cls = CC_DYNAMIC, .type = CT_##T, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,t**) }
-#define CF_PARSER(n,p,f,c) { .cls = CC_PARSER, .name = n, .number = c, .ptr = p, .u.par = (cf_parser*) f }
-#define CF_SECTION(n,p,s) { .cls = CC_SECTION, .name = n, .number = 1, .ptr = p, .u.sec = s }
-#define CF_LIST(n,p,s) { .cls = CC_LIST, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,clist*), .u.sec = s }
-#define CF_BITMAP_INT(n,p) { .cls = CC_BITMAP, .type = CT_INT, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*) }
-#define CF_BITMAP_LOOKUP(n,p,t) { .cls = CC_BITMAP, .type = CT_LOOKUP, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*), .u.lookup = t }
-/* Configuration items for basic types */
-#define CF_INT(n,p) CF_STATIC(n,p,INT,int,1)
-#define CF_INT_ARY(n,p,c) CF_STATIC(n,p,INT,int,c)
-#define CF_INT_DYN(n,p,c) CF_DYNAMIC(n,p,INT,int,c)
-#define CF_UNS(n,p) CF_STATIC(n,p,INT,uns,1)
-#define CF_UNS_ARY(n,p,c) CF_STATIC(n,p,INT,uns,c)
-#define CF_UNS_DYN(n,p,c) CF_DYNAMIC(n,p,INT,uns,c)
-#define CF_U64(n,p) CF_STATIC(n,p,U64,u64,1)
-#define CF_U64_ARY(n,p,c) CF_STATIC(n,p,U64,u64,c)
-#define CF_U64_DYN(n,p,c) CF_DYNAMIC(n,p,U64,u64,c)
-#define CF_DOUBLE(n,p) CF_STATIC(n,p,DOUBLE,double,1)
-#define CF_DOUBLE_ARY(n,p,c) CF_STATIC(n,p,DOUBLE,double,c)
-#define CF_DOUBLE_DYN(n,p,c) CF_DYNAMIC(n,p,DOUBLE,double,c)
-#define CF_IP(n,p) CF_STATIC(n,p,IP,u32,1)
-#define CF_IP_ARY(n,p,c) CF_STATIC(n,p,IP,u32,c)
-#define CF_IP_DYN(n,p,c) CF_DYNAMIC(n,p,IP,u32,c)
+#define CF_PARSER(n,p,f,c) { .cls = CC_PARSER, .name = n, .number = c, .ptr = p, .u.par = (cf_parser*) f } /** A low-level parser. **/
+#define CF_SECTION(n,p,s) { .cls = CC_SECTION, .name = n, .number = 1, .ptr = p, .u.sec = s } /** A sub-section. **/
+#define CF_LIST(n,p,s) { .cls = CC_LIST, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,clist*), .u.sec = s } /** A list with sub-items. **/
+#define CF_BITMAP_INT(n,p) { .cls = CC_BITMAP, .type = CT_INT, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*) } /** A bitmap. **/
+#define CF_BITMAP_LOOKUP(n,p,t) { .cls = CC_BITMAP, .type = CT_LOOKUP, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,u32*), .u.lookup = t } /** A bitmap with named bits. **/
+/***
+ * Basic configuration items
+ * ^^^^^^^^^^^^^^^^^^^^^^^^^
+ *
+ * They describe basic data types used in the configuration. This should be enough for
+ * most real-life purposes.
+ *
+ * The parameters are as follows:
+ *
+ * * @n -- name of the item.
+ * * @p -- pointer to the variable where it shall be stored.
+ * * @c -- count.
+ **/
+#define CF_INT(n,p) CF_STATIC(n,p,INT,int,1) /** Single `int` value. **/
+#define CF_INT_ARY(n,p,c) CF_STATIC(n,p,INT,int,c) /** Static array of integers. **/
+#define CF_INT_DYN(n,p,c) CF_DYNAMIC(n,p,INT,int,c) /** Dynamic array of integers. **/
+#define CF_UNS(n,p) CF_STATIC(n,p,INT,uns,1) /** Single `uns` (`unsigned`) value. **/
+#define CF_UNS_ARY(n,p,c) CF_STATIC(n,p,INT,uns,c) /** Static array of unsigned integers. **/
+#define CF_UNS_DYN(n,p,c) CF_DYNAMIC(n,p,INT,uns,c) /** Dynamic array of unsigned integers. **/
+#define CF_U64(n,p) CF_STATIC(n,p,U64,u64,1) /** Single unsigned 64bit integer (`u64`). **/
+#define CF_U64_ARY(n,p,c) CF_STATIC(n,p,U64,u64,c) /** Static array of u64s. **/
+#define CF_U64_DYN(n,p,c) CF_DYNAMIC(n,p,U64,u64,c) /** Dynamic array of u64s. **/
+#define CF_DOUBLE(n,p) CF_STATIC(n,p,DOUBLE,double,1) /** Single instance of `double`. **/
+#define CF_DOUBLE_ARY(n,p,c) CF_STATIC(n,p,DOUBLE,double,c) /** Static array of doubles. **/
+#define CF_DOUBLE_DYN(n,p,c) CF_DYNAMIC(n,p,DOUBLE,double,c) /** Dynamic array of doubles. **/
+#define CF_IP(n,p) CF_STATIC(n,p,IP,u32,1) /** Single IPv4 address. **/
+#define CF_IP_ARY(n,p,c) CF_STATIC(n,p,IP,u32,c) /** Static array of IP addresses. **/.
+#define CF_IP_DYN(n,p,c) CF_DYNAMIC(n,p,IP,u32,c) /** Dynamic array of IP addresses. **/
+/**
+ * A string.
+ * You provide a pointer to a `char *` variable and it will fill it with
+ * dynamically allocated string. For example:
+ *
+ * static char *string = "Default string";
+ *
+ * static struct cf_section section = {
+ * CF_ITEMS {
+ * CF_STRING("string", &string),
+ * CF_END
+ * }
+ * };
+ **/
#define CF_STRING(n,p) CF_STATIC(n,p,STRING,char*,1)
-#define CF_STRING_ARY(n,p,c) CF_STATIC(n,p,STRING,char*,c)
-#define CF_STRING_DYN(n,p,c) CF_DYNAMIC(n,p,STRING,char*,c)
+#define CF_STRING_ARY(n,p,c) CF_STATIC(n,p,STRING,char*,c) /** Static array of strings. **/
+#define CF_STRING_DYN(n,p,c) CF_DYNAMIC(n,p,STRING,char*,c) /** Dynamic array of strings. **/
+/**
+ * One string out of a predefined set.
+ * You provide the set as an array of strings terminated by NULL (similar to @argv argument
+ * of main()) as the @t parameter.
+ *
+ * The configured variable (pointer to `int`) is set to index of the string.
+ * So, it works this way:
+ *
+ * static *strings[] = { "First", "Second", "Third", NULL };
+ *
+ * static int variable;
+ *
+ * static struct cf_section section = {
+ * CF_ITEMS {
+ * CF_LOOKUP("choice", &variable, strings),
+ * CF_END
+ * }
+ * };
+ *
+ * Now, if the configuration contains `choice "Second"`, `variable` will be set to 1.
+ **/
#define CF_LOOKUP(n,p,t) { .cls = CC_STATIC, .type = CT_LOOKUP, .name = n, .number = 1, .ptr = CHECK_PTR_TYPE(p,int*), .u.lookup = t }
+/**
+ * Static array of strings out of predefined set.
+ **/
#define CF_LOOKUP_ARY(n,p,t,c) { .cls = CC_STATIC, .type = CT_LOOKUP, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,int*), .u.lookup = t }
+/**
+ * Dynamic array of strings out of predefined set.
+ **/
#define CF_LOOKUP_DYN(n,p,t,c) { .cls = CC_DYNAMIC, .type = CT_LOOKUP, .name = n, .number = c, .ptr = CHECK_PTR_TYPE(p,int**), .u.lookup = t }
+/**
+ * A user-defined type.
+ * See <<custom_parser,creating custom parsers>> section if you want to know more.
+ **/
#define CF_USER(n,p,t) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = 1, .ptr = p, .u.utype = t }
+/**
+ * Static array of user-defined types (all of the same type).
+ * See <<custom_parser,creating custom parsers>> section.
+ **/
#define CF_USER_ARY(n,p,t,c) { .cls = CC_STATIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
+/**
+ * Dynamic array of user-defined types.
+ * See <<custom_parser,creating custom parsers>> section.
+ **/
#define CF_USER_DYN(n,p,t,c) { .cls = CC_DYNAMIC, .type = CT_USER, .name = n, .number = c, .ptr = p, .u.utype = t }
-/* If you aren't picky about the number of parameters */
+/**
+ * Any number of dynamic array elements
+ **/
#define CF_ANY_NUM -0x7fffffff
-#define DARY_LEN(a) ((uns*)a)[-1]
- // length of a dynamic array
+#define DARY_LEN(a) ((uns*)a)[-1] /** Length of an dynamic array. **/
#define DARY_ALLOC(type,len,val...) ((struct { uns l; type a[len]; }) { .l = len, .a = { val } }).a
// creates a static instance of a dynamic array
* Memory allocation
* ~~~~~~~~~~~~~~~~~
*
- * Uses <<mempool:,memory pools>> for efficiency and journal recovery.
- * You should use these routines when implementing custom parsers.
+ * Each configuration context has one or more <<mempool:,memory pools>>, where all
+ * data related to the configuration are stored.
+ *
+ * The following set of functions allocate from these pools. The allocated memory
+ * is valid as long as the current configuration (when the configuration file is
+ * reloaded or rolled back, or the context is deleted, it gets lost).
+ *
+ * Memory allocated from within custom parsers should be allocated from the pools.
+ *
+ * Please note that the pool is not guaranteed to exist before you call cf_load(),
+ * cf_set(), or cf_getopt() on the particular context.
***/
-struct mempool;
-extern struct mempool *cf_pool; /** A <<mempool:type_mempool,memory pool>> for configuration parser needs. **/
-void *cf_malloc(uns size); /** Returns @size bytes of memory. **/
+struct mempool *cf_get_pool(void); /** Return a pointer to the current configuration pool. **/
+void *cf_malloc(uns size); /** Returns @size bytes of memory allocated from the current configuration pool. **/
void *cf_malloc_zero(uns size); /** Like @cf_malloc(), but zeroes the memory. **/
char *cf_strdup(const char *s); /** Copy a string into @cf_malloc()ed memory. **/
char *cf_printf(const char *fmt, ...) FORMAT_CHECK(printf,1,2); /** printf() into @cf_malloc()ed memory. **/
* Undo journal
* ~~~~~~~~~~~~
*
- * For error recovery
+ * The configuration system uses a simple journaling mechanism, which makes
+ * it possible to undo changes to configuration. A typical example is loading
+ * of configuration by cf_load(): internally, it creates a transaction, applies
+ * all changes specified by the configuration and if one of them fails, the whole
+ * journal is replayed to restore the whole original state. Similarly, cf_reload()
+ * uses the journal to switch between configurations.
+ *
+ * In most cases, you need not care about the journal, except when you need
+ * to change some data from a <<hooks,hook>>, or if you want to call cf_modify_item() and then
+ * undo the changes.
***/
-extern uns cf_need_journal;
+/**
+ * This function can be used to disable the whole journalling mechanism.
+ * It saves some memory, but it makes undoing of configuration changes impossible,
+ * which breaks for example cf_reload().
+ **/
+void cf_set_journalling(int enable);
+/**
+ * When a block of memory is about to be changed, put the old value
+ * into journal with this function. You need to call it from a <<hooks,commit hook>>
+ * if you change anything. It is used internally by low-level parsers.
+ * <<custom_parser,Custom parsers>> do not need to call it, it is called
+ * before them.
+ **/
void cf_journal_block(void *ptr, uns len);
-#define CF_JOURNAL_VAR(var) cf_journal_block(&(var), sizeof(var))
+#define CF_JOURNAL_VAR(var) cf_journal_block(&(var), sizeof(var)) // Store a single value into the journal
+
+struct cf_journal_item; /** Opaque identifier of the journal state. **/
+/**
+ * Starts a new transaction. It returns the current state so you can
+ * get back to it. The @new_pool parameter tells if a new memory pool
+ * should be created and used from now.
+ **/
+struct cf_journal_item *cf_journal_new_transaction(uns new_pool);
+/**
+ * Marks current state as a complete transaction. The @new_pool
+ * parameter tells if the transaction was created with new memory pool
+ * (the parameter must be the same as the one with
+ * @cf_journal_new_transaction() was called with). The @oldj parameter
+ * is the journal state returned from last
+ * @cf_journal_new_transaction() call.
+ **/
+void cf_journal_commit_transaction(uns new_pool, struct cf_journal_item *oldj);
+/**
+ * Returns to an old journal state, reverting anything the current
+ * transaction did. The @new_pool parameter must be the same as the
+ * one you used when you created the transaction. The @oldj parameter
+ * is the journal state you got from @cf_journal_new_transaction() --
+ * it is the state to return to.
+ **/
+void cf_journal_rollback_transaction(uns new_pool, struct cf_journal_item *oldj);
-/* Declaration: conf-section.c */
+/***
+ * [[declare]]
+ * Section declaration
+ * ~~~~~~~~~~~~~~~~~~~
+ **/
+
+/**
+ * Plug another top-level section into the configuration system.
+ * @name is the name in the configuration file,
+ * @sec is pointer to the section description.
+ * If @allow_unknown is set to 0 and a variable not described in @sec
+ * is found in the configuration file, it produces an error.
+ * If you set it to 1, all such variables are ignored.
+ *
+ * Please note that a single section definition cannot be used in multiple
+ * configuration contexts simultaneously.
+ **/
void cf_declare_section(const char *name, struct cf_section *sec, uns allow_unknown);
+/**
+ * Like @cf_declare_section(), but instead of item pointers, the section
+ * contains offsets relative to @ptr. In other words, it does the same
+ * as `CF_SECTION`, but for top-level sections.
+ **/
+void cf_declare_rel_section(const char *name, struct cf_section *sec, void *ptr, uns allow_unknown);
+/**
+ * If you have a section in a structure and you want to initialize it
+ * (eg. if you want a copy of default values outside the configuration),
+ * you can use this. It initializes it recursively.
+ *
+ * This is used mostly internally. You probably do not need it.
+ **/
void cf_init_section(const char *name, struct cf_section *sec, void *ptr, uns do_bzero);
-/*** === Parsers for basic types [[bparser]] ***/
+/***
+ * [[bparser]]
+ * Parsers for basic types
+ * ~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * Each of them gets a string to parse and pointer to store the value.
+ * It returns either NULL or error message.
+ *
+ * The parsers support units. See <<config:units,their list>>.
+ ***/
char *cf_parse_int(const char *str, int *ptr); /** Parser for integers. **/
char *cf_parse_u64(const char *str, u64 *ptr); /** Parser for 64 unsigned integers. **/
char *cf_parse_double(const char *str, double *ptr); /** Parser for doubles. **/
char *cf_parse_ip(const char *p, u32 *varp); /** Parser for IP addresses. **/
-#endif
+/***
+ * [[conf_direct]]
+ * Direct access
+ * ~~~~~~~~~~~~~
+ *
+ * Direct access to configuration items.
+ * You probably should not need this, but in your do, you have to handle
+ * <<journal,journalling>> yourself.
+ ***/
+
+/**
+ * List of operations used on items.
+ * This macro is used to generate internal source code,
+ * but you may be interested in the list of operations it creates.
+ *
+ * Each operation corresponds to the same-named operation
+ * described in <<config:operations,configuration syntax>>.
+ **/
+#define CF_OPERATIONS T(CLOSE) T(SET) T(CLEAR) T(ALL) \
+ T(APPEND) T(PREPEND) T(REMOVE) T(EDIT) T(AFTER) T(BEFORE) T(COPY) T(RESET)
+ /* Closing brace finishes previous block.
+ * Basic attributes (static, dynamic, parsed) can be used with SET.
+ * Dynamic arrays can be used with SET, APPEND, PREPEND.
+ * Sections can be used with SET.
+ * Lists can be used with everything. */
+#define T(x) OP_##x,
+enum cf_operation { CF_OPERATIONS }; /** Allowed operations on items. See <<def_CF_OPERATIONS,`CF_OPERATIONS`>> for list (they have an `OP_` prefix -- it means you use `OP_SET` instead of just `SET`). **/
+#undef T
+
+/**
+ * Searches for a configuration item called @name.
+ * If it is found, it is copied into @item and NULL is returned.
+ * Otherwise, an error is returned and @item is zeroed.
+ **/
+char *cf_find_item(const char *name, struct cf_item *item);
+/**
+ * Performs a single operation on a given item.
+ **/
+char *cf_modify_item(struct cf_item *item, enum cf_operation op, int number, char **pars);
+/***
+ * [[conf_dump]]
+ * Debug dumping
+ * ~~~~~~~~~~~~~
+ ***/
+
+struct fastbuf;
+/**
+ * Write the current state of all configuration items into @fb.
+ **/
+void cf_dump_sections(struct fastbuf *fb);
+
+#endif
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