big update for the db*.nim modules; uses new db_common.nim
This commit is contained in:
Andreas Rumpf
parent
8d5115886f
commit
cb10f30656
4 changed files with 188 additions and 143 deletions
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@ -1,7 +1,7 @@
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#
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#
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# Nim's Runtime Library
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# (c) Copyright 2012 Andreas Rumpf
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# (c) Copyright 2015 Andreas Rumpf
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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@ -42,45 +42,26 @@
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import strutils, sqlite3
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import db_common
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export db_common
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type
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DbConn* = PSqlite3 ## encapsulates a database connection
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Row* = seq[string] ## a row of a dataset. NULL database values will be
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## transformed always to the empty string.
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InstantRow* = Pstmt ## a handle that can be used to get a row's column
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## text on demand
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EDb* = object of IOError ## exception that is raised if a database error occurs
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{.deprecated: [TRow: Row, TDbConn: DbConn].}
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SqlQuery* = distinct string ## an SQL query string
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FDb* = object of IOEffect ## effect that denotes a database operation
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FReadDb* = object of FDb ## effect that denotes a read operation
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FWriteDb* = object of FDb ## effect that denotes a write operation
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{.deprecated: [TRow: Row, TSqlQuery: SqlQuery, TDbConn: DbConn].}
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proc sql*(query: string): SqlQuery {.noSideEffect, inline.} =
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## constructs a SqlQuery from the string `query`. This is supposed to be
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## used as a raw-string-literal modifier:
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## ``sql"update user set counter = counter + 1"``
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##
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## If assertions are turned off, it does nothing. If assertions are turned
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## on, later versions will check the string for valid syntax.
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result = SqlQuery(query)
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proc dbError(db: DbConn) {.noreturn.} =
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## raises an EDb exception.
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var e: ref EDb
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proc dbError*(db: DbConn) {.noreturn.} =
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## raises a DbError exception.
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var e: ref DbError
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new(e)
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e.msg = $sqlite3.errmsg(db)
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raise e
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proc dbError*(msg: string) {.noreturn.} =
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## raises an EDb exception with message `msg`.
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var e: ref EDb
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new(e)
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e.msg = msg
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raise e
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proc dbQuote(s: string): string =
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proc dbQuote*(s: string): string =
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## DB quotes the string.
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if s.isNil: return "NULL"
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result = "'"
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for c in items(s):
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@ -99,7 +80,8 @@ proc dbFormat(formatstr: SqlQuery, args: varargs[string]): string =
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add(result, c)
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proc tryExec*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): bool {.tags: [FReadDb, FWriteDb].} =
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args: varargs[string, `$`]): bool {.
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tags: [ReadDbEffect, WriteDbEffect].} =
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## tries to execute the query and returns true if successful, false otherwise.
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var q = dbFormat(query, args)
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var stmt: sqlite3.Pstmt
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@ -108,8 +90,8 @@ proc tryExec*(db: DbConn, query: SqlQuery,
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result = finalize(stmt) == SQLITE_OK
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proc exec*(db: DbConn, query: SqlQuery, args: varargs[string, `$`]) {.
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tags: [FReadDb, FWriteDb].} =
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## executes the query and raises EDB if not successful.
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tags: [ReadDbEffect, WriteDbEffect].} =
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## executes the query and raises DbError if not successful.
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if not tryExec(db, query, args): dbError(db)
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proc newRow(L: int): Row =
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@ -129,14 +111,14 @@ proc setRow(stmt: Pstmt, r: var Row, cols: cint) =
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if not isNil(x): add(r[col], x)
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iterator fastRows*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): Row {.tags: [FReadDb].} =
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args: varargs[string, `$`]): Row {.tags: [ReadDbEffect].} =
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## Executes the query and iterates over the result dataset.
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##
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## This is very fast, but potentially dangerous. Use this iterator only
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## if you require **ALL** the rows.
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##
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## Breaking the fastRows() iterator during a loop will cause the next
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## database query to raise an [EDb] exception ``unable to close due to ...``.
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## database query to raise a DbError exception ``unable to close due to ...``.
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var stmt = setupQuery(db, query, args)
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var L = (column_count(stmt))
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var result = newRow(L)
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@ -147,9 +129,9 @@ iterator fastRows*(db: DbConn, query: SqlQuery,
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iterator instantRows*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): InstantRow
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{.tags: [FReadDb].} =
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{.tags: [ReadDbEffect].} =
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## same as fastRows but returns a handle that can be used to get column text
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## on demand using []. Returned handle is valid only within the interator body.
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## on demand using []. Returned handle is valid only within the iterator body.
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var stmt = setupQuery(db, query, args)
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while step(stmt) == SQLITE_ROW:
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yield stmt
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@ -164,7 +146,7 @@ proc len*(row: InstantRow): int32 {.inline.} =
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column_count(row)
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proc getRow*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): Row {.tags: [FReadDb].} =
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args: varargs[string, `$`]): Row {.tags: [ReadDbEffect].} =
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## retrieves a single row. If the query doesn't return any rows, this proc
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## will return a Row with empty strings for each column.
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var stmt = setupQuery(db, query, args)
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@ -175,19 +157,19 @@ proc getRow*(db: DbConn, query: SqlQuery,
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if finalize(stmt) != SQLITE_OK: dbError(db)
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proc getAllRows*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): seq[Row] {.tags: [FReadDb].} =
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args: varargs[string, `$`]): seq[Row] {.tags: [ReadDbEffect].} =
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## executes the query and returns the whole result dataset.
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result = @[]
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for r in fastRows(db, query, args):
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result.add(r)
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iterator rows*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): Row {.tags: [FReadDb].} =
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args: varargs[string, `$`]): Row {.tags: [ReadDbEffect].} =
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## same as `FastRows`, but slower and safe.
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for r in fastRows(db, query, args): yield r
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proc getValue*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): string {.tags: [FReadDb].} =
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args: varargs[string, `$`]): string {.tags: [ReadDbEffect].} =
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## executes the query and returns the first column of the first row of the
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## result dataset. Returns "" if the dataset contains no rows or the database
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## value is NULL.
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@ -205,7 +187,7 @@ proc getValue*(db: DbConn, query: SqlQuery,
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proc tryInsertID*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): int64
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{.tags: [FWriteDb], raises: [].} =
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{.tags: [WriteDbEffect], raises: [].} =
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## executes the query (typically "INSERT") and returns the
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## generated ID for the row or -1 in case of an error.
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var q = dbFormat(query, args)
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@ -218,7 +200,7 @@ proc tryInsertID*(db: DbConn, query: SqlQuery,
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result = -1
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proc insertID*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): int64 {.tags: [FWriteDb].} =
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args: varargs[string, `$`]): int64 {.tags: [WriteDbEffect].} =
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## executes the query (typically "INSERT") and returns the
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## generated ID for the row. For Postgre this adds
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## ``RETURNING id`` to the query, so it only works if your primary key is
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@ -228,18 +210,18 @@ proc insertID*(db: DbConn, query: SqlQuery,
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proc execAffectedRows*(db: DbConn, query: SqlQuery,
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args: varargs[string, `$`]): int64 {.
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tags: [FReadDb, FWriteDb].} =
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tags: [ReadDbEffect, WriteDbEffect].} =
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## executes the query (typically "UPDATE") and returns the
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## number of affected rows.
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exec(db, query, args)
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result = changes(db)
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proc close*(db: DbConn) {.tags: [FDb].} =
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proc close*(db: DbConn) {.tags: [DbEffect].} =
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## closes the database connection.
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if sqlite3.close(db) != SQLITE_OK: dbError(db)
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proc open*(connection, user, password, database: string): DbConn {.
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tags: [FDb].} =
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tags: [DbEffect].} =
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## opens a database connection. Raises `EDb` if the connection could not
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## be established. Only the ``connection`` parameter is used for ``sqlite``.
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var db: DbConn
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@ -249,7 +231,7 @@ proc open*(connection, user, password, database: string): DbConn {.
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dbError(db)
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proc setEncoding*(connection: DbConn, encoding: string): bool {.
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tags: [FDb].} =
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tags: [DbEffect].} =
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## sets the encoding of a database connection, returns true for
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## success, false for failure.
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##
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