copyfrom_internal.h

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/*-------------------------------------------------------------------------
 *
 * copyfrom_internal.h
 *    Internal definitions for COPY FROM command.
 *
 *
 * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/commands/copyfrom_internal.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef COPYFROM_INTERNAL_H
#define COPYFROM_INTERNAL_H
 
#include "commands/copy.h"
#include "commands/trigger.h"
 
/*
 * Represents the different source cases we need to worry about at
 * the bottom level
 */
typedef enum CopySource
{
    COPY_FILE,                  /* from file (or a piped program) */
    COPY_FRONTEND,              /* from frontend */
    COPY_CALLBACK               /* from callback function */
} CopySource;
 
/*
 *  Represents the end-of-line terminator type of the input
 */
typedef enum EolType
{
    EOL_UNKNOWN,
    EOL_NL,
    EOL_CR,
    EOL_CRNL
} EolType;
 
/*
 * Represents the insert method to be used during COPY FROM.
 */
typedef enum CopyInsertMethod
{
    CIM_SINGLE,                 /* use table_tuple_insert or ExecForeignInsert */
    CIM_MULTI,                  /* always use table_multi_insert or
                                 * ExecForeignBatchInsert */
    CIM_MULTI_CONDITIONAL       /* use table_multi_insert or
                                 * ExecForeignBatchInsert only if valid */
} CopyInsertMethod;
 
/*
 * This struct contains all the state variables used throughout a COPY FROM
 * operation.
 */
typedef struct CopyFromStateData
{
    /* low-level state data */
    CopySource  copy_src;       /* type of copy source */
    FILE       *copy_file;      /* used if copy_src == COPY_FILE */
    StringInfo  fe_msgbuf;      /* used if copy_src == COPY_FRONTEND */
 
    EolType     eol_type;       /* EOL type of input */
    int         file_encoding;  /* file or remote side's character encoding */
    bool        need_transcoding;   /* file encoding diff from server? */
    Oid         conversion_proc;    /* encoding conversion function */
 
    /* parameters from the COPY command */
    Relation    rel;            /* relation to copy from */
    List       *attnumlist;     /* integer list of attnums to copy */
    char       *filename;       /* filename, or NULL for STDIN */
    bool        is_program;     /* is 'filename' a program to popen? */
    copy_data_source_cb data_source_cb; /* function for reading data */
 
    CopyFormatOptions opts;
    bool       *convert_select_flags;   /* per-column CSV/TEXT CS flags */
    Node       *whereClause;    /* WHERE condition (or NULL) */
 
    /* these are just for error messages, see CopyFromErrorCallback */
    const char *cur_relname;    /* table name for error messages */
    uint64      cur_lineno;     /* line number for error messages */
    const char *cur_attname;    /* current att for error messages */
    const char *cur_attval;     /* current att value for error messages */
    bool        relname_only;   /* don't output line number, att, etc. */
 
    /*
     * Working state
     */
    MemoryContext copycontext;  /* per-copy execution context */
 
    AttrNumber  num_defaults;   /* count of att that are missing and have
                                 * default value */
    FmgrInfo   *in_functions;   /* array of input functions for each attrs */
    Oid        *typioparams;    /* array of element types for in_functions */
    int        *defmap;         /* array of default att numbers related to
                                 * missing att */
    ExprState **defexprs;       /* array of default att expressions for all
                                 * att */
    bool       *defaults;       /* if DEFAULT marker was found for
                                 * corresponding att */
    bool        volatile_defexprs;  /* is any of defexprs volatile? */
    List       *range_table;    /* single element list of RangeTblEntry */
    List       *rteperminfos;   /* single element list of RTEPermissionInfo */
    ExprState  *qualexpr;
 
    TransitionCaptureState *transition_capture;
 
    /*
     * These variables are used to reduce overhead in COPY FROM.
     *
     * attribute_buf holds the separated, de-escaped text for each field of
     * the current line.  The CopyReadAttributes functions return arrays of
     * pointers into this buffer.  We avoid palloc/pfree overhead by re-using
     * the buffer on each cycle.
     *
     * In binary COPY FROM, attribute_buf holds the binary data for the
     * current field, but the usage is otherwise similar.
     */
    StringInfoData attribute_buf;
 
    /* field raw data pointers found by COPY FROM */
 
    int         max_fields;
    char      **raw_fields;
 
    /*
     * Similarly, line_buf holds the whole input line being processed. The
     * input cycle is first to read the whole line into line_buf, and then
     * extract the individual attribute fields into attribute_buf.  line_buf
     * is preserved unmodified so that we can display it in error messages if
     * appropriate.  (In binary mode, line_buf is not used.)
     */
    StringInfoData line_buf;
    bool        line_buf_valid; /* contains the row being processed? */
 
    /*
     * input_buf holds input data, already converted to database encoding.
     *
     * In text mode, CopyReadLine parses this data sufficiently to locate line
     * boundaries, then transfers the data to line_buf. We guarantee that
     * there is a \0 at input_buf[input_buf_len] at all times.  (In binary
     * mode, input_buf is not used.)
     *
     * If encoding conversion is not required, input_buf is not a separate
     * buffer but points directly to raw_buf.  In that case, input_buf_len
     * tracks the number of bytes that have been verified as valid in the
     * database encoding, and raw_buf_len is the total number of bytes stored
     * in the buffer.
     */
#define INPUT_BUF_SIZE 65536    /* we palloc INPUT_BUF_SIZE+1 bytes */
    char       *input_buf;
    int         input_buf_index;    /* next byte to process */
    int         input_buf_len;  /* total # of bytes stored */
    bool        input_reached_eof;  /* true if we reached EOF */
    bool        input_reached_error;    /* true if a conversion error happened */
    /* Shorthand for number of unconsumed bytes available in input_buf */
#define INPUT_BUF_BYTES(cstate) ((cstate)->input_buf_len - (cstate)->input_buf_index)
 
    /*
     * raw_buf holds raw input data read from the data source (file or client
     * connection), not yet converted to the database encoding.  Like with
     * 'input_buf', we guarantee that there is a \0 at raw_buf[raw_buf_len].
     */
#define RAW_BUF_SIZE 65536      /* we palloc RAW_BUF_SIZE+1 bytes */
    char       *raw_buf;
    int         raw_buf_index;  /* next byte to process */
    int         raw_buf_len;    /* total # of bytes stored */
    bool        raw_reached_eof;    /* true if we reached EOF */
 
    /* Shorthand for number of unconsumed bytes available in raw_buf */
#define RAW_BUF_BYTES(cstate) ((cstate)->raw_buf_len - (cstate)->raw_buf_index)
 
    uint64      bytes_processed;    /* number of bytes processed so far */
} CopyFromStateData;
 
extern void ReceiveCopyBegin(CopyFromState cstate);
extern void ReceiveCopyBinaryHeader(CopyFromState cstate);
 
#endif                          /* COPYFROM_INTERNAL_H */