Subject: [PATCH v19 5/5] Add support for implementing custom COPY TO/FROM format as extension

From: Sutou Kouhei <[email-masked]>
Date: Tue, 23 Jan 2024 15:12:43 +0900

For custom COPY TO format implementation:

* Add CopyToStateData::opaque that can be used to keep data for custom
  COPY TO format implementation
* Export CopySendEndOfRow() to flush data in CopyToStateData::fe_msgbuf
  as CopyToStateFlush()

For custom COPY FROM format implementation:

* Add CopyFromStateData::opaque that can be used to keep data for
  custom COPY From format implementation
* Export CopyReadBinaryData() to read the next data as
  CopyFromStateRead()
---
 src/backend/commands/copyfromparse.c | 14 ++++++++++++++
 src/backend/commands/copyto.c        | 14 ++++++++++++++
 src/include/commands/copyapi.h       | 10 ++++++++++
 3 files changed, 38 insertions(+)

diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index 74844103228..a115d7f9e26 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -739,6 +739,20 @@ CopyReadBinaryData(CopyFromState cstate, char *dest, int nbytes)
 	return copied_bytes;
 }
 
+/*
+ * CopyFromStateRead
+ *
+ * Export CopyReadBinaryData() for extensions. We want to keep
+ * CopyReadBinaryData() as a static function for
+ * optimization. CopyReadBinaryData() calls in this file may be optimized by
+ * a compiler.
+ */
+int
+CopyFromStateRead(CopyFromState cstate, char *dest, int nbytes)
+{
+	return CopyReadBinaryData(cstate, dest, nbytes);
+}
+
 /*
  * Read raw fields in the next line for COPY FROM in text or csv mode.
  * Return false if no more lines.
diff --git a/src/backend/commands/copyto.c b/src/backend/commands/copyto.c
index 54aa6cdecaf..b8d0e996117 100644
--- a/src/backend/commands/copyto.c
+++ b/src/backend/commands/copyto.c
@@ -500,6 +500,20 @@ CopySendEndOfRow(CopyToState cstate)
 	resetStringInfo(fe_msgbuf);
 }
 
+/*
+ * CopyToStateFlush
+ *
+ * Export CopySendEndOfRow() for extensions. We want to keep
+ * CopySendEndOfRow() as a static function for
+ * optimization. CopySendEndOfRow() calls in this file may be optimized by a
+ * compiler.
+ */
+void
+CopyToStateFlush(CopyToState cstate)
+{
+	CopySendEndOfRow(cstate);
+}
+
 /*
  * These functions do apply some data conversion
  */
diff --git a/src/include/commands/copyapi.h b/src/include/commands/copyapi.h
index e298b19860c..5665408eaa0 100644
--- a/src/include/commands/copyapi.h
+++ b/src/include/commands/copyapi.h
@@ -299,8 +299,13 @@ typedef struct CopyFromStateData
 #define RAW_BUF_BYTES(cstate) ((cstate)->raw_buf_len - (cstate)->raw_buf_index)
 
 	uint64		bytes_processed;	/* number of bytes processed so far */
+
+	/* For custom format implementation */
+	void	   *opaque;			/* private space */
 } CopyFromStateData;
 
+extern int	CopyFromStateRead(CopyFromState cstate, char *dest, int nbytes);
+
 
 typedef struct CopyToStateData *CopyToState;
 
@@ -402,6 +407,11 @@ typedef struct CopyToStateData
 	FmgrInfo   *out_functions;	/* lookup info for output functions */
 	MemoryContext rowcontext;	/* per-row evaluation context */
 	uint64		bytes_processed;	/* number of bytes processed so far */
+
+	/* For custom format implementation */
+	void	   *opaque;			/* private space */
 } CopyToStateData;
 
+extern void CopyToStateFlush(CopyToState cstate);
+
 #endif							/* COPYAPI_H */
-- 
2.45.2

----Next_Part(Tue_Jul_30_16_13_06_2024_473)----