vcs-svn: move remaining repo_tree functions to fast_export.h

These used to be for manipulating the in-memory repo_tree structure,
but nowadays they are convenience wrappers to handle a few git-vs-svn
mismatches:

 1. Git does not track empty directories but Subversion does.  When
    looking up a path in git that Subversion thinks exists and finding
    nothing, we can safely assume that the path represents a
    directory.  This is needed when a later Subversion revision
    modifies that directory.

 2. Subversion allows deleting a file by copying.  In Git fast-import
    we have to handle that more explicitly as a deletion.

These are details of the tool's interaction with git fast-import.
Move them to fast_export.c, where other such details are handled.

This way the function names do not start with a repo_ prefix that
would clash with the repository object introduced in
v2.14.0-rc0~38^2~16 (repository: introduce the repository object,
2017-06-22) or an svn_ prefix that would clash with libsvn (in case
someone wants to link this code with libsvn some day).

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: jrn

Makefile

@@ -1942,7 +1942,6 @@ XDIFF_OBJS += xdiff/xhistogram.o
 
 VCSSVN_OBJS += vcs-svn/line_buffer.o
 VCSSVN_OBJS += vcs-svn/sliding_window.o
-VCSSVN_OBJS += vcs-svn/repo_tree.o
 VCSSVN_OBJS += vcs-svn/fast_export.o
 VCSSVN_OBJS += vcs-svn/svndiff.o
 VCSSVN_OBJS += vcs-svn/svndump.o

vcs-svn/fast_export.c

@@ -6,7 +6,6 @@
 #include "cache.h"
 #include "quote.h"
 #include "fast_export.h"
-#include "repo_tree.h"
 #include "strbuf.h"
 #include "svndiff.h"
 #include "sliding_window.h"
@@ -312,6 +311,40 @@ int fast_export_ls(const char *path, uint32_t *mode, struct strbuf *dataref)
 	return parse_ls_response(get_response_line(), mode, dataref);
 }
 
+const char *fast_export_read_path(const char *path, uint32_t *mode_out)
+{
+	int err;
+	static struct strbuf buf = STRBUF_INIT;
+
+	strbuf_reset(&buf);
+	err = fast_export_ls(path, mode_out, &buf);
+	if (err) {
+		if (errno != ENOENT)
+			die_errno("BUG: unexpected fast_export_ls error");
+		/* Treat missing paths as directories. */
+		*mode_out = S_IFDIR;
+		return NULL;
+	}
+	return buf.buf;
+}
+
+void fast_export_copy(uint32_t revision, const char *src, const char *dst)
+{
+	int err;
+	uint32_t mode;
+	static struct strbuf data = STRBUF_INIT;
+
+	strbuf_reset(&data);
+	err = fast_export_ls_rev(revision, src, &mode, &data);
+	if (err) {
+		if (errno != ENOENT)
+			die_errno("BUG: unexpected fast_export_ls_rev error");
+		fast_export_delete(dst);
+		return;
+	}
+	fast_export_modify(dst, mode, data.buf);
+}
+
 void fast_export_blob_delta(uint32_t mode,
 				uint32_t old_mode, const char *old_data,
 				off_t len, struct line_buffer *input)

vcs-svn/fast_export.h

@@ -28,4 +28,7 @@ int fast_export_ls_rev(uint32_t rev, const char *path,
 int fast_export_ls(const char *path,
 			uint32_t *mode_out, struct strbuf *dataref_out);
 
+void fast_export_copy(uint32_t revision, const char *src, const char *dst);
+const char *fast_export_read_path(const char *path, uint32_t *mode_out);
+
 #endif

vcs-svn/repo_tree.c

@@ -8,7 +8,6 @@
  */
 
 #include "cache.h"
-#include "repo_tree.h"
 #include "fast_export.h"
 #include "line_buffer.h"
 #include "strbuf.h"
@@ -233,7 +232,7 @@ static void handle_node(void)
 		node_ctx.action = NODEACT_ADD;
 	}
 	if (node_ctx.srcRev) {
-		svn_repo_copy(node_ctx.srcRev, node_ctx.src.buf, node_ctx.dst.buf);
+		fast_export_copy(node_ctx.srcRev, node_ctx.src.buf, node_ctx.dst.buf);
 		if (node_ctx.action == NODEACT_ADD)
 			node_ctx.action = NODEACT_CHANGE;
 	}
@@ -249,7 +248,7 @@ static void handle_node(void)
 		old_data = NULL;
 	} else if (node_ctx.action == NODEACT_CHANGE) {
 		uint32_t mode;
-		old_data = svn_repo_read_path(node_ctx.dst.buf, &mode);
+		old_data = fast_export_read_path(node_ctx.dst.buf, &mode);
 		if (mode == S_IFDIR && type != S_IFDIR)
 			die("invalid dump: cannot modify a directory into a file");
 		if (mode != S_IFDIR && type == S_IFDIR)