Added i_stream_create_file() for creating istream from lazily opened file.

diff --git a/src/lib/istream-file.c b/src/lib/istream-file.c
index 6e78162ce6d45cbe30b7c3ab703d43c25aacc42e..ef79173393fe6bb764da41625541857c30686255 100644 (file)
--- a/src/lib/istream-file.c
+++ b/src/lib/istream-file.c
@@ -9,6 +9,7 @@
 
 #include <time.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <sys/stat.h>
 
 struct file_istream {
@@ -35,6 +36,19 @@ static void i_stream_file_close(struct iostream_private *stream)
        _stream->fd = -1;
 }
 
+static int i_stream_file_open(struct istream_private *stream)
+{
+       const char *path = i_stream_get_name(&stream->istream);
+
+       stream->fd = open(path, O_RDONLY);
+       if (stream->fd == -1) {
+               stream->istream.stream_errno = errno;
+               i_error("file_istream.open(%s) failed: %m", path);
+               return -1;
+       }
+       return 0;
+}
+
 static ssize_t i_stream_file_read(struct istream_private *stream)
 {
        struct file_istream *fstream = (struct file_istream *) stream;
@@ -44,6 +58,11 @@ static ssize_t i_stream_file_read(struct istream_private *stream)
        if (!i_stream_get_buffer_space(stream, 1, &size))
                return -2;
 
+       if (stream->fd == -1) {
+               if (i_stream_file_open(stream) < 0)
+                       return -1;
+       }
+
        do {
                if (fstream->file) {
                        ret = pread(stream->fd, stream->w_buffer + stream->pos,
@@ -129,11 +148,18 @@ static const struct stat *
 i_stream_file_stat(struct istream_private *stream, bool exact ATTR_UNUSED)
 {
        struct file_istream *fstream = (struct file_istream *) stream;
+       const char *name = i_stream_get_name(&stream->istream);
 
-       if (fstream->file) {
-               if (fstat(fstream->istream.fd, &fstream->istream.statbuf) < 0) {
-                       i_error("file_istream.fstat(%s) failed: %m",
-                               i_stream_get_name(&stream->istream));
+       if (!fstream->file) {
+               /* return defaults */
+       } else if (stream->fd != -1) {
+               if (fstat(stream->fd, &stream->statbuf) < 0) {
+                       i_error("file_istream.fstat(%s) failed: %m", name);
+                       return NULL;
+               }
+       } else {
+               if (stat(name, &stream->statbuf) < 0) {
+                       i_error("file_istream.fstat(%s) failed: %m", name);
                        return NULL;
                }
        }
@@ -141,8 +167,8 @@ i_stream_file_stat(struct istream_private *stream, bool exact ATTR_UNUSED)
        return &stream->statbuf;
 }
 
-struct istream *i_stream_create_fd(int fd, size_t max_buffer_size,
-                                  bool autoclose_fd)
+static struct istream *
+i_stream_create_file_common(int fd, size_t max_buffer_size, bool autoclose_fd)
 {
        struct file_istream *fstream;
        struct stat st;
@@ -158,7 +184,7 @@ struct istream *i_stream_create_fd(int fd, size_t max_buffer_size,
        fstream->istream.stat = i_stream_file_stat;
 
        /* if it's a file, set the flags properly */
-       if (fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) {
+       if (fd == -1 || (fstat(fd, &st) == 0 && S_ISREG(st.st_mode))) {
                fstream->file = TRUE;
                fstream->istream.istream.blocking = TRUE;
                fstream->istream.istream.seekable = TRUE;
@@ -167,3 +193,20 @@ struct istream *i_stream_create_fd(int fd, size_t max_buffer_size,
 
        return i_stream_create(&fstream->istream, NULL, fd);
 }
+
+struct istream *i_stream_create_fd(int fd, size_t max_buffer_size,
+                                  bool autoclose_fd)
+{
+       i_assert(fd != -1);
+
+       return i_stream_create_file_common(fd, max_buffer_size, autoclose_fd);
+}
+
+struct istream *i_stream_create_file(const char *path, size_t max_buffer_size)
+{
+       struct istream *input;
+
+       input = i_stream_create_file_common(-1, max_buffer_size, TRUE);
+       i_stream_set_name(input, path);
+       return input;
+}

diff --git a/src/lib/istream.h b/src/lib/istream.h
index 648decf33f52f660839d15fc8366be64a778f738..a15d8ed91f422195c4aa0397603fa6ffd766e607 100644 (file)
--- a/src/lib/istream.h
+++ b/src/lib/istream.h
@@ -24,6 +24,9 @@ typedef void istream_callback_t(void *context);
 
 struct istream *i_stream_create_fd(int fd, size_t max_buffer_size,
                                   bool autoclose_fd);
+/* Open the given path only when something is actually tried to be read from
+   the stream. */
+struct istream *i_stream_create_file(const char *path, size_t max_buffer_size);
 struct istream *i_stream_create_mmap(int fd, size_t block_size,
                                     uoff_t start_offset, uoff_t v_size,
                                     bool autoclose_fd);