tabs and tab overview

shm.h

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+#pragma once
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <sys/types.h>
+
+#include <pixman.h>
+#include <wayland-client.h>
+
+#include <tllist.h>
+
+#include "config.h"
+#include "wayland.h"
+
+struct damage;
+
+struct buffer {
+    int width;
+    int height;
+    int stride;
+
+    void *data;
+
+    struct wl_buffer *wl_buf;
+    pixman_image_t **pix;
+    size_t pix_instances;
+
+    unsigned age;
+
+    /*
+     * First item in the array is used to track frame-to-frame
+     * damage. This is used when re-applying damage from the last
+     * frame, when the compositor doesn't release buffers immediately
+     * (forcing us to double buffer)
+     *
+     * The remaining items are used to track surface damage. Each
+     * worker thread adds its own cell damage to "its" region. When
+     * the frame is done, all damage is converted to a single region,
+     * which is then used in calls to wl_surface_damage_buffer().
+     */
+    pixman_region32_t *dirty;
+};
+
+void shm_fini(void);
+
+/* TODO: combine into shm_init() */
+void shm_set_max_pool_size(off_t max_pool_size);
+void shm_set_min_stride_alignment(size_t min_stride_alignment);
+
+struct buffer_chain;
+struct buffer_chain *shm_chain_new(
+    struct wayland *wayl, bool scrollable, size_t pix_instances,
+    enum shm_bit_depth desired_bit_depth,
+    void (*release_cb)(struct buffer *buf, void *data), void *cb_data);
+void shm_chain_free(struct buffer_chain *chain);
+
+enum shm_bit_depth shm_chain_bit_depth(const struct buffer_chain *chain);
+ 
+/*
+ * Returns a single buffer.
+ *
+ * May returned a cached buffer. If so, the buffer's age indicates how
+ * many shm_get_buffer() calls have been made for the same
+ * width/height while the buffer was still busy.
+ *
+ * A newly allocated buffer has an age of 1234.
+ */
+struct buffer *shm_get_buffer(struct buffer_chain *chain, int width, int height);
+/*
+ * Returns many buffers, described by 'info', all sharing the same SHM
+ * buffer pool.
+ *
+ * Never returns cached buffers. However, the newly created buffers
+ * are all inserted into the regular buffer cache, and are treated
+ * just like buffers created by shm_get_buffer().
+ *
+ * This function is useful when allocating many small buffers, with
+ * (roughly) the same life time.
+ *
+ * Buffers are tagged for immediate purging, and will be destroyed as
+ * soon as the compositor releases them.
+ */
+void shm_get_many(
+    struct buffer_chain *chain, size_t count,
+    int widths[static count], int heights[static count],
+    struct buffer *bufs[static count]);
+
+void shm_did_not_use_buf(struct buffer *buf);
+
+bool shm_can_scroll(const struct buffer *buf);
+bool shm_scroll(struct buffer *buf, int rows,
+                int top_margin, int top_keep_rows,
+                int bottom_margin, int bottom_keep_rows);
+
+void shm_addref(struct buffer *buf);
+void shm_unref(struct buffer *buf);
+
+void shm_purge(struct buffer_chain *chain);